“Mining, Processing and Beneficiating Carbonate Rocks in California,” by Oliver E. Bowen, James R. Evans, and Clifton H. Gray, Jr. (Chapter 3, pp. 29-33)
"Unlike the middle west or southwest parts of the United States, California has few flat or nearly flat-lying limestone-bearing formations. More often than not, California limestone bodies are thick, rather structureless masses, unmarked by distinctive horizons and somewhat variable in Chemistry. Commonly, such bodies are mined en masse, and the problems of chemical variation are ovecome (sic) by blending the various grades of rock. Igneous intrusions and interbeds of rock of non-carbonate character often necessitate considerable selectivity during quarrying. Land-surface relief is often considerable and in some cases extreme. Consequently, one cannot mine a few select beds of rock over large acreages. Five deposits currently are mined underground (circa 1973) - one to an inclined depth of 1300 feet. One major cement plant is supplied almost wholly by underground mining.
Acquisition of Mineral Properties
"Many deposits of carbonate rock are privately owned, title to these deposits having passed from public to private ownership under various land and mining laws...."
"Most California limestone and dolomite deposits are situated on hills where they can be readily quarried from level benches cut into the hillsides. In some places, however, it has been necessary to utilize pits sunk well below local base level, with resultant higher quarry costs. There are four large, and one small, underground mines from which limestone, dolomite, or both are obtained (circa 1973). At Davenport, Santa Cruz County, there is one large glory hole operation where the haulageways and part of the rock-storage facilities are underground. Underground mines are found at: the Crestmore cement operation of American Cement Corporation, Riverside County; U.S. Lime Products Division of The Flintkote Company, Sonora, Tuolumne County; the El Dorado Limestone Company, Shingle Springs, El Dorado County; the Diamond Springs Lime Company near Auburn, El Dorado county; and the dolomite operation of Premier Marble Products near Keeler, Inyo County. Other underground mines have operated intermittently at Felton, Santa Cruz County, and near Keeler, southeast of Premier's operation. Diamond Springs Lime Company's mine was originally a glory hole operation under a previous operator.
"With a few exceptions, California limestone and dolomite deposits are so tenacious that blasting is required to break the rock into fragments of suitable size for handling and processing. Two notable exceptions are the Skyline limestone deposit near Crystal Springs Lakes in San Mateo County (currently inactive) (circa 1973) and the Westvaco dolomite deposit near Hollister in San Benito County. At both of these deposits, the rock has been shattered by faulting in the San Andreas fault zone, so that little or no blasting is required to break the rock.
"The cost of underground mining of limestone generally is upwards from 75 cents per ton of rock delivered to the mill.
"In common bench-quarrying practice in California, 20-, 30-, and 50-foot or even larger bench spacings (vertical distance between floor levels or height of the working face) are adopted, depending upon the topography, distribution of various grades of rock in the deposit, safety factors, and other considerations. A line of holes commonly is drilled at a suitable distance back of the working face, from the top of the face down to the approximate level of the quarry floor. The spacing of these holes and the distance from the working face is dependent upon the type of explosive being used, the breaking strength of the rock the degree of fragmentation desired, and other related factors. The diameter of the holes ranges from three inches to more than nine. Explosives manufacturers are continually improving explosives and blasting practice, which are adaptable to the needs of producers of carbonate rocks. Development and use of drill rigs capable of making large inclined blast holes in a renewed application of principles known since 1918. Some companies are contracting most of their blasting operations to explosives companies. Costs of quarrying limestone range from 40 to 80 cents per ton in very large operations to one or two dollars or more in small ones for each ton of rock delivered to the mill.
"At many California operations near population centers or transportation lines, it is desirable to blast as infrequently as possible. In such cases, very large masses are broken in a single blast. It is not uncommon to break a million tons or more of rock at a time. Secondary blasting is often avoided by use of large drop balls weighing from 1,000 pounds to several tons attached by cable and boom to an electric, diesel, or gasoline powered winch. The ball is dropped onto such pieces of broken rock as are too large for easy handling.
"Room and pillar, shrinkage stope, top slicing and block caving methods have been successfully employed in California limestone and dolomite mines. U.S. Lime Products Division of The Flintkote Company at Sonora, Tuolumne County, employs a modified room and pillar method, workings being driven from a vertical shaft, down over 500 feet. The rooms commonly are 50 feet wide and several hundred feet long. Some reach a height of 50 feet. The deposit is a nearly vertical tabular mass of carbonate rock 300 feet wide and more than 1,000 feet.
"The El Dorado Limestone Company mine near Shingle Springs, El Dorado County, employs the shrinkage stoping method. Limestone occurs in two nearly vertical (80° to vertical), tabular to slightly lenticular, subparallel masses ranging from a few feet to nearly 50 feet apart. The east mass averages about 60 feet wide and the west 40 feet wide. Entry to the mine in the east mass is by a three-compartment 80° inclined shaft 1,200 feet deep. Early in 1964 stopes were being developed on the 1,160-foot level but most of the mining was on the 960-foot level. Completed shrinkage stopes have been developed in the thickest parts of the mass, the largest being 600 feet long, 70 feet wide, and 300 feet high; others are smaller. The haulageways to the shaft are 20 feet wide and eight feet high. Short crosscuts driven perpendicular to the main haulageways connect with draw points from the stopes. The limestone bodies have an economic limit in length of approximately 1,400 feet, almost all of this being south of the shaft.
"Prior to 1954, the Crestmore mine of Riverside Cement Company (now the Riverside Division of American Cement Corporation) (circa 1973) used the block caving method of mining. Entry was effected through a five-compartment vertical shaft 350 feet deep. The caved blocks were about 200 feet high, 200 feet wide and 240 feet long. Blocks were isolated by cutoff shrinkage stopes at both sides and ends. The haulage level consisted of parallel drifts driven on 70-foot centers and the mining level consisted of parallel drifts driven on 35-foot centers (Robotham, 1934, p. 1-20; Tucker and Sampson, 1945, p. 174; Wightman, 1945, p. 215-224). Access and ore-pass raises connected the mining and haulage levels. Two limestone masses have been worked in the underground mine. These are 200 to 300 feet thick and dip underground at angles of between 30° and 45°. The two ore bodies are separated by several hundred feet of granitic rock.
"Early in 1954, mining by block caving ceased and rock was supplied to the cement plant from surface quarries while a new mine was being developed. Placed in operation in 1956, the new mine will ultimately reach an inclined depth of 1500 feet. Mining is now done by the room and pillar method, rooms being 60 feet wide, 90 feet high and running the full width of the ore bodies, about 200 feet. For several years rock was removed from the mine over a spiral truck haulageway 30 feet wide with a vertical clearance of 20 feet and a grade of 10 percent (Persons, 1955, p. 76-77). The trucks were electrically driven and conventional electric shovels were used for loading. Most recently rock removal has been over belt conveyors.
"Room and pillar mines entered by sidehill adits have been operated for dolomite near Keeler, Inyo County, and for limestone near Felton, Santa Cruz County.
"Rock is transported from the quarry to the processing plant or to market by truck, rail, belt conveyor, pipeline (as slurry) and various combinations of these methods. Specially designed rear- and side-dumptrucks, trailers and railroad cars are being devised to facilitate transportation and reduce handling costs. The trend is toward larger capacity rigs except at the small operations. Loading is accomplished by electric shovels, gasoline-powered skip loaders, bucket and belt conveyors and even by simple bulldozer and ramp methods. Among new installations, the trend has been toward establishing primary and secondary crushing installations, chute-loading facilities and some sizing (screening) installations close to the quarries.
"California is a have-not state where limestone deposits near tidewater are concerned. In fact, few deposits of any consequence are very close to water-freight facilities anywhere on the Pacific Coast of the United States. Because of high truck and rail-freight haulage costs, tidewater limestone-consuming industries are taking a long look at water-freight possibilities. With large ships and automatic loading and unloading devices, limestone can be hauled for 1 or 2 mills per ton mile versus 2 or 3 cents per ton mile by rail or 4 to 7 cents per ton mile by truck. Under these conditions, certain Monterey County near-tidewater deposits may be brought into production, and Canadian and Mexican limestone may possibly become competitive with domestic sources at California ports. Canadian limestone already is in use in coastal and inland port areas of Oregon and Washington.
"For a great many purposes, limestone and dolomite processing simply involves crushing and sizing. Where certain trace impurities, such as iron oxide coatings, or small clay fractions are to be removed, a washing and scrubbing circuit must be added. In small operations, particularly those that may be temporary, it has become common practice to use portable combination units which consist of a jaw-crusher and screens or a jaw-crusher, hammer mill and screens together with recycling and loading belt or bucket-type conveyor-loaders. Several firms make units of this sort mounted on wheels. Permanent installations are, of course, more flexible and versatile in many respects.
"Where the end-product is to be finely ground, more elaborate equipment is necessary and much greater capital outlay is required. Various combinations of cone crushers, roll crushers, impactors (hammer mills), tube mills, rod mills and ball mills are used for secondary and fine grinding. Sizing may be accomplished by various combinations of rotating screens (trommels), vibrating screens, rake classifiers, hot dry-screening installations, air separators and the like (Perry, J. H., et al., 1950; Pit and Quarry Handbook, Taggart 1945)...."
History of Utilization of Carbonate Rocks in California (p. 45)
"The use of lime-bearing materials dates back to the building of the Spanish missions, where whitewash and lime mortars were used widely in small quantities. Abalone shells collected on the beaches probably were the first raw material burned into lime. Accumulations of fossils shells were found and used later, and finally the crystalline limestones were discovered and used locally. Not until the gold rush days of the middle 1850's did lime become important in the construction industry, but from then on, until the early 1900's, lime kilns sprang up all over California. The rise in demand for lime was directly related to the disastrous fires that repeatedly swept through towns composed of wooden frame buildings. Field stone or brick buildings laid up in lime mortar or mud and shuttered in steel became the standard type of construction throughout the gold country; many of these are still in use. A large quantity of lime was imported from Europe to supply the demand for masonry mortar during the gold rush.
"The lime-burning business probably had its heyday between 1880 and 1900 - in relation to its importance to the economy of that time if not in actual tonnage produced. Vast banks of lime kilns were constructed in the Santa Cruz Mountains, Santa Luca Range, Sierra Nevada foothills, Tehachapi Mountains, and southwestern San Bernardino County. Many of these lime companies were as significant for their day as the portland cement companies now are - in relation to the rest of the economy.
"Although portland cement was invented in England as early as 1825, it was not used to any great extent in California until the late 1850's and 1860's. The first cement used here was imported from Europe. Even then it did not greatly supplant lime mortars, nor did concrete become serious competition to masonry construction until about the turn of the century. Cement manufacturing in California dates back to 1860 when a hydraulic cement (a type manufactured at considerably lower temperature than portland cement) was placed on the San Francisco market. This was made at Benicia, Solano County, probably from scattered deposits of limy concretions, seashells and caliche plus clay. The first cement approaching the true portland type was made at Santa Cruz about 1877, from crystalline limestone and clay. Another early plant that produced a portland-type cement was built on the Jamul Ranch, San Diego County, in 1891. Since the early 1900's cement plants have been the largest consumers of limestone in California, but numerous other industrial uses of limestone are equally important to the economy of California even though the quantity of material they consume is smaller.
"Three other major limestone-consuming industries have figured prominently in the marketing of limestone in California for more than 75 years - sugar refining, steel manufacturing and glass manufacturing. Perhaps the steadiest consumer among these has been the beet sugar refining industry, which started in a small way as early as 1856, continued intermittently until 1889 and has been a steady consumer ever since. Present consumption exceeds 280,000 tons annually in California (circa 1973). However, inasmuch as the newer plants are being designed to recycle pond limes, future use of limestone in sugar beet processing is expected to decline. Steel making in California dates back to gold rush times and the advent of such foundries as the Joshua Hendy Iron Works. Limestone, however, was not used in any great quantity until the erection of the steel mills at Clipper Gap, Placer County, in 1880. Steel foundries and casting companies have been fairly large consumers of limestone and lime ever since. Erection of the Kaiser steel mill at Fontana, San Bernardino County, in 1942 resulted in a major increase in steel flux consumption in California. For a time, much of the fluxstone was imported from Nevada; but this has been greatly reduced. Current California consumption is on the order of 500,000 tons per year (circa 1973).
"Glass-making in California began in a small way as early as 1858 but was intermittent until about the turn of the century. Some early day factories used lime instead of the limestone now consumed. Notable periods of expansion have been the 1920's and the period since World War II. California's first plate glass plant was opened at Lathrop (near Stockton) by Libby-Owens-Ford in 1964. Plans for an additional plant at Fresno were progressing in 1966. Approximately 200,000 tons of limestone is consumed each year by California glass manufacturers.
"Dolomite was probably first used in California as a building stone. Dolomite dressed stone and field stone was used exclusively in the Sonora district of the Mother Lode in the 1850's and 1960's, and dolomite marble dimension stone was produced in Inyo County as early as 1888. Dolomite production was small and intermittent until 1942, basic flux for steel making being the principal product. In 1942, the Henry J. Kaiser interests initiated the use of dolomite as the principal raw material for use in magnesia refractories. During the decade following, other California producers of magnesia altered their process to utilize dolomite. The refractories industry now is by far the largest user of California dolomite. Prior to the advent of the use of dolomite, magnesia and other magnesium chemicals had been made from interaction of lime with sea water or from relatively small deposits of magnesite. Interaction of calcined dolomite with sea water results in a substantially larger yield of magnesia than lime plus sea water.
“Deposits Particularly Promising for Near-Future Development,” by Oliver E. Bowen and Cliffton H. Gray, Jr. (Chapter 5, pp. 46-50)
"Development and utilization of hitherto unused deposits of California limestone and dolomite on a major scale will depend primarily upon: (1) patterns of population growth; (2) advances in manufacturing technology; (3) construction of new transportation arteries (mainly highways); (4) placement of trunk utility lines, especially water, gas, and electric power; and (5) the degree of restriction that will be placed upon new and existing quarries and manufacturing plants through urban development. Expansion and centralization of populations inevitably result in intense competition for land among conflicting interests, particularly among the residential property interests, industrial property interests, fundamental raw material suppliers (i.e. rock, sand and gravel) and numerous recreational interests. Some counties and municipalities are pioneering in the field of land use planning with respect to utilization of mineral resources. Statewide studies of these problems are also underway.
"Carbonate rock deposits and districts believed to be of notable near-future economic importance are briefly summarized below. These will be described at greater length as the results of the other parts of a statewide investigation are published. The parenthetical notation at the end of each summary identifies the part of the investigation involved and the specific deposits described in some detail therein. No particular order of importance or specified time of probable development is implied in the following discussion.
(1) Coyote-Fish Creek Mountains
"Steady growth of the San Diego marketing area ultimately should be sufficient incentive for development of the extensive deposits of blue-gray crystalline limestone in the Coyote and Fish Creek Mountains of west central Imperial County, notably those in the vicinity of Carrizo Mountain. During 1966, Texas Industries acquired and explored a large deposit at Carrizo Mountain. Reserves run into the hundreds of millions of tons. No other deposits of large size and high quality that might serve the San Diego area exist within the boundaries of the United States nearer than the northern San Bernardino Mountains or the Santa Rosa-San Jacinto Mountains complex. Because of the very low-cost water freight, it is, of course, possible to import limestone or dolomite into the Port of San Diego from Mexico or Canada at prices competitive with domestic rock (circa 1973). Extensive deposits of Cretaceous limestone exist on the west coast of Baja California within 100 miles of San Diego. (Coyote Mountains, Jumbo, Mountain Spring and Waters; Transverse and Peninsular Ranges Province VII)
(2) Back Canyon
"A district containing notable reserves of apparently high-grade, coarsely crystalline white and blue gray limestone exists within 15 miles of the producing Tehachapi-Monolith district of Kern County at the headwaters of Back Canyon in the upper Caliente Creek drainage basin. These deposits are 12 to 18 miles from State Route 58 and the rail lines of the Tehachapi Pass and Owens Valley routes. Construction of one or more of the proposed new roads to serve this vicinity would put these deposits in a good competitive position; lack of good access roads has delayed their development (circa 1973). (Monarch Lime Company, Loraine, Ritter Ranch and Rudnick Estate; Province IV)
(3) San Bernardino Mountains
"Very large reserves of limestone and some dolomite are distributed through the northern San Bernardino Mountains centering in the Cushenbury Canyon vicinity. Some of these have already been placed in operation by Kaiser Cement and Gypsum Company, Chas. Pfizer & Co., and several smaller concerns. Presence of a rail line to Cushenbury Canyon has increased the desirability of these deposits, although some are situated high in the mountains and would have to be served by truck. Much of the rock in this district is white or nearly so and suitable for many specialty products as well as for cement and general chemical use. (Blackhawk Canyon, Carriere, Cushenbury Canyon, Grapevine Creek, Kaiser Cement and Gypsum Corporation, Chas. Pfizer & Co., Inc., Rattlesnake Gulch, Rose Mine area, Tip Top Mountain, Twin Row, Sentinel, Golden Eagle Placer, White Mountain, Hesperia, Bowen Ranch, Blackhawk Mountain, Terrace Springs, White Rock and Marmo-Diamante; Province VII)
(4) Keeler Area
"Very extensive reserves of white, high purity dolomite exist near the rail line in the Keeler-Lone Pine district of Inyo County in both the Hidden Valley Dolomite and Anvil Springs Formation of Ordovician to Silurian age. High-purity white and blue-gray limestone deposits are also present in the nearby Lee Flat and Darwin districts to the east and southeast of Keeler, mostly in the Mississippian Bullion Member of the Monte Cristo Limestone. Premier Resources, Inc. currently produces dolomite marble near Keeler. (Limestone deposits in the Lee Flat, Darwin and Talc Hills vicinities and Dolomite district east of Lone Pine; Province V)
(5) Marble Mountains
"A considerable variety of limestone and dolomite deposits exists in the Marble Mountains of eastern San Bernardino County within 15 miles of the railhead at Cadiz. The proposed realignment of Interstate Highway 40 and possibly the railroad as well would improve the desirability of these deposits. Substantial deposits also occur in the adjacent Bristol and Ship Mountains. The district is particularly well known for the highly colored limestones and coarser grained marbles that are in various combinations of blue, black, red, and orange. The most attractively colored limestones tend to occur in the Cambrian Cadiz Formation although some exist in other Cambrian formations as well. Extensive deposits of massive, blue-gray to nearly white limestone and dolomite are found in several unnamed metamorphosed formations of late Paleozoic age in the northwestern part of the Marble Mountains. These are suitable for cement and for general chemical use. (Chubbuck Reserve, Vaughan Marble, Marble Dolomite, Snowcap, Jack Frost, Chalmers Dolomite, Castle Dolomite, Twin Buttes, and Ship Mountains; Province VI)
(6) Lake Hemet Vicinity
"The Whitlock deposit, located a few miles southeast of Lake Hemet in the San Jacinto Mountains of western Riverside County, is one of the few remaining undeveloped deposits less than 100 airline miles from Los Angeles or San Diego (circa 1973) that appears to be large enough to support a modern cement plant. A limited water supply and difficulties of finding a suitable manufacturing plant site, because of urbanization or inadequate utilities, has delayed development. (Province VII)
(7) Cima Area
"The Striped Mountains vicinity of the Mescal Range in northeastern San Bernardino County lies within 12 miles of the Union Pacific siding at Cima and three miles east of Cima road. Immense reserves of both blue-gray and white limestone of apparently good grade are exposed over favorable quarry terrain. The Bullion Member of the Mississippian Monte Cristo Limestone, The Crystal Pass Limestone Member of the Devonian Sultan Limestone, and certain parts of the Cambrian to Devonian Goodsprings Dolomite are the most promising objectives. Large masses of fine-grained, nondecrepitating high calcium limestone are available that can be competitive with rock currently imported from Nevada (circa 1973). (Cima Limestone, Geer Dolomite, and Mescal Range-Clark Mountains-Ivanpah Mountains; Province VI)
(8) Maria Mountains
"White limestone and white dolomite of apparently high purity are found in the Little Maria and Big Maria Mountains of eastern Riverside County near Midland. Reserves are estimated to run into the hundreds of millions of tons. These carbonate rocks occur chiefly in the Maria Formation of probable Paleozoic age. Distance from markets and unfavorable rail freight rates have hindered development of these deposits although small tonnages of ornamental stone have been marketed. They are, however, within a few miles of paved roads and a branch rail line. (Blythe Cement Nos. 1-5, Bonnie Limestone, California Limestone Products, Driftstone Veneer Nos. 1-2 and Driftwood No. 2, Limestone Nos. 1-8, and Shane Nos. 1-2; Province VII)
(9) Frazier Park
"In the general vicinity of Frazier Park, southwestern Kern County, coarsely crystalline white to gray, massive limestone occurs in numerous pendants in Mesozoic granitic rocks. The area has numerous deposits suitable in quality for manufacture of portland cement and for general industrial chemical use. Some doubt exists whether the reserves are large enough to attract a large cement plant. The deposits are close to a paved road and are about six miles west of U.S. Highway 99 (Interstate Route 5). Although the deposits are situated between the Los Angeles and Bakersfield marketing areas, lack of rail facilities may prove a deterrent. Thus far (circa 1973), roofing rock has been obtained in this area. (Lebec, Tecuya, and White Ridge; Province VII)
(10) San Gorgonio Pass and Vicinity
"Several undeveloped deposits of moderate to possibly large size exist in the northern San Jacinto Mountains. These deposits contain considerable tonnages of high calcium-low iron limestone but also include intermixed dolomite and magnesian limestone. They are close to rail transportation and to Interstate 10, but their development has been hindered by problems of access across adjoining lands and opposition by residential property interests. Among the more accessible of these are the Guiberson and Sims deposits. (Others include the Blue Diamond, Chino Canyon, Eagle, Fingal, Mount Edna, Novelle, Potrero Creek, and Southern Pacific; Province VII)
(11) San Marcos Pass Vicinity
"Moderately extensive deposits of fine-grained, light-colored algal limestone occur in the Eocene Sierra Blanca Limestone in the Little Pine Mountain vicinity of Santa Barbara County. These lie within ten miles of good county roads (the San Marcos Pass route) and constitute one of the few sources of industrial limestone in this part of the state. Lack of good access roads, as well as limited market opportunities has delayed utilization of these deposits. Some are close to or within the proposed San Rafael Wilderness Area. (Sierra Blanca; Province III)
(1) Pico Blanco
"The only extensive high-grade limestone deposits on the Pacific Coast of the United States, exclusive of Alaska, within three miles of potential marine transportation are in Monterey County, 25 miles southeast of Monterey at Pico Blanco and vicinity. Reserves there are on the order of a billion tons. Most of the rock in these deposits is coarsely crystalline, snow white, and of high purity, which further enhances the desirability of the deposits for many industrial purposes. However, utilization of this extremely valuable group of deposits is already threatened by urbanization and conflict of interests (circa 1973). (Pico Blanco; Province III)
(2) Lake Shasta Area
"Various deposits in the vicinity of Lake Shasta, Shasta County, contain the only extensive reserves of fine-grained, nondecrepitating limestone available within reasonable distance of northern California markets. The only likely sources elsewhere would be from Mexican or Canadian deposits competitive because of the very low cost of water freight. The Hosselkus Limestone and Pit Formation of Triassic age contain the most uniform rock and the rock most likely to be low in magnesia. The more extensive McCloud Limestone of Permian age locally is good but has extensive replacement masses of dolomite more or less throughout. Limestone of the Devonian Kennett Formation is generally of good quality, but few of the deposits are large and most are relatively inaccessible. (Province II)
(3) Volcano Area
"Large uniform deposits of blue gray, crystalline limestone are present at Volcano, Amador County, within 12 miles of the railhead at Martells. These have been controlled for many years by the Riverside Cement Division of American Cement Corporation. They were being explored as sources of industrial limestone and for a future cement plant at Ione in 1966-67. They are particularly well situated to supply future Central Valley markets. (Volcano Limestone; Province IV)
(4) Murphys-Columbia-Sonora Area
"This district already supports several important producers of industrial limestone and dolomite, and other properties are already marked for near-future exploration (circa 1973). Reserves of both limestone and dolomite are very large. Centrally located within 125 miles of San Francisco, adjacent to the Central Valley, and well supplied with trunk utility and transportation lines - this district is attractive to new industry. Within the next few years, The Calaveras Cement Division of The Flintkote Company will activate its properties in Cataract Gulch to supply its already existing plant at San Andreas. (Childress Ranch, Columbia Ditch, Columbia Dolomite, Eastman Ranch, Hyde Ranch, Letora Ranch, Mayhall Ranch, Murphys, Musante Ranch, Port Stockton Cement, San Diego Reservoir, Skunk Gulch, Woodham Ranch deposits; Province IV)