- Deposit Type: Vein, Breccia and Stockwork
- Commodity: Silver
- State/Province: UT
- Country: United States
- Latitude: 39° 55' 56'' N
- Longitude: 112° 6' 43'' W
Main Tintic Mining District.
Mammoth Mine Surface 1910
Situated in Juab County, 70 miles SW from Salt Lake City, in the mining friendly State of Utah. The Main Tintic District ranks 4th in underground precious metals districts in the U.S. The Main Tintic underground mines are characterized as requiring minimal underground rock support, temperatures about 75 degrees, with a deep water table. 90% of production has come from large dimension replacement ore bodies in carbonate rocks, which are amenable to modern mechanized underground mining. Infrastructure including electrical and transportation are in place. Highway US-6 passes through. Union Pacific Railroad is adjacent on the west. DO NOT CONFUSE with the nearby East Tintic Mining District in Utah County—which has very different and much less favorable mining characteristics. Since 1900, When the U.S. Bureau of Mines began keeping records, the Main Tintic District has produced 13 million tons of ore, from which was recovered: 208 million ounces silver; 2.2 million ounces gold; 247 million pounds copper; and 1,318 million pounds lead. No production figures are available from 1872, when mining began, to 1900. Production had ended at all Tintic District metal mines prior to 1958 as a result of low metals prices, and antiquated mining methods—not for lack of ore. Little modern exploration has been carried out, and numerous high potential ore targets remain untested. Conflicting and fragmented property ownership has negatively hampered exploration and mine development. Property ownership of major mines has now been consolidated. The Main Tintic Mining District remains a “SLEEPING UNDERGROUND GIANT.”
Mammoth MineThe good news—PROFIT from reopening the Mammoth Mine. The Mammoth Mine was 3rd in total production in Main Tintic, and was highly profitable. Metals recovered from 1.3 million tons of Mammoth Mined ores, after 1900, were: 13 million ounces of silver; 368 thousand ounces gold; 37 million pounds copper; and 36 million pounds lead. No records are available from early high grade ores mined between 1872 and 1900. The Mammoth Mine has been previously owned by the McIntyre family. As a family owned mine, modern exploration has been very limited. The Mammoth Mine, throughout its history, has always contained significant unmined ore reserves. Company mine production ended in 1953, except for 45,481 tons of high silica flux ore mined between 1979 and 1982 by Kennecott (under lease agreement) from the lower levels, to feed the Garfield Smelter. Ore mined by Kennecott was lifted to the surface using one ton ore cars, up the antiquated shaft–one car at a time—just like ore was mined prior to 1900. The Mammoth shaft, (sunk during the 1870s) passes through a portion of the vertical ore body. This ore has been left unmined to this day, because of concern for damage to the upper portion of the shaft. This “shaft pillar” ore extends from near the surface to the 550 level, and contains 65,000 tons grading 22 opt. silver; 0.25 opt gold and 10% copper. Modern mining techniques can now safely “harvest” this excellent ore, without damage to the shaft. Historic ore reserves of 115,000 tons have been drilled out in the Mine’s lower levels. These reserves have an average grade of 15 opt. ton silver; 0.6 opt. gold, and 5% copper. Numerous high value exploration targets remain untested in various parts of the mine. Rich oxidized zones of high grade silver ores (mainly cerargyrite) have been mined at various levels. One of the richest was the North Extension Fissure (between the 1200 and 1500 levels) which had assays in the range of 300 opt silver.
Mine Workings and Surface PlantTwo shafts: the Main Mammoth and the Lower Mammoth access the deep underground workings, and two horizontal tunnels (the Haulage and Plummer tunnels) access the upper workings from the surface. The Mammoth Shaft is 2600 ft. deep (below the 1872 shaft collar) and the Lower Mammoth Shaft is 2000 feet deep, with the collar 600 ft. lower than the Mammoth shaft collar. The shafts are connected at the Lower Mammoth 1600 ft. level. An underground hoist is installed in the Haulage Tunnel at the 300 level on the Mammoth Shaft. The mine has an outside water system supplied by pipeline and pumping stations from an owned well in the nearby Tintic Valley. Electrical service consisting of 440 Volt 3 Phase is installed at the mine site. Access is by blacktop county road 2 miles from U.S. Highway 6.
Hydro-Metallurgical Ore ProcessingPast production from the Mammoth Mine has been mainly oxidized ores, which are suitable for hydro-metallurgical processing on site. This method of processing will produce marketable silver, gold, copper, and zinc, without the need for an intermediate smelting step, and will eliminate the need for transporting the ore elsewhere for metals recovery. It is expected that an initial ''scalping'' concentration step will remove lead plus any sulfide minerals for conventional smelters. The design of an ''ore dressing'' process plant will be required.
Bulk Sampling feasibility studies show that the ore from the Mammoth Mine is amenable to column/Vat leaching. Samples of ore from the upper levels of the Mammoth Mine were tested for metals recovery using cyanide. Ores above the 2400 level are nearly totally oxidized and ores between the 2400 and 2600 levels are mixed sulfide and oxide. Bottle tests were carried out on typical ore samples. Results of these tests confirm that hydro-metallurgical processing methods are applicable to Mammoth Mine Ores.
Old Bonanza Mines Can Be Made New Again----The attached photograph of the MAMMOTH MINE shows the massive size of the mine facilities. This mine employed hundreds of men a century ago. The Mammoth Mine provided employment and income to support the town of Mammoth (population~2,500). The ore bodies were never mined out—the mine can be “made new again.”
----The Tintic Mining District consists of an incredible concentration of gold-silver-copper and other metals. Tintic is like a “birds nest on the ground” awaiting those enterprising enough to gather up the pretty gold and silver eggs. Mammoth Mines, Inc. land position consists of patented mining claims which are “fee simple” ownership.
----Changes in exploration and mining technology, since the days of historic production, are enormous. Exploration by driving a tunnel or sinking an exploration shaft into the mountainside (guess and hope) has been replaced by a host of powerful new geological, geophysical and computer modeling tools for the discovery of new ore.
----The Mammoth Mine Center has hundreds of historic technical and financial items, including maps, geologic reports, production records and other data that will significantly assist in the modern exploration and development of the Mammoth and adjacent mines, that were historically so productive.
--- The Tintic Mining District is one of those rare places on the earth’s crust where gold-silver and other metals occur in high grade commercial concentrations. Historically, underground, “stringers” of mineralization were followed hoping to find ore zones. Where the “old timers” failed, the “new timers” will succeed.
----The ore grades at Mammoth are high. Underground mining will enable the production of high grade precious metals ores that can be direct smelted or processed on site using hydro-metallurgy. The days of pick and shovel mining, with mules pulling the ore cars, has at last come to an end.
WebsitesMammothmine.com, Geminimines.com, and Knightsilvermines.com
ReferencesBush, J.B. 1957 Introduction to the Geology and ore deposits of the East Tintic Mountains and Ore Deposits of the Tintic Mining Districts: Utah Geol. Soc. Guidebook to the Geology of Utah, no. 12 p. 97-102
Cook, D. R. 1957 Guidebook to the Geology of Utah number 12, ''Geology of the East Tintic Mountains and the Ore Deposits of the Tintic Mining District'', Utah Geological Society. SLC.
Crane, G.W., 1917, Geology of the Ore Deposits of the Tintic Mining District: A.I.M.E. Trans., v.4 pp. 342-356
Evans, M. T., 1957, Ore deposits of the Chief mine in Geology of the East Tintic Mountains and ore deposits of the Tintic mining Districts: Guidebook to the Geology of Utah, No 12. pp. 80-93
Kildale, M.B., 1938, Structure and ore deposits of the TIntic District, Utah: Stanford University, Stanford, Calif., Ph.D. Dissertation
Lindgren, W. and G.F. Loughlin with historical review by V. C. Heikes. 1919 United States Geological Survey Professional paper 107 ''Geology and Ore Deposits of the Tintic Mining District'' Washington Government Printing office.
Morris, H.T., 1968, Graton-Sales Volume, AIME, p.1043-1074. The Main Tintic mining district, Utah: in Ridge, J.D., ed. Ore deposits of the United States, 1933-1967,
Morris, H.T., 1964a, Geology of the Eureka quadrangle, Utah and Juab Co.s, Utah: U.S.G.S. Bull. 1142-k, p.29
Tower, G.W., Jr., and Smith. G.O., 1898, Geology and mining industry of the Tintic District, Utah: U.S. Geol. Survey 19th Ann. Rpt. (1897-1898). Pt. 3. p. 601-767