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El Dorado County - List of Quarries, Etc.

(* Please note this list does not include sand or gravel quarries.)

  • El Dorado County Mines (and Quarries), by Doug Noble, El Dorado County Library web site. (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)

  • American River (north side of), El Dorado County, California - the California Slate Quarry (Slate) (From The Structural and Industrial Materials of California, Bulletin No. 38, California, State Mining Bureau, San Francisco, California, 1906.)

    "California Slate Quarry, in Secs. 23 and 25, T. 11 N., R. 10 E., M. D. M.; F. S. Chadbourne, 121 New Montgomery street, San Francisco, owner. It is located on the north side of the American River. The material contains much iron pyrites. The trimmed slabs left in the yard are nearly all iron-stained, and some of them crumbling by the disintegration of the pyrite since their exposure to the air. The pyrite appears to be much worse on the west side of the quarry opening than on the east side. It is probably confined largely to certain layers of the slate, and the quarry opening unfortunately struck one of these bad streaks. The quarry has not been operated in the last few years."

  • Auburn (south of), El Dorado County, California – Alabaster Cave Lime Quarry

    Alabaster Cave Limestone Quarry – See Rattlesnake Bridge south of Auburn below.

  • Auburn (northeast of), El Dorado County, California – California Rock and Gravel Company (Limestone) (Excerpts from "The Cool-Cave Valley Limestone Deposits, El Dorado and Placer Counties, California," by William B. Clark, Junior Mining Geologist, California Division of Mines, California Journal of Mines and Geology, Vol. 50, Nos. 3 and 4, July-October 1954, pp. 439-466. (Used with permission, California Department of Conservation, California Geological Survey.)

    California Rock and Gravel Co. – See Mountain Quarries for history and photographs of the quarries.

  • Auburn (east of), El Dorado County, California - Cave Valley Limestone Quarry (AKA Cool-Cave Valley) (Limestone) (Below are several different entries from sources and publications of various dates relating to this area in El Dorado County of limestone quarrying.)

    • Cave Valley Limestone Quarry circa 1906 (The following information is from The Structural and Industrial Materials of California, Bulletin No. 38, California, State Mining Bureau, San Francisco, California, 1906.)

      "At Cave Valley, east of Auburn, is another limestone quarry and limekilns."

    • Cave Valley Limestone Quarry (Excerpt from Report XV of the State Mineralogist, Mines and Mineral Resources of Portions of California, Chapters of State Mineralogist's Report Biennial Period 1915-1916, Part III. The Counties of El Dorado, Placer, Sacramento, Yuba, California State Mining Bureau, 1919, pp. 271-459. Used with permission, California Department of Conservation, California Geological Survey.)

      "Cave Valley Limestone Quarry. See our Bulletin 38, p. 68. Situated 9 miles east of Newcastle, Placer County. The limestone is crystalline, granular, white, clouded white, and blue in color. Idle. H. Cowell, of San Francisco, owner."

    • Cool-Cave Valley Limestone Quarries and Deposits – Cowell Cave Valley Deposit (circa 1947) (Limestone) (Excerpts from "Limestone in California," by Clarence A. Logan, California Journal of Mines and Geology, Vol. 43, No. 3, July 1947, California Division of Mines, San Francisco, California, pp. 175-357. Used with permission, California Department of Conservation, California Geological Survey.)

      "Cowell Cave Valley Deposit. Owner of this deposit is Henry Cowell Lime and Cement Company, 2 Market Street, San Francisco. It is in secs. 6, 7, and 18, T. 12 N., R. 9 E., M.D., 5 to 6 miles by good road east of Auburn. The total land holdings on this deposit cover 947 acres and the deposit extends for about 2 miles in length with an exposed width of 200 to 400 feet. It includes one large lens and part of another 1 ¼ miles on this property, the northern portion of the latter having been worked on an adjoining property for a part of at least every year from 1910 to 1942. It was mined in a large open pit up to the Cowell property line, and to a depth of 800 feet. This northerly lens was traversed by the Middle Fork of the American River and the canyon permitted operation to this depth by starting near the river level.

      "Aside from their exceptional size, these limestone deposits are typical of the series of roughly lens-shaped bodies found in the Calaveras (Carboniferous, Mississippian) meta-sediments of this section of the Sierra Nevada. The series of beds have been folded and compressed so that the lenses of limestone stand nearly on edge, and where exposed by erosion they have the character of frozen veins. So general and intense has been the metamorphism that the limestone is all crystallized, firm to tenacious in texture, and generally devoid of visible organic remains, except for the finely divided carbonaceous residue which gives it the prevalent blue-gray to nearly black color, which is subdued by weathering to a typical dove-gray shade. But it is remarkable that, in spite of the metamorphism, every one of these deposits was found to be a 'stinkestein' (fetid limestone), giving a more or less pronounced odor on being hammered.

      "Cool Valley Lime Company quarried the limestone on both sides of the Auburn-Cool road and made lime in two kilns 40 to 50 years ago. The workings were shallow, as the limestone outcrops there do not stand much higher than the general ground level. The fullest development without recourse to hoisting would require entry from the south side of the river canyon and if the south lens proved to extend as deep as the north lens, the tonnage of limestone in it alone to a depth of 500 feet would be sufficient to justify a plant of any size.

      "The following analyses were of large samples taken by chipping good sized pieces at regular intervals, across the widths indicated:

      Sample across 270 feet

      Insoluble, 0.22 percent
      Fe2O3 and A12O3, 0.25 percent
      CaCo3, 98.50 percent
      MgCo3, 0.34 percent
      Total, 99.31 percent

      Sample across 400 feet

      Insoluble, 1.02 percent
      Fe2O3 and A12O3, 0.29 percent
      CaCo3, 98.14 percent
      MgCO3, 0.45 percent
      Total, 99.90 percent

      "This property was leased to California Rock and Gravel Company, 1800 Hobart Building, San Francisco, in 1946 and at time of the author's visit in October 1946 was being worked for them under contract by E. B. Bishop. Several hundred tons of limestone was being shipped daily from Auburn.

      "A face 50 feet high by 300 feet long has been opened on the limestone in section 7 about a quarter of a mile north of the highway. Five wagon drills are operated 2 shifts, drilling 30-foot holes on 6-foot centers. These are shot with 60 percent Atlas dynamite, as the limestone is tough and hard. Large blocks of stone are blasted small enough to load with 1 ½- and 2 ½-cubic-yard power shovels into trucks, which deliver limestone to the 30- by 42-inch primary crusher, which is set to 7 ½ inches and operated by 100-horsepower motor. From this it passes by belt conveyor to a trommel with 6-inch square holes, and oversize goes to secondary crusher. Another belt conveyor delivers all stone to a double-deck screen on top of the loading bins. This screen delivers two sizes, 2 inch by 4 inch and 4 inch by 6 inch to separate bins for loading into trucks which haul it to railroad cars at Auburn. The minus 2-inch material is carried by a belt conveyor to a stockpile. Bin capacity is 900 tons. Three portable air compressors are used, two drills requiring a 500-cubic foot compressor. Electric power is supplied by Pacific Gas & Electric Company.

      "At present a 7-day week is worked and stone is being shipped to beet-sugar refineries, which require a large tonnage during their operating season, in autumn and winter. These refineries burn the limestone in vertical kilns, so demand a hard, fine-grained stone that will make good lump lime. This deposit, as shown in analyses of samples taken by the writer, is a very high-grade, high-calcium limestone, and according to Boyd Oliver, vice president of California Rock and Gravel Company, recent analyses have indicated over 99 percent CaCO3, with less than 0.025 percent iron.

      "California Rock and Gravel Company took over operation of the property, doing considerable advance prospecting during the early part of 1947, followed by heavy production throughout the dry season."

      B. California Rock and Gravel Company Plant - Cowell Cave Valley limestone deposit near Cool, El Dorado County, October 1946.

      California Rock and Gravel Company Plant - Cowell Cave Valley limestone deposit near Cool

    • Cool-Cave Valley Limestone Deposits (Limestone) (Excerpts from "The Cool-Cave Valley Limestone Deposits, El Dorado and Placer Counties, California," by William B. Clark, Junior Mining Geologist, California Division of Mines, California Journal of Mines and Geology, Vol. 50, Nos. 3 and 4, July-October 1954, pp. 439-466. (Used with permission, California Department of Conservation, California Geological Survey.)

      Frontispiece. Aerial view of Cool-Cave Valley limestone deposits, camera facing south. Mountain Quarries of the Pacific Portland Cement Company in the foreground, quarry of the California Rock and Gravel Company in middle-ground. Cave Valley and adjacent gulches are roughly aligned parallel to the regional structure which is slightly north of west.

      Aerial view of Cool-Cave Valley limestone deposits

      The following information is taken from "Table 1. Limestone deposits in the general area of the Cool-Cave Valley limestone," (circa 1954) on pages 462 and 463:

      (No. on map, Plate 3) 5; (Deposit) Cool-Cave Valley; (Owner) North ¼ owned by Pacific Portland Cement Company, 417 Montgomery Street, San Francisco. South ¾ owned by Henry Cowell Lime and Cement Company, 2 Market Street, San Francisco; (Location) Secs. 6, 7, 18, T. 12 N., R. 9 E., M.D.; (References) Hanks 84:107; Crawford 94:391-392; Lindgren 94:3; Crawford 96:628; Aubury 02:17; 06:68; Tucker 19:304, 390-391; Logan 21:431-432; 24:8; Young 25:13-16; Logan 26:442, 443; 27:282; Laizure 27:208; 29:251; Logan 38:277, 280; 47:222, 224-226, 232-233; Bowen and Crippen 48:73, 80.

      Abstract

      "The Cool-Cave Valley limestone deposit consists of two elongate lenses extending in northerly direction through the Sierran foothills about 4 miles east of Auburn, California. Limestone has been quarried from both lenses. Mountain Quarries, at the north end of the deposit, was one of the chief sources of limestone in northern California from 1910 to 1930. The California Rock and Gravel Company now (circa 1954) operates a quarry for the production of limestone for use in sugar refineries in the central portion of the deposit adjacent to the idle Mountain Quarries.

      "The geologic structure of the area has a north to northwest trend. In the area immediately surrounding the limestone, the rock is composed dynamothermally metamorphosed fine-grained basic volcanic rocks commonly called greenstone, of undetermined age. To the west and north of the limestone are extensive beds of Carboniferous metamorphosed marine sediments and masses of amphibolite. Both the limestone and the volcanic rocks are cut by dikes of medium-grained quartz diorite and diorite porphyry. The exact relationship of the limestone with the other rocks of the area is not clear.

      "At Mountain Quarries, limestone was quarried by the glory hole method. from the quarry it was trammed through an adit to the crushing plant. Most of the stone was then shipped via railroad to the Pacific Portland Cement Company plant. After 1930 production was largely used in beet sugar refineries. Peak production varied from 1200 to 1500 tons per day.

      "Since 1946, the California Rock and Gravel Company has operated a quarry in the central portion of the deposit. The 'coyote hole' method of quarrying is employed, whereby an entire year's production of 150,000 tons is dislodged in one blast. The rock is then run through a crusher and a sizing plant. Coarser sizes are shipped via railroad to beet sugar refineries while the finer material is trucked to a lime plant near Rattlesnake Bridge or sold as road metal. Estimated reserves of the entire deposit are 18,225,000 tons per 100 feet of depth.

      Introduction

      "Approximately 4 miles east of Auburn, California is the Cool-Cave Valley limestone deposit. the deposit consists of two elongate limestone lenses extending from a point half a mile north of the town of Cool, El Dorado County, north for a distance of approximately 1 ¾ miles to just north of the Middle Fork of the American River in Placer County. The two lenses lie in secs. 6 and 7, T. 12 N., R. 9 E., M.D.M. The bulk of the deposit is in El Dorado County.

      "The Cool-Cave Valley area is traversed by State Highway 49 which crosses the south end of the deposit. Dirt roads branching off Highway 49 give access to nearly all parts of the limestone deposit. The nearest railroad is the main line of the Southern Pacific which runs through Auburn in a northeasterly direction. Until 1942, Mountain Quarries of the Pacific Portland Cement Company at the north end of the deposit on the Middle Fork of the American River, was served by a company-owned railroad which connected with the Southern Pacific at Auburn. The old railroad right-of-way is now a dirt road.

      "Topography of the region is characterized by steep-walled canyons and moderately steep peaks. Elevations vary from 500 to 1800 feet. The topography and drainage pattern is partly controlled by the north to northwest trend of the major geologic structures. As the Sierra Nevada has been tilted in a general southwesterly direction, the main rivers and stream flow in that general direction, while the small tributaries tend to flow to the northwest or southeast in response to the structure.

      Figure 1. Ruins of old lime kiln at the south Cool-Cave Valley deposit on the east side of State Highway 49.

      Ruins of old lime kiln at the south Cool-Cave Valley

      History

      "Limestone has been quarried at both of the lenses. Lime was produced in the early history of the operations by burning the lime with wood in stone lime kilns. During the 1880's, the Cave Valley deposit was operated by the firm of Davis and Cowell (Hanks, 1884). In 1894 the Cave Valley Lime Company produced 150 to 160 tons of lime per month during the summer from two kilns which were located alongside of the Auburn-Cool road (Crawford, 1894). Ruins of these old kilns may be seen today north of Cool close to State Highway 49.

      "In 1910 the Pacific Portland Cement Company opened its Mountain Quarries on the south side of the Middle Fork of the American River for the production of limestone for use in the company-owned cement plant in Solano County (Logan, 1947, p. 232). From 1910 until about 1930 this quarry was one of the chief sources of limestone for the cement, sugar, and steel industries in northern California. After 1930 production was smaller, the cement plant in Solano County having been idle part of the time. In 1942 the quarry was shut down, and the railroad and crushing plant were dismantled. Since that date, it has been idle.

      "In 1946 the central portion of the northern lens, just south of Mountain Quarries, owned by the Henry Cowell Lime and Cement Company, 2 Market Street, San Francisco, was leased to the California Rock and Gravel Company, 1800 Hobart Building, San Francisco (Logan, 1947, p. 225). At the present time this firm operates a quarry at this site for the production of limestone, which is used chiefly in sugar refineries.

      Figure 2. Old limestone quarry in the south Cool-Cave Valley deposit; view north from State Highway 49.

      Old limestone quarry in the south Cool-Cave Valley deposit

      General Geology (of Cool-Cave Valley)

      The general trend of the rock units is north to northwest. The rocks of the region consist of a series of dynamothermally metamorphosed marine sediments of the Calaveras group and metavolcanic rocks, some of which probably belong to the Calaveras group and some of which probably do not.

      "The Calaveras group, of which the limestone has been considered as part, makes up the bulk of the Paleozoic part of the bedrock of the Sierra Nevada. For a long time the Calaveras group was considered to be Carboniferous in age; however, recent work has caused a number of investigators to believe that it includes a greater part of the Paleozoic section than just the Carboniferous (Taliaferro, 1943, p. 280). Stratigraphic relations of the limestone with other members of the Calaveras group are not clear in many areas.

      Figure 7. Geologic map of the Cool-Cave Valley limestone.

      Geologic map of the Cool-Cave Valley limestone.

      Rock Units (of Cool-Cave Valley)

      "Metavolcanic Rocks. In the immediate area of the Cool-Cave Valley limestone, the enclosing rock consists chiefly of metamorphosed volcanic rocks, green schist and massive unlaminated greenstone being the most abundant. Moderately resistant as compared with the other rocks of the region, the greenstone occurs in bold massive outcrops. Massive blocky greenstone is most common east of the Cool-Cave Valley limestone whereas green schist is common to the west. Green schist is well exposed in road cuts in the vicinity of the State Highway 49 bridge over the Middle Fork of the American River.

      "Where fresh, the massive greenstone is dull green to greenish-brown while the green schist is brilliant green. Both weather readily, first to a dull red or brown and then to a red soil.

      "The greenstone and green schist have apparently derived from a series of fine-grained basic volcanic rocks, many of them tuffaceous. They are composed chiefly of chlorite with varying amounts of epidote, actinolite-tremolite, plagioclase, hornblende, zoisite, and small amounts of iron oxide and pyrite. Calcite is sometimes present in veinlets and cavities. Prophyroblastic textures are common.

      "Amphibolite. Two miles west of the Cool-Cave Valley limestone is a 2000-foot-wide bed of hornblende-plagioclase amphibolite. It is massive to schistose and varies from a light-colored plagioclase-rich variety to a dark-green variety composed chiefly of hornblende.

      "Cutting across the limestone in the north end of Mountain Quarries at a small angle to the elongation of the lens is a 45-foot wide dikelike mass of dark grayish-green rock containing numerous amygdules of white calcite. It is badly-sheared porphyritic amygdaloidal basalt composed of calcite amygdules and pseudomorphs of intermeshed calcite and relict plagioclase set in a dark fine-grained groundmass of chlorite and iron oxide.

      "Diorite Porphyry. Both the limestone and the metavolcanic rocks in the vicinity of the limestone have been intruded by a number of diorite porphyry and quartz diorite porphyry dikes. they cut the limestone and metavolcanic rocks at small-angles both in dip and strike. The dikes are light to medium gray in color and are composed of phenocrysts of plagioclase, epidote, chlorite and iron oxide. Quartz may or may not be present. Much secondary calcite and usually small amounts of pyrite are present.

      "Serpentine. Serpentine is widely distributed throughout the area. the largest serpentine body in this region crops out for about 1500 feet along an old railroad right-of-way on Robie Point in eastern Auburn. It is derived from basic intrusive rock, both the olivine and pyroxene have been altered to light and dark serpentine. There are many small serpentine bodies in the vicinity of the limestone, which have been altered to light iron oxide-stained talc.

      "Metasedimentary Rocks. Metasedimentary rocks of the region include slate, chert, sheared sandstone and conglomerate, and limestone. All of the metasediments in the general area of the Cool-Cave Valley deposit have been considered to be part of the Calaveras group by Lindgren (1894). The Clipper Gap formation, part of the Calaveras group named by Lindgren, crops out in the southwestern portion of the adjoining Colfax quadrangle and is an extension of the series of metasediments in this area.

      "Chert in this area varies from light to dark gray in color and is in places stained black with manganese oxide. The chert occurs in thin lenticular beds that are often contorted near the surface. Slate occurs in irregular beds and varies from a grayish cherty variety to a nearly black clayish variety. Also present in appreciable amounts are argillaceous sandstone, arkosic sandstone and fine- to coarse-grained conglomerate, all of which have undergone varying degrees of shearing.

      "A wide belt of these metasediments are exposed along the Southern Pacific Railroad 3 miles to the north of the Cool-Cave Valley limestone deposit. A branch of this belt extends south to just east of the State Highway 49 bridge over the Middle Fork of the American River about one mile west of the limestone. Another wide belt of metasediments, which joins those to the north, extends in a general northwest direction about 2 miles east of the limestone.

      Figure 5. Contact between limestone and a mass of amygdaloidal basalt that cuts across the limestone in the north end of Mountain Quarries.

      Contact between limestone and a mass of amygdaloidal basalt

      Figure 6. Quartz diorite porphyry dikes cutting limestone in Mountain Quarries; camera facing north toward Auburn-Forest Hill road.

      Quartz diorite porphyry dikes cutting limestone in Mountain Quarries

      Regional Geologic Structure (of El Dorado and Placer Counties)

      "Structure sections accompanying the U. S. Geological Survey folios that cover El Dorado and Placer County published during the period 1890-1900 indicate a regional homoclinal relationship of the stratified rocks of the basalt complex. Taliaferro (1943 pp. 285-286) in his studies along the Cosumnes River, which lies than 30 miles south of the Cool-Cave Valley limestone, has demonstrated that the relationships are far more complex and that the stratigraphy is complicated by large and small isoclinal folds and by major faults. Although detailed mapping on a regional scale was beyond the scope of this study, mapping of several strips across the regional trend of the formations indicated that similar structural conditions exist in the Cool-Cave Valley vicinity. Although slaty cleavage, schistosity and often major joint patterns tend to be parallel to the bedding in stratified rocks of the region, the relationship does not hold at crests and troughs of folds; cleavage and schistosity tend to be much more prominent than bedding. Interpretation of structure is further complicated by a lack of continuous distinctive beds and by a lack of time markers.

      Cool-Cave Valley Limestone

      "The large lenses comprising the Cool-Cave Valley deposit extend in a north direction for a distance of approximately 1 ¾ miles.

      "The large northern lens, which is crossed by the Middle Fork of the American River at the northern end, is about 5500 feet long and averages 400 feet in width. Diamond drilling done by the Pacific Portland Cement Company showed this lens to extend to a depth of at least 800 feet below the original land surface of Mountain Quarries. (Tucker, 1916). The southern lens, which is crossed by State Highway 49, is 2000 feet long and nearly 600 feet wide in the middle.

      "Being relatively resistant to erosion, the limestone stands out prominently from the surrounding metavolcanic rocks. The limestone is partially to completely recrystallized and is dense and tenacious. When fresh it is dark bluish gray to almost black in color. When weathered, it is light bluish gray. The limestone is generally even-grained, the individual crystals varying from 1 to 3 mm in diameter. A fetid odor of hydrogen sulfide is emitted when a fresh surface is hammered. Chemical weathering is most prominent along the joints. Small solution caves containing coarse crystalls (sic) of secondary aragonite are common along joints in the limestone.

      "Although much of the limestone is completely recrystallized, a small mount of fossil debris is composed partly of coral and crinoid fragments of indeterminate age. Small amounts of pyrite are present in the limestone with the fossil debris.

      "A considerable part of the Cool-Cave Valley limestone mass was originally composed of organic debris, much of it being of crinoid and coral fragments. Part of the mass may have been chemically precipitated. The original source of calcium carbonate may have been volcanic in part as suggested by the almost universal association of limestone with metavolcanic rocks in this area.

      "At the north end of the Mountain Quarries some of the exposed surfaces of the limestone have a fluted appearance which is caused by a series of parallel grooves varying from one to several feet apart and one to several inches in depth. These grooves are parallel to the strike and were apparently formed on slip surfaces.

      Figure 9. Jointing in the limestone of Mountain Quarries.

      Jointing in the limestone of Mountain Quarries.

      Figure 10. Jointing in the limestone in the south Cool-Cave Valley deposit.

      Jointing in the limestone in the south Cool-Cave Valley deposit

      Structure of the Limestone

      "Strike of bedding and schistosity in the northern lens varies from north to N. 15 W. Dip is both to the east and west and ranges from 75 degrees to vertical. Parallel jointing is prominent. The joint planes of the principal series of joints are 1 to 15 feet apart and have a strike nearly perpendicular to that of the bedding. Dip of the joints is north and ranges from 20 to 35 degrees. Secondary joints if present, are either parallel to the strike of the bedding or are perpendicular to the bedding and dip south.

      "Bedding and schistosity of the southern lens strike approximately N. 15 E. and dip 75 to 85 degrees northwest. As in the northern lens, joints are nearly perpendicular to the strike of the bedding and schistosity and dip 20 to 35 degrees northeast.

      "No definite conclusion can be reached in regard to the precise position of the limestone lenses in the stratigraphic sequence or to the exact structural relationship between the limestone and the enclosing rocks. However, several interpretations are possible based on the following observations:

      "1. In some places differential movement between the limestone and the enclosing greenstone is plainly indicated; in others there is no evidence of differential movement. In places where there have been differential movements their magnitude cannot be measured. In and adjacent to the glory hole at Mountain Quarries, a quartz diorite dike cuts diagonally across the limestone-greenstone contact. It has not been displaced at the contact showing that any movement which might have taken place along the contact would have occurred prior to the emplacement of granitic rocks in Upper Jurassic time.

      "2. The Cool-Cave Valley deposits are bordered entirely by greenstone as are several smaller lenses exposed along the Forest Hill road and elsewhere in the area. Other limestone lenses in the general area are bordered entirely or partly by other metasediments such as slate, mica schist, meta chert, etc.

      "3. The Cool-Cave Valley limestone bodies occupy a median position between two belts of metasediments. One and a half miles northwest of the deposits along the canyon of the North Fork of the American River, metasediments of the Clipper Gap formation are interfolded with greenstone. The area distribution of the wedge-shaped salients, as seen on the accompanying map, strongly suggests a succession of steeply pitching, large-scale isoclinal folds. This relationship is well seen on a smaller scale in roadcuts along the south side of the North Fork Dam road in the extreme northwest corner of sec. 1, T. 12 N., R. 8 E., M.D.B. and M. There, metavolcanics are stratigraphically below metasediments in the crest of an anticline.

      "4. At the north end of Mountain Quarries the limestone is crossed by a tabular mass of sheared, altered, amygdaloidal, basic volcanic rock similar in character to some facies of the enclosing greenstone. The amygdaloidal mass transgresses slightly the regional trend of the limestone lens south of the American river and north of the river a similarly trending mass is found a few feet within the enclosing greenstone. The amygdaloid has obviously been deformed with the limestone prior to emplacement of the dioritic dikes.

      "Three possible structural interpretations are:

      "1. If the displacement along the contact between the limestone and greenstone is interpreted as having been of great magnitude, then the limestone could have reached its present position by major faulting, plastic flow or a combination of both prior to Upper Jurassic time.

      "2. If displacement along the contact and presence of isoclinal folding are discounted as being of minor importance only and the stratigraphic sequence is interpreted as homoclinal as shown on the folios, then the limestone could be interpreted simply as a lenticular member interbedded with the enclosing greenstone.

      "3. The relative position of the limestone lenses with respect to the position of the greenstone and the Calaveras group metasediments suggests a major structure with the limestone lenses lying roughly along the axis of that structure. However, since the relative ages of the greenstone, Calaveras group, and limestone are uncertain, judgment of such a structure as anticlinal or synclinal is not possible.

      Analyses of the Limestone (in Cool-Cave Valley)

      "Nearly all of the limestone in the Cool-Cave Valley deposit is high in calcium carbonate and low in magnesium carbonate. A total of 45 samples were taken from both lenses Samples of fresh limestone, varying from 2 to 4 pounds in weight, were taken at regular intervals across the strike of the lenses and several composite samples of small chips were taken along the margins of the southern lens.

      "All but one of the eleven samples taken from the north portion of the north lens north of the Middle Fork of the American River contained more than 98 percent calcium carbonate. Three of the eleven samples contained slightly more than 1 percent while the other eight contained less than 1 percent magnesium carbonate.

      "Many samples were taken in Mountain Quarries, both from along the margins of the lens and from near where the limestone is cut by diorite porphyry dikes and amygdaloidal basalt. Other than two samples taken next to the limestone-amygdaloidal basalt contact, which ran slightly over 90 percent calcium carbonate and about 5.5 percent insoluble material, all others varied from about 96.4 to 98.6 percent calcium carbonate, .5 to 1.6 percent magnesium carbonate and 1 percent or less insoluble. Five samples taken from the strike at the southern end of the north lens averaged 97.6 percent calcium carbonate and 1.1 percent magnesium carbonate.

      "The following are analyses supplied by the California Rock and Gravel Company of four limestone samples from lots shipped from their quarry in the central portion of the north lens.

      "Five samples taken across the north end of the south lens averaged 96.8 percent calcium carbonate and 0.77 percent magnesium carbonate. Sample number 10, a composite sample taken along the northwest margin of the lens which contained 93.8 percent calcium carbonate and 4.6 percent insoluble material, is not believed to be truly representative of the deposit as the limestone is deeply weathered in this part of the deposit. Four samples taken from the southern end of the south Cool-Cave Valley deposit averaged 97.1 percent calcium carbonate and 1.2 percent magnesium carbonate.

      "In general, the deposit is nearly uniform in composition. There are no noticeable changes in composition across the strike of the lenses. Apparently, there has been very little contamination from outside sources. Except in a few places at the extreme outer edge of the lenses and where the limestone has been deeply weathered, composition of the deposit is 97 to 99 percent calcium carbonate.

      Figure 11. North end of the Cool-Cave Valley deposit on the north side of the Middle Fork of the American River; camera facing north.

      North end of the Cool-Cave Valley deposit on the north side of the Middle Fork of the American River

      Bibliography (for the Cool-Cave Valley Limestone)

      Aubury, Lewis E., 1902, El Dorado County: California Min. Bur. Register of Mines and Minerals, p. 17.

      Aubury, Lewis, E., 1906, The structural and industrial materials of California: California, Min. Bur. Bull. 38.

      Bowen, O. E., Jr., and Crippen, R. A., Jr., 1948, Geologic maps and notes along Highway 49: California Div. Mines Bull. 141, p. 70, 73, 80.

      Crawford, J. J., 1894, California Min. Bur. Rept. 12, p. 391-392.

      Crawford, J. J., 1896, California Min. Bur. Rept. 13, p. 628.

      Hamilton, Fletcher, 1919, California Min. Bur. Rept. 15, p. 304.

      Hanks, Henry G., 1884, California Min. Bur. Rept. 4, p. 107.

      Jerkins, Olaf P., 1938, Geologic map of California, scale 1:500,000: California Div. Mines.

      Knopf, Adolph, 1929, The Mother Lode system of California: U. S. Geol. Survey Prof. Paper 157, p. VII.

      Laizure, C. McK, 1927, California Min. Bur. Rept. 23, p. 208.

      Laizure, C. McK., 1929, California Min. Bur. Rept. 25, p. 251.

      Lindgren, Waldemar, 1894, U. S. Geol. Survey Atlas, Sacramento folio (no. 5), 12 pp., 4 maps.

      Lindgren, W. and Turner, H. W., 1894, U. S. Geol. Survey Atlas, Placerville folio (no. 3), 9 pp., 4 maps.

      Logan, C. A., 1921, California Min. Bur. Rept. 17, p. 432.

      Logan, C. A., 1924, California Min. Rept. 20, p. 8.

      Logan, C. A., 1926, California Min. Bur. Rept. 22, pp. 442-443.

      Logan, C. A., 1927, California Min. Bur. Rept. 23, pp. 281-282.

      Logan, C. A., 1938, California Div. Mines Rept. 34, pp. 277, 280.

      Logan, C. A., 1947, Limestone in California: California Div. Mines Rept. 43, pp. 224-226, 231-233.

      Taliaferro, N. L., 1943, The Calaveras: California Div. Mines Bull. 125, pp. 280-282.

      Tucker, W. B., 1919, Mountain Quarries: California Min. Bur. Rept. 15, p. 304.

      Young, George J., 1925, Quarrying limestone by glory holes: Eng. and Min. Jour.-Press, Vol. 120, pp. 13-16.

    • Cool-Cave Valley (Coswell-Cave Valley) Deposit circa 1955 (From "Mines and Mineral Resources of El Dorado County, California," California Journal of Mines and Geology, Vol. 52, No. 4, October 1956, California Division of Mines. Used with permission, California Department of Conservation, California Geological Survey.)

      "Cool-Cave Valley (Coswell-Cave Valley) Deposit. Location: secs. 6, 7, and 18, T. 12 N., R. 9 E., M. D., 4 miles east of Auburn on the south side of the Middle Fork of the American River. Ownership: South 2/3, Henry Cowell Lime Cement Company, 2 Market Street, San Francisco; north 1/3, Ideal Cement Company, 310 Sansome Street, San Francisco.

      Figure 23. Limestone quarry of California Rock and Gravel Company. Camera facing north. (From "Mines and Mineral Resources of El Dorado County, California," California Journal of Mines and Geology, Vol. 52, No. 4, October 1956, California Division of Mines. Used with permission, California Department of Conservation, California Geological Survey.)

      Limestone quarry of California Rock and Gravel Company

      Fig. 39. The California Rock and Gravel Company limestone quarry on the south side of the Middle Fork of the American River east of Auburn. Photo by Olaf P. Jenkins. (From Geologic Guidebook Along Highway 49 - Sierran Gold Belt: The Mother Lode Country, Bulletin 141, Olaf P. Jenkins, Chief, California Division of Mines, San Francisco, California, 1949. Used with permission, California Department of Conservation, California Geological Survey.)

      The California Rock and Gravel Company limestone quarry on the south side of the Middle Fork of the American River

      "The largest limestone deposit in the county, the Cool-Cave Valley deposit has been a major source of limestone for the cement, lime, and beet-sugar industries for many years. It consists of two north-trending lenses. During the 1880's and 1890's, limestone was quarried from the south lens and burned in stone lime kilns (Clark, 1954, p. 441). Ruins of these old kilns are near State Highway 49. From 1910 to 1940, the Pacific Portland Cement Company operated an extensive quarry at the north end of the north lens by the Middle Fork of the American River. This deep quarry was known as Mountain Quarries. Limestone was sent through a crushing and sizing plant and shipped over a company-owned railroad to Auburn and then to the Pacific Portland Cement plant in Solano County or to beet sugar refineries. In 1942, the quarry was abandoned and the railroad dismantled.

      "In 1946, the south portion of the north lens, south of Mountain Quarries, was leased by the California Rock and Gravel Company. This concern produces limestone for use in beet-sugar refining and lime manufacturing. A detailed study recently was made of this deposit, the results of which were published in the California Journal of Mines and Geology, vol. 50, July-October 1954, pp. 439-465.

      "The deposit consists of high-calcium bluish-gray crystalline limestone. The north lens, which is cut by the Middle Fork of the American River near the north end, is about 5500 feet long and has an average width of 400 feet. It was worked to a depth of nearly 800 feet in Mountain Quarries. The south lens, which is crossed by State Highway 49, is 2,000 feet long and nearly 600 feet wide in the middle. A number of samples taken from both lenses averaged more than 97 per cent CaCO3 and less than 1 percent MgCO3 (Clark, 1954, p. 454). Country rock is green schist and massive greenstone. Both lenses are cut by dikes of medium-grained diorite and quartz diorite. The limestone is well jointed.

      "At the California Rock and Gravel Company quarry in the south-central portion of the north lens, limestone is mined by several methods. In 1946 and 1947, it was quarried by benching with 30-foot wagon drill holes. From 1948 to 1952, it was mined with 'coyote' holes where adits were driven perpendicular to the quarry face and branches drive perpendicular to the adits. These were loaded with dynamite and an entire year's supply of limestone was dislodged with one blast (Clark, 1954, p. 458). At the present time large benches and 100-foot vertical wagon drill holes are used. About six months' supply is dislodged in one blast. Large fragments remaining from the blast are broken with a drop ball. In the fall of 1955, a new quarry north of the plant was being developed.

      "Broken stone from the quarry is trucked to nearby crushing and screening plant. Coarse and medium sizes are trucked to Auburn and shipped by rail to beet-sugar refineries in the Sacramento and San Joaquin Valleys. The finer sizes are trucked to the Diamond Springs Lime Company for lime manufacturing. Until 1954, this concern also supplied limestone to the Vertin Lime Company plant at Rattlesnake Bridge. Undersize is stockpiled and sold as road metal. Twenty-seven men work at the quarry and plant.

      Another limestone lens is located about one mile to the west on the Middle Fork of the American River. It also is composed of bluish-gray high-calcium limestone (Clark, 1954, p. 460). The lens, which strikes northwest, is 450 feet long and 50 feet wide. It was worked many years ago, and the stone was burned in a stone lime kiln at the north end."

    • Auburn (east of), El Dorado County, California – Limestone Deposit West of the Cool-Cave Valley Limestone Deposit (Limestone) (Excerpt from "The Cool-Cave Valley Limestone Deposits, El Dorado and Placer Counties, California," by William B. Clark, Junior Mining Geologist, California Division of Mines, California Journal of Mines and Geology, Vol. 50, Nos. 3 and 4, July-October 1954, pp. 439-466. (Used with permission, California Department of Conservation, California Geological Survey.)

      "Approximately one mile west of the Cool-Cave Valley deposit on the south side of the Middle Fork of the American River, about 2000 feet southeast of the State Highway 49 bridge, is a small northwest-trending lens of dark bluish-gray limestone enclosed in metasediments. It is about 450 feet long and 50 feet wide…."

      The following information is taken from "Table 1. Limestone deposits in the general area of the Cool-Cave Valley limestone," (circa 1954) on pages 462 and 463:

    • (No. on map, Plate 3) 10; (Deposit) Limestone deposit one mile west of Cool-Cave Valley deposit near State Highway 49 bridge; (Owner) Pacific Portland Cement Company, 417 Montgomery Street, San Francisco; (Location) Sec. 12, T. 12 N., R. 8 E., M.D.

    • Auburn (east of), El Dorado County, California - Limestone Quarries North of Cool (From Geologic Guidebook Along Highway 49 - Sierran Gold Belt: The Mother Lode Country, Bulletin 141, Olaf P. Jenkins, Chief, California Division of Mines, San Francisco, California, 1949. Used with permission, California Department of Conservation, California Geological Survey.)

      "A mile and a half north of Cool, a group of limestone quarries can be seen on the north side of the highway. Limestone was first quarried and burned there some 40 or 50 years ago by the Cave Valley Lime Company. One of the kilns can be seen close to Highway 49 near the abandoned quarry, a quarter of a mile south of the road turnoff to the main workings. The kiln walls were made of limestone lined with greenstone. Local wood was used to fire the kilns. The present operators of the quarry, the California Rock and Gravel Company, quarry and crush the limestone for conversion into lump lime but do not produce either lime or cement themselves."

  • Auburn (4 miles east of), El Dorado County, California - the Cool-Cave Valley Mine (Limestone) (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document. The following quotation is used with permission.)

    "The Cool-Cave Valley (Coswell-Cave Valley) Mine is a limestone quarry on the largest limestone deposit in El Dorado County. It is located 4 miles east of Auburn on the south side of the Middle Fork of the American River. The two lenses of high purity (97% calcium carbonate) limestone at this location measure 5500 feet by 400 feet and 2000 feet by 600 feet. Their depth is unknown, but they have been worked as deep as 800 feet at the north end. No one knows for sure when limestone was first removed from this location, but during the 1880's and 1890's, limestone was quarried from the southern part of the deposit and burned in stone lime kilns for the production of cement. From 1910 - 1940 the Pacific Portland Cement Company operated a massive quarry at the north end of the deposit, by the Middle Fork of the American River. This deep quarry, known as Mountain Quarries, produced enormous amounts of limestone that was crushed, sized and shipped over a company owned railroad to Auburn and then to their plant in Solano County or beet sugar refineries (limestone of very high purity is necessary for the production of beet sugar). In 1942 the quarry was abandoned and the railroad dismantled. Later, this portion of the quarry would be reactivated and later, be acquired for Auburn Reservoir. The southern portion of this quarry is still mined with the limestone being used for beet-sugar refining and other purposes. Mining at this location has been by many methods, one interesting one called "coyote" holes. Several adits were driven into the quarry face and then branches perpendicular to it. These were loaded with dynamite and a whole years supply of limestone was dislodged in one huge blast."

  • Auburn (northeast of), El Dorado County, California - Mountain Quarries (Limestone) (Excerpt from "Limestone in California," by Clarence A. Logan, California Journal of Mines and Geology, Vol. 43, No. 3, July 1947, California Division of Mines, San Francisco, California, pp. 175-357. Used with permission, California Department of Conservation, California Geological Survey.)

    "Mountain Quarries (Pacific Portland Cement Company, 417 Montgomery Street, San Francisco). This large quarry in sec. 6, T. 12 N., R. 9 E., on the south slope of the canyon of American River, was for many years a main source of supply of limestone for making cement and for use in the sugar and steel industries. Production started in 1910 and continued through 1940. The crude limestone was hauled out over the company's own railroad 7 miles long connecting with the Southern Pacific a mile west of Auburn. Late in 1942, the rails on this line and most of the machinery at the quarry, as well as the locomotives used for hauling stone, were removed and sold, and all work ceased.

    This was the largest limestone quarry in northern California and has been frequently described. The deposit is a large lens of gray limestone of which a substantial part has been eroded by Middle Fork of American River in forming its canyon. If the 1500-foot contour is taken as the approximate present level of the Cretaceous peneplain in that region, the river has cut a broad V-shaped valley nearly at a right angle to the schistosity of the amphibolite schist in which the limestone lies, to a depth of about 800 feet below the dissected peneplain, of which remnants have remained under coverings of auriferous gravel on hills in the region. Cutting of the canyon was apparently not at a uniform rate, and was faster in the lower, modern section. The limestone outcrops over the entire vertical range and has been found by diamond drilling to extend still deeper.

    "The quarry was opened near the river level and the upper bench was carried to the property line on the south. The photographs show the character of the deposit. The dike seen in the picture of the upper workings near the south line is of augite porphyrite. This body of limestone extends across the river but the part in Placer County is small. It appears there is a rather dark-gray stone, which is medium grained and tough and is a very high-grade high-calcium limestone."

    Plate 27-A. Remainder of Limestone Outcrop - Mountain Quarries deposit near Cool, El Dorado County. Glory holes in this deposit supplied limestone at the rate of more than 1,000 tons daily for many years.

    Remainder of Limestone Outcrop - Mountain Quarries deposit near Cool, El Dorado County

    Plate 27-B. Top of Glory Hole - Mountain quarry of Pacific Portland Cement Company. A diabase dike 5 to 6 feet wide (marked "x") intrudes the limestone. (left side of photo)

    Top of Glory Hole - Mountain quarry of Pacific Portland Cement Company

    • Auburn (northeast of), El Dorado County, California – Mountain Quarries (Limestone) (Excerpt from Report XV of the State Mineralogist, Mines and Mineral Resources of Portions of California, Chapters of State Mineralogist's Report Biennial Period 1915-1916, Part III. The Counties of El Dorado, Placer, Sacramento, Yuba, California State Mining Bureau, 1919, pp. 271-459. Used with permission, California Department of Conservation, California Geological Survey.)

      "Mountain Quarries, owned by the Pacific Portland Cement Company, F. G. Drum, president; F. E. Erline, secretary; offices, 832 Pacific Bldg., San Francisco.

      "The Mountain Quarries are situated 6 miles northeast of Auburn on the ridge south of the middle fork of the American River. The limestone occurs in the form of a lens in amphibolite schist. The general strike of this lens is north and south. The width of the deposit is from 300' to 400'. Its depth has been proven to be 800 feet by means of diamond drill holes. The limestone is worked from an open quarry, the broken material falling through a 600' shaft to ore bins in a tunnel, from which it is trammed a distance of 620 feet to storage bins located on the line of the Southern Pacific Railroad. The broken rock is shipped to the company's cement plant located at Cement, near Fairfield, Solano County. About 1200 tons a day are shipped from the quarries to this plant. 100 men are employed."

  • View of quarry and loading bins, Mountain Quarries, El Dorado County. Pacific Portland Cement Co., owners. Photo by C. A. Waring.

    View of quarry and loading bins, Mountain Quarries, El Dorado County

    :

    View of storage bins of Mountain Quarries. El Dorado County. Owned by the Pacific Portland Cement Company. Photo by C. A. Waring.

    View of storage bins of Mountain Quarries. El Dorado County

    • Auburn (northeast of), El Dorado County, California – Mountain Quarries (Limestone) (Excerpts from "The Cool-Cave Valley Limestone Deposits, El Dorado and Placer Counties, California," by William B. Clark, Junior Mining Geologist, California Division of Mines, California Journal of Mines and Geology, Vol. 50, Nos. 3 and 4, July-October 1954, pp. 439-466. (Used with permission, California Department of Conservation, California Geological Survey.)

      Quarrying and Milling Operations (at Mountain Quarries Cool-Cave Valley Limestone Deposit)

      "Limestone at Mountain Quarries was quarried by the glory hole method. Three glory holes were connected by raises from an 1800-foot south-extending adit. The adit entered the hillside at a point about 70 feet above the river. The glory holes have vertical sides and have been worked to a depth of about 600 feet. Limestone was quarried to within a few feet of the edge of the lens. This practice prevented the walls from caving as the limestone is much more rigid and tenacious than the surrounding volcanic rocks. The parallel joints in the limestone were an aid in quarrying operations.

      "Overburden was removed by steam shovels. Stone was then blasted from the quarry faces, dumped down the raises to chutes and then to 6-ton cars in the adit. The cars were then trammed out the adit to the crushing and sizing plant. Before crushing, it was hand-sorted to remove the dike rock and other foreign material. the stone was then fed to a gyratory rock crusher and then to trommels where it was washed and sorted. It was conveyed to railroad cars and shipped over a seven-mile company-owned railroad to Auburn.

      "Three sizes; 2 ½-inch, plus 2 ½-inch minus 4-inch, and plus 4, minus 8-inch were produced. The 2 ½-inch rock was shipped to the Pacific Portland Cement Company cement plant in Solano County while the coarser sizes were shipped to sugar refineries (Young, 1925). Peak production varied from 1200 to 1500 tons of limestone per day. About 140 men were employed at the quarry and plant.

    Figure 3. Mountain Quarries 1953; view south across the Middle Fork of the American River.

    Mountain Quarries 1953; view south across the Middle Fork of the American River

    Figure 4. Mountain Quarries on the Middle Fork of the American River as seen from the Auburn-Forest Hill road in 1940 showing crushing plant and loaded train.

    Mountain Quarries on the Middle Fork of the American River

    "In 1946, the central portion of the northern lens south of Mountain Quarries, owned by the Henry Cowell Lime Company, 2 Market Street, San Francisco, was leased by the California Rock and Gravel Company, 1800 Hobart Building, San Francisco. For a time this property was worked for them under contract by E. B. Bishop. Production during this period was several hundred tons per day (Logan, 1947, p. 225). Since 1947, the California Rock and Gravel Company has operated the quarry. Since 1948, the 'coyote hole' method of quarrying has been employed. A quarry face 65 feet high and more than 300 feet long is being worked. Near the base of the quarry 40-foot adits or 'coyote holes' 80 to 100 feet apart are driven perpendicular to the quarry face. At the ends of the adits 30-foot branches are driven perpendicularly or at large angles from the line of the adit so that they end about 20 feet from the end of the adjacent branch. The adits and branches are then loaded with 40 percent Atlas dynamite. In 1952 approximately 18 tons of dynamite were used for this operation.

    "The entire dynamite charge is then shot electrically. About 150,000 tons are dislodged in the single blast, enough to sustain continuous plant operation for an entire year.* Secondary breaking of stone in the quarry is done with a 4-ton steel drop ball suspended from a crane. Power shovels then load the limestone into dump trucks which deliver it to the crushing plant about 1000 feet north of the quarry.

    (* Page 458 footnote: Kelly, George, personal communication, 1952.)

    "At the crushing plant the limestone is delivered to an electrically operated 30- by 42-inch primary jaw crusher, set at 7 ½ inches. The rock then passes by belt conveyor to a trommel with 6-inch square holes. Oversize goes to a secondary crusher while undersize is delivered by inclined belt conveyor to a three-deck inclined trommel on top of three loading bins. Three sizes: plus 4- by minus 6-inch square holes. Oversize goes to a secondary crusher while undersize is delivered by inclined belt conveyor to a three-deck inclined trommel on top of three loading bins. Three sizes: plus 4- by minus 6-inches, plus 2- by minus 4-inches, and plus ½-minus 2-inches are classified into the bins. The minus ½-inch rock is delivered by belt conveyor to a stockpile east of the crushing plant.

    "The coarsest and middle sized stone in the bins is trucked to Auburn where it is loaded into railroad cars and shipped to beet sugar refineries in the Sacramento and San Joaquin Valleys. The finest binned stone is trucked to the Hughes Vertin Lime Company plant at Rattlesnake Bridge where lime is manufactured in inclined rotary kilns. Occasionally, some of the plus ½- by minus 2-inch limestone is shipped to steel plants in the San Francisco Bay area where it is used as a flux in open-hearth steel furnaces. Nearly all of the undersize rock, not binned, is sold as road metal.

    Figure 8. North end of Mountain Quarries, camera facing north. To left a dikelike mass of amygdaloidal basalt crosses the limestone mass. To right, grooves in limestone give a fluted appearance.

    North end of Mountain Quarries, camera facing north

    Figure 5. Contact between limestone and a mass of amygdaloidal basalt that cuts across the limestone in the north end of Mountain Quarries.

    Contact between limestone and a mass of amygdaloidal basalt

    Figure 6. Quartz diorite porphyry dikes cutting limestone in Mountain Quarries; camera facing north toward Auburn-Forest Hill road.

    Quartz diorite porphyry dikes cutting limestone in Mountain Quarries

    Figure 9. Jointing in the limestone of Mountain Quarries.

    Jointing in the limestone of Mountain Quarries.

    Figure 13. Mountain Quarries, camera facing south. The quarry walls are nearly 600 feet high.

    Mountain Quarries, camera facing south

    Figure 14. California Rock and Gravel Company quarry; camera facing north. Fall, 1952.

    California Rock and Gravel Company quarry

    Figure 15. California Rock and Gravel Company quarry in Spring, 1953.

    California Rock and Gravel Company quarry in Spring, 1953

    Figure 16. East face of California Rock and Gravel Company Quarry near the main entrance.

    East face of California Rock and Gravel Company Quarry

    Figure 17. California Rock and Gravel Company plant. Quarry is out of view to right.

    California Rock and Gravel Company plant

    Figure 18. Sizing plant and loading bins at the California Rock and Gravel Company plant.

    Sizing plant and loading bins at the California Rock and Gravel Company plant

    Figure 19. Crushing plant and trommel at the California Rock and Gravel Company plant.

    Crushing plant and trommel at the California Rock and Gravel Company plan

    Estimated Reserves (of Mountain Quarries)

    "It is estimated that the northern portion of the north lens, north of the Middle Fork of the American River, contains 1,125,000 tons of limestone per 100 feet of depth. The northern lens south of the river is estimated to contain 11,250,000 tons of limestone per 100 feet of depth. This estimate excludes that portion of limestone which has already been removed from Mountain Quarries. The southern lens is estimated to contain 5,850,000 tons of limestone per 100 feet of depth. Estimated tonnages are based on the limestone having an approximate weight of 150 pounds per cubic foot.

  • Auburn (south of), El Dorado County, California – Mountain Quarry, El Dorado County, California.

    A railroad line was constructed by the Pacific Portland Cement Company in the early 1900s to connect their limestone operation to the main line of the westbound Southern Pacific in Auburn, California. It was called the "Mountain Quarry."

  • Auburn (south of) and east of Newcastle, El Dorado County, California – Rattlesnake Bridge AKA Alabaster Cave, AKA Rattlesnake Bar (Limestone & Kiln) (From The Structural and Industrial Materials of California, Bulletin No. 38, California, State Mining Bureau, San Francisco, California, 1906.)

    "Alabaster Cave, W. T. Holmes Lime Company, 24 Sacramento street, San Francisco, owner, is about 7 miles east of Newcastle, on the east side of the American River, and about three-fourths of a mile above the suspension bridge. It occurs in a crystalline, granular, white, and clouded white and blue limestone, which lies in a stratum about 50 feet thick, inclosed by mica-schists. The limestone layers are standing vertical and have a north and south strike parallel with the cleavage of the schist. It forms a bold outcrop on each side of a small cañon that cuts through it. The Alabaster cave from which the place is named is on the roadside on the north side of the canon. A lime quarry was opened on the hill immediately above it, and a stone kiln in which the lime was burned is on the roadside, but they have not been used for several years.

    "On the south side of the cañon and a few hundred feet from the cave is a large stack kiln, in which is burned the lime from the stone quarried just above it. This quarry has been worked to a depth of 50 feet, about 300 feet long, and to the full width of the limestone. The lime rock is brought on tram-cars to the top of the kiln, which stands on the hillside below the level of the quarry.

    "The stone at the above quarry is a compact, heavy, medium-coarse, crystalline limestone, free from impurities, except a few parallel bands of schist which are inclosed in it. Some of these schist bands are disintegrated to the depth of the quarry opening, and the rotten schist is easily separated from the limestone; but some of the schist is not disintegrated and is not so easily separated from the limestone, and hence causes some waste in the quarrying.

    "The stone is burned with wood in the kiln at the quarry and hauled in rawhide sacks by wagon 7 miles to Newcastle, on the Southern Pacific Railroad. It is mostly shipped to Sacramento and handled by the Sacramento Lime Company."

    • Auburn (south of), El Dorado County, California – Rattlesnake Bridge AKA Alabaster Cave Lime Quarry and Rattlesnake Bar (Limestone) (Excerpt from Report XV of the State Mineralogist, Mines and Mineral Resources of Portions of California, Chapters of State Mineralogist's Report Biennial Period 1915-1916, Part III. The Counties of El Dorado, Placer, Sacramento, Yuba, California State Mining Bureau, 1919, pp. 271-459.)

      "Alabaster Cave Lime Quarry. See our Bulletin 38, pp. 67-68. Situated 7 miles east of Newcastle, Placer County, on ridge southeast of the middle fork of the American River. The limestone lies in a stratum 50' thick enclosed by mica schist. The character is crystalline, granular, white, clouded white and blue limestone. Quarry 50' deep by 300' long, by 50' in width. Idle. W. T. Holmes Lime Company, Monadnock Bldg., San Francisco, owner

    • Auburn (south of), El Dorado County, California – Rattlesnake Bridge (Alabaster Cave) (Limestone Deposit) (From "The Cool-Cave Valley Limestone Deposits, El Dorado and Placer Counties, California," by William B. Clark, Junior Mining Geologist, California Division of Mines, California Journal of Mines and Geology, Vol. 50, Nos. 3 and 4, July-October 1954, pp. 439-466. (Used with permission, California Department of Conservation, California Geological Survey.)

      The following information is taken from "Table 1. Limestone deposits in the general area of the Cool-Cave Valley limestone," (circa 1954), pages 462 and 463:

      (No. on map, Plate 3) 14; (Deposit) Rattlesnake Bridge (Alabaster Cave); (Owner) C. L. Vertin, P.O. box 781, Salinas; (Location) Sec. 15, T. 11 N., R 8 E., M.D.; (References) Aubury 06:65-68; Tucker 19:304; Logan 21:432; 24:8; 26:442-443; 38:273-274; 47:222, 223-224.

    • Auburn (south of), El Dorado County, California - Rattlesnake Bridge AKA Alabaster Cave, AKA Rattlesnake Bar (Limestone & Kilns) (From "Mines and Mineral Resources of El Dorado County, California," California Journal of Mines and Geology, Vol. 52, No. 4, October 1956, California Division of Mines. Used with permission, California Department of Conservation, California Geological Survey.)

      "Rattlesnake Bridge (Alabaster Cave, Rattlesnake Bar) Deposit. Location: sec. 15, T. 11 N., R. 8 E., M. D., 1 mile east of Rattlesnake Bridge and 5 miles south of Auburn. Ownership: Semon Lime Company, Auburn, H. S. Dahlman, manager.

      "This limestone deposit, which also has been known as the Alabaster Cave deposit, has been worked intermittently since the 1860's by a number of concerns. There is an old stone lime kiln near the Rattlesnake Bridge road, which crosses the northern portion of the deposit. From 1930 to 1942, the Auburn Chemical Lime Company worked the deposit. Limestone from the south end of the deposit was treated at a crushing and sizing plant and sent through a lime plant. Much of the lime manufactured during the 1930's was sold to gold mines for use in cyanidation (Logan, 1947, p. 223).

      "From 1942 to 1954 there was little output from the quarries, as most of the limestone used at the plant was purchased from the California Rock and Gravel Company at Cool. From 1946 to 1948, the plant was operated by the Auburn Lime Products Company; from 1949 to 1954 by the Hughes-Vertin Lime Company; and from 1954 to 1955 by the Vertin Lime Company. In July 1955, the Semon Lime Company purchased the holdings and has operated the property since (H. S. Dahlman, personal communication, 1955). A new 7- x 110-foot rotary kiln and increased storage facilities were installed in 1953. In 1954, a new quarry was opened in the north end of the deposit. At present several grades of lime, quicklime, and hydrated lime are manufactured and marketed under the trade name 'Versatile.' Sized limestone also is sold."

      Figure 28. Semon Lime Company plant near Rattlesnake Bridge. Camera facing south.

      Semon Lime Company plant near Rattlesnake Bridge

      "The deposit is a lens of coarse-grained crystalline limestone ranging from white to bluish-gray in color. It strikes north and dips steeply east. It is about 4,000 feet long and 80 to 100 feet wide. Parallel joints are prominent; the principal joint planes strike west and dip steeply south. Most of the limestone is high in calcium carbonate (97 to 99 per cent) (H. S. Dahlman, personal communication, 1955). At one point there were a number of natural caves, which since have been quarried out. Country rock is amphibolite with small amounts of serpentine. There are several bands of amphibolite and chlorite schist up to several feet thick in the limestone, and these are troublesome in quarrying operations.

      "The deposit is developed by four quarries. Two are located south of the plant: one, 300 feet long, extends north from the south end of the deposit and the other 475 feet long extends south from the plant. They are up to 75 feet deep and 25 to 50 feet wide. These were the main source of limestone prior to World War II. An old quarry immediately north of the road was the source of the rock from the old stone limekiln.

      "Limestone is mined from 20-foot benches in a quarry about 300 feet long and 25 to 50 feet wide in the north end of the deposit. Wagon drills with 40 percent gelatin dynamite are used; large boulders are broken with jackhammers. Primary crushing is done in the quarry and secondary crushing and screening at the plant. The plus -inch stone is sent either to the new 7- by 110-foot oil-fired inclined rotary kiln or two older 4- by 60-foot kilns. Lime passes through a rotary cooler and into a storage bin for sacking, bulk loading, or hydration. Most of the lime produced is shipped to steel plants in the San Francisco Bay area or to the building-trades industry in the Stockton-Sacramento area. Minus -inch rock is screened into several sizes and sold as roofing granules, chicken grits, limestone flour, and road metal. Fifteen men work at the plant and quarry."

  • Auburn (five miles south of), El Dorado County, California - Rattlesnake Bridge (Alabaster Cave, Rattlesnake Bar) (Limestone) (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)

    This was a large limestone mine located one mile east of Rattlesnape Bridge, five miles south of Auburn. The site is now covered by Folsom Lake. The limestone was worked by various companies intermittently from the 1860s: Auburn Chemical Lime Co., Auburn Lime Products Co., Hughes-Vertin Lime Co., Vertin Lime Co., and Semon Lime Co. According to Mr. Noble's article, the "deposit, 4,000 feet long and 80 to 100 feet in width, is developed by four quarries, both north and south of the processing plant, up to 500 feet long, 25 to 50 feet wide and up to 75 feet deep."

  • Bowman (northwest of), Placer County, California – Cowell Limestone Deposit (Limestone & Kiln) (Excerpts from "Limestone in California," by Clarence A. Logan, California Journal of Mines and Geology, Vol. 43, No. 3, July 1947, California Division of Mines, San Francisco, California, pp. 175-357. Used with permission, California Department of Conservation, California Geological Survey.)

    "Cowell Deposit. Assessed to Henry Cowell Lime & Cement Company, 2 Market Street, San Francisco. This deposit is 2 ½ miles by good road northwest of Bowman, on the Southern Pacific Railroad. The deposit lies in a meadow traversed by a branch of Dry Creek, and has been eroded to the level of the surrounding land, and is in large part soil-covered. A shallow quarry with an area 90 by 90 feet and not over 6 feet deep was opened years ago and limestone was burned in an old kiln nearby. At a distance of 475 feet S. 20 W. from this pit, limestone is exposed in the creek-bed for 63 feet and there is another small exposure in the stream-bed 63 feet north. There are no other rock outcrops in this meadow which contains possibly 40 acres. It is probable that most of the deposit is concealed.

    "The limestone is dark gray and rather soft on the surface and apparently of good grade. Sinking would be required to open the deposit any farther."

    Analysis of limestone from Cowell deposit, by Abbot A. Hanks, Inc.

    Insoluble, 0.60 percent
    Ferric and aluminic oxides, 0.99 percent
    Calcium carbonate, 97.30 percent
    Magnesium carbonate, 1.09 percent

  • Browns Bar (near), El Dorado County, California - Browns Bar (Limestone) (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)

    "Browns Bar claim was a deposit of bluish-gray limestone near Browns Bar by the Middle Fork of the American River. It was apparently never worked."

  • Buckeye Canyon, El Dorado County, California -– Pacific Portland Cement Company (Limestone Deposit) (From "The Cool-Cave Valley Limestone Deposits, El Dorado and Placer Counties, California," by William B. Clark, Junior Mining Geologist, California Division of Mines, California Journal of Mines and Geology, Vol. 50, Nos. 3 and 4, July-October 1954, pp. 439-466. (Used with permission, California Department of Conservation, California Geological Survey.)

    (No. on map, Plate 3) 3; (Deposit) Buckeye Canyon; (Owner) Pacific Portland Cement Company, 417 Montgomery Street, San Francisco; (Location) Sec. 34, T. 13 N., R. 9 E., M.D.

  • Chili Bar, El Dorado County, California - the Buck Mine (Slate) (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)

    "The Buck Mine was a slate mine adjacent to the present Chili Bar slate mine. It was active in the 1880's."

  • Chili Bar (one-half mile north of), El Dorado County, California - the Losh Mine (Slate) (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)

    "The Losh Mine was a slate mine located one-half mile north of Chili Bar. During the years 1890, 1921-24 and 1937, dimension slate (blackboards, table tops, paving stones, etc.) was produced from an open pit 50 feet deep and 40 feet wide."

  • Chili Bar, El Dorado County, California – Pacific Minerals Co., Ltd. (Slate) (Excerpts from "California Mineral Commodities in 1951," California State Division of Mines, California Journal of Mines and Geology, pp. Vol. 50, No. 1, January 1954, pp. 59-147. Used with permission, California Department of Conservation, California Geological Survey.)

    (Operator) Pacific Minerals Co., Ltd. (granules, filler); (Address) 337-10th St., Richmond; (Location) Chili Bar.

  • Chili Bar (opposite), El Dorado County, California – the San Francisco Slate Company Quarry (Slate) (Excerpts from Slate Deposits and Slate Industry of the United States, Bulletin No. 275, by T. Nelson Dale with sections by E. C. Eckel, W. F. Hillerbrand, and A. T. Coons, "Slate Deposits and Industry of the United States - California, by Edwin C. Eckel, pp. 56-59, Department of the Interior, United States Geological Survey, Washington: Government Printing Office, 1906.)

    "San Francisco Slate Company quarry. - This quarry is located in T. 11 N. R., 10 E., within a quarter mile of that of the Chili Bar Slate Company, but on the north side of the river and west of the Placerville-Kelsey road. The principal opening was located about 600 feet north of the river, at an elevation of 150 feet above its bank. A tramway led down to the dressing yards, which were situated at the river bank.

    "The cleavage of the slates in the large opening strikes about N. 30 W., and has an almost vertical dip. No slate has been quarried here since 1897. A large stock of trimmed slates is still piled in the dressing yard, and many of these have already discolored badly.

    "Transportation and market. - The Eldorado County slates have practically no competition on or near the Pacific coast, while the Eureka quarry has recently placed large shipments in Hawaii and Guam. Until recently the principal problem has been the transportation of the slates from the quarry to the railroad. This was formerly done by wagon hauling over a 6-mile stretch of very hilly road. During the last season, however, the Eureka Slate Company has installed an aerial tramway system from its quarry to a point near Placerville. This tramway is an engineering feat of no mean order, the crossing of the South Fork of American River being the principal difficulty encountered."

    • Chili Bar (opposite), El Dorado County, California – San Francisco Slate Co.'s Quarry (Excerpts from Slate in the United States, Bulletin 586, by T. Nelson Dale and Others, United States Geological Survey, Washington: Government Printing Office, 1914.)

      "San Francisco Slate Co.'s quarry. - This quarry is located in T. 11 N., R. 10 E., within a quarter of a mile of that of the Chili Bar Slate Co., but on the north side of the river and west of the Placerville-Kelsey road. The principal opening was located about 600 feet north of the river, at an elevation of 150 feet above its bank. A tramway led down to the dressing yard, which was situated at the river bank.

      "The cleavage of the slates in the large opening strikes about N. 30 W. and has an almost vertical dip. No slate has been quarried here since 1897. A large stock of trimmed slates is still piled in the dressing yard, and many of these have already discolored badly.

      "Transportation and market. - The slates of Eldorado County have practically no competition on or near the Pacific coast, and the Eureka quarry has recently (circa 1906) placed large shipments in Hawaii and Guam. Until recently the principal problem has been the transportation of the slates from the quarry to the railroad.* This was formerly done by wagon hauling over a 6-mile stretch of very hilly road. In 1905, however, the Eureka Slate Co. installed an aerial tramway system from its quarry to a point near Placerville. This tramway is an engineering feat of no mean order, the crossing of the South Fork of American River being the principal difficulty encountered."

      (* As this 1914 report is essentially the same as the 1906 report in "Slate Deposits and Slate Industry of the United States, Bulletin No. 275," "Slate Deposits and Industry of the United States - California, by Edwin C. Eckel, pp. 56-59, Department of the Interior, United States Geological Survey, Washington: Government Printing Office, 1906.,"the shipments to Hawaii and Guam and the problem with the transportation by wagon occurred circa 1906 rather than nearer the published date of this report in 1914.)

  • Chili Bar (opposite), El Dorado County, California - the San Francisco Slate Company (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)

    This company operated the slate mines, and during the 1890s the slate was used as roofing slate quarried from several slate mines in this area. The slate mine/quarry area was located "on the north side of the South Fork of the American River, opposite Chili Bar."

  • Clarksville (southeast of), El Dorado County, California – Marble Valley Limestone (formerly the Schwalin Marble Quarry (Limestone/Marble & Lime Kiln) (Excerpts from "Limestone in California," by Clarence A. Logan, California Journal of Mines and Geology, Vol. 43, No. 3, July 1947, California Division of Mines, San Francisco, California, pp. 175-357. Used with permission, California Department of Conservation, California Geological Survey.)

    "Marble Valley Limestone (Henry Cowell Lime & Cement Company, 2 Market Street, San Francisco). Formerly these deposits were called the Schwalin marble quarry (in S ½ sec. 8, T. 9 N., R. 9 E.,) and Marble Valley quarry (in N ½ sec. 17, T. 9 N., R. 9 E.). Over 2500 acres of land surrounding these workings is assessed to the company.

    "Blue-gray to white limestone (marble) outcrops at intervals for over 2700 feet from the Schwalin pit southward to the south end of the Marble Valley quarry. At the north end the deposit is in and alongside of Marble Creek and the outcrop has been eroded down to the level of the surrounding land. The old pit from which stone was taken is 145 feet wide and not over 10 feet deep, as there was no provision for drainage. Though called a marble quarry, there is no evidence of any blocks of stone having been removed, and superficially it does not look as if such blocks could be had. The limestone was evidently burned in an old-style kiln nearby.

    "At the south end (sec. 17) there is an open quarry 180 feet wide by 300 feet long which has been worked to a depth of 20 to 25 feet. This is about the limit for which natural drainage is available. The north face is 120 feet wide, and shows good limestone; the west wall is not yet exposed.

    "The following is the analysis of a sample obtained by mixing samples cut across the width of deposit in both quarries mentioned above. Analysis was made by Abbot A. Hanks, Inc.

      Insoluble, 0.43 percent
      Ferric oxide and aluminic oxide, 0.42 percent
      Calcium carbonate, 98.80 percent
      Magnesium carbonate, 0.30 percent
      Total, 99.95 percent

    • Clarksville (southeast of), El Dorado County, California - Marble Valley (Schwalin) Deposit (Limestone & Kiln) (From "Mines and Mineral Resources of El Dorado County, California," California Journal of Mines and Geology, Vol. 52, No. 4, October 1956, California Division of Mines. Used with permission, California Department of Conservation, California Geological Survey.)

      "Marble Valley (Schwalin) Deposit. Location: secs. 8 and 17, T. 9 N., R. 9 E., M. D., 2 miles southeast of Clarksville in Marble Valley. Ownership: Henry Cowell Lime and Cement Company, 2 Market Street, San Francisco, California.

      "Years ago, limestone was quarried at this deposit and burned in a vertical kiln a quarter of a mile to the west. The last period of operation was about 1918 (Henry Cowell Lime and Cement Company, personal communication, 1955).

      "Limestone crops out at intervals for a distance of nearly 4,000 feet, but the total extent of the deposit is unknown. The deposit ranges from less than 100 to 200 feet in width. It apparently is lensoid and has a north-northwest strike. The limestone is medium grained and ranges from white to light bluish-gray in color...."

      "The deposit is developed by two open quarries. The north quarry is about 150 feet wide and several hundred feet long with quarry faces up to 40 feet high. The south quarry is 180 feet wide, 300 feet long, and 20 to 25 feet deep."

  • Clarksville (two miles southeast of), El Dorado County, California - Marble Valley (Schwalin) Deposit (Limestone & Kiln) (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)

    The Marble Valley (Schwalin) Deposit (limestone) was located two miles southeast of Clarksville. A nearby vertical kiln burned the limestone for the cement industry. El Dorado Limestone Company, and later the Gallo Glass Company, ran the mine. According to Mr. Noble's article, "The total extent of the deposit is unknown but the limestone outcrops for a distance of nearly 4000 feet, with a width from less than 100 feet to 200 feet. It was developed by two open quarries, one of which has filled with water. The mine is closed and the land is being converted to subdivision with custom home lots."

  • Clarksville (southeast of), El Dorado County, California – Schwalin Marble Quarry.

    Schwalin Marble Quarry - See: Clarksville (southeast of), El Dorado County, California – Marble Valley Limestone (Henry Cowell Lime & Cement Company) above.

  • Clipper Gap (south of), Placer County, California – De Witt Limestone Deposit (Limestone & Kiln) (Excerpts from "Limestone in California," by Clarence A. Logan, California Journal of Mines and Geology, Vol. 43, No. 3, July 1947, California Division of Mines, San Francisco, California, pp. 175-357. Used with permission, California Department of Conservation, California Geological Survey.)

    "De Witt Limestone. Assessed to Mrs. Eleanor De Witt, 1931 C Street, Sacramento, this small deposit in sec. 30, T. 13 N., R. 9 E., M.D., is about 1 ½ miles south of Clipper Gap, a station on the Southern Pacific Railroad. Possibly a quarter of a mile of new road would be needed for hauling.

    "Limestone outcrops for a length of 250 feet and has a width varying from 50 to 100 feet. It is a dark gray, compact stone possibly similar in chemical analysis to that at the nearby 'Lime Rock' deposit of Pacific Portland Cement Company. A small tonnage of limestone was quarried and burned here in an old stone kiln now in ruins. There are sufficient backs to permit mining a small tonnage in an open quarry as the limestone is on a slope."

    Analysis of limestone from DeWitt deposit, by Abbot A. Hanks, Inc.

    Insoluble, 2.79 percent
    Ferric and aluminic oxides, 0.60 percent
    Calcium carbonate, 94.80 percent
    Magnesium carbonate, 1.69 percent

  • Cool (near), California - Active Limestone Quarry

  • Cool-Cave Valley (one mile west of), El Dorado County, California - the West Cool-Cave Valley Mine (Limestone) (From "Mines of El Dorado County," by Doug Noble, El Dorado County Library web site. You can view this document in PDF format on the El Dorado County Library web site, or you can download the PDF document to your computer. See the “El Dorado County History” section for instructions to download the document.)
  • "The West Cool-Cave Valley Mine was a limestone mine one mile west of Cool-Cave Valley, near the Middle Fork of the American River. The deposit consisted of a lens 450 feet long and 50 feet wide, of bluish-gray, high-calcium limestone. Mining was by open pit."

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