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By Anthony J. Chasteen

Although geothermal energy has been used by mankind for thousands of years and has even been used to generate electricity since the turn of the century, it is only in the last few years that the threatened energy crisis has focused attention on this resource. Geothermal exploration and development is being carried out in at least thirty-five countries on five continents. The status of geothermal energy production, however, is rudimentary with about 800 MW installed generating capacity worldwide, equal to about 0.1% of the world's total energy production.' The world's first (1904) commercial generating site at Lardarello, Italy, will soon be surpassed by developments at The Geysers, Calif. There are other successfully operating geothermal power projects in New Zealand, Japan, USSR, Mexico and Iceland with pilot plants planned or under construction in Chile, El Salvador, Nicaragua, Turkey and the Philippines. The preponderance of exploration and development is being sponsored or assisted by individual governments, by the UN or by the U.S. Agency for International Development

Jan 10, 1972

By S. F. Willey

Difficulties encountered in justifying replacements for overage mobile mine equipment at the Gay mine are common to most mining operations. More critical management reviews, resulting from ever rising capital expenses, increased such difficulties. These increased difficulties are especially apparent to those who are primarily operators and are not statisticians, mathematicians or computer men. The Gay mine is located 17 mi east of the town of Fort Hall in southern Idaho. This open pit operation annually supplies the J. R. Simplot Co. and the FMC Corp. with 1.5-2.0 million tons of phosphate ore. Stripping ratios average approximately three bank cubic yards of waste per ton of ore mined. The mobile mine equipment fleet consists of ten 24-cu yd scrapers; twenty-one 30-50-ton end-dump trucks; four 3%-4%- cu yd shovels; fifteen dozers in the D-8 and D-9 classes; and three road patrols. Equipment replacement is based on the results of evaluations made on individual units.

Jan 9, 1972

By Jerry M. Thornton, Richard W. Cannon, Don C. Rotherham

The orebodies of Gibraltar Mines Ltd. (N.P.L.) are located on the western slope of Granite Mountain, central British Columbia. The area in and around Gibraltar Mines has a moderate topographic relief with elevations between 3500 and 4100 ft. The property is 95% covered by overburden which varies in depth from a few feet to 230 ft. Early History and Geology The present Gibraltar Mines property before amalgamation consisted of the Pollyanna property (Duval-Canex) and the Gibraltar property (original Gibraltar Mines) as well as some Coast Silver and McLeese Lake Copper claims.

Jan 9, 1972

By Calvin C. Brown, John Bigando

Pit slopes at Cananea commonly vary from 50-55°, and some have been standing for over 25 years. Their maximum vertical extent is 700 ft. Investigation of these slopes and the rocks of which they are composed has led to the decision to experiment with final pit slope angles of up to 70". Precision blasting to obtain a smooth final pit wall with minimum raveling is an integral part of this field experiment. Presplitting, one of the precision blasting techniques, requires the drilling of a single row of holes along the limit of a pre- designed excavation. The hole spacings and charge concentrations must be experimentally determined in the field, using published data as a base (Table 1). The holes are fired prior to the main round and carry no burden and therefore produce no broken rock. Thus, it is an operational cost with no direct return on investment.

Jan 9, 1972

By J. C. Irvine

Meramec Mining Co., a joint venture by Bethlehem Steel Corp. and St. Joe Minerals Corp., is engaged in the mining, concentrating, and pelletizing of iron ore from the Pea Ridge mine near Sullivan, Mo., about 70 mi southwest of St. Louis. The orebody lies under about 1300 ft of sediments. It is tabular, about 2600 ft long and up to 600 ft thick, and lies in an approximate east-west delineation. The orebody dips about 80"s and is of unknown depth. The ore is primarily high grade magnetite with smaller zones of specular hematite. The Precambrian wall rock is rhyolite porphyry. The mine is serviced through two concrete-lined shafts, 19 ft 1 in. diam and 2500 ft deep. No. 1 shaft, equipped with an "A" type head-frame and conventional cylindrical drums, hoists men, materials, and waste rock; it is also the downcast air shaft. No. 2 shaft utilizes tower-mounted friction hoists to handle the two production skips, each with 24-ton counterweights, and a small man cage. The mine exhaust passes through this shaft. Ore is principally mined by sublevel stoping,

Jan 9, 1972

By William J. Robinson

What is the cummulative rate of recovery of copper from a sulfide leach dump? The technical answers to this frequently asked question may vary from "I don't know" to "quite good" from people of the same company. Management also poses this question because it plays a vital role in planning future production. The answer is difficult because of the many variables between different operations such as physical construction of the dump, topography of the original site, characteristics of dump material, mineralization and water application. Each of these factors and others have a bearing on the rate of recovery. Anaconda's method of water distribution at Butte is unique in that each dump is drilled to allow physical injection of water into the dump. The injection holes are drilled vertically on 25 ft centers from the surface of the dump. Normally, the holes are drilled 40 ft deep and cased with 4-in. PVC perforated pipe. The pipe is perforated at one-foot intervals with four 1/2 in. diam holes at 90" spacing on the pipe circumference.

Jan 9, 1972

By E. E. Malouf

For centuries small amounts of copper have been recovered from acid mine-drainage waters. In recent years, the expansion of copper-bearing waste dump leaching for copper recovery has established a technological basis that is rapidly converting the art of copper leaching into a science. Copper leaching and recovery from solution has become an important adjunct of nearly all copper mining operations. Leaching of copper, whether from copper- bearing ore or waste, follows well established chemical reactions commonly in an acid circuit, but where leaching of copper is to be made in rock that is a high acid consumer, ammonia and ammonia carbonate, as well as cyanide leach solutions, can be used effectively. Current hydrometallurgical processes are being applied at an ever increasing rate to recover the trace amounts of copper in copper mine waste by in-place leaching. Currently approximately 300,000 tons of copper are produced annually in this manner while as recently as ten years ago, only one-eighth of this amount of precipitate copper was produced. Where copper occurs as an oxide in higher concentrations as to be classified as an ore rather than waste, then the hydrometallurgical processes are applied as percolation or agitation leaching in vats, pachuca tanks or prepared heaps. This approach gives better control over the recovery of the leach solutions, particularly in the processes where ammonia or cyanide leaching agents are to be used.

Jan 8, 1972

By D. J. Christie, W. C. Hellyer

Three autogenous grinding flowsheets were considered as follows: 1) Primary autogenous grinding of a -8-in, primary crusher discharge to produce a product suitable for second stage pebble milling, or a flotation feed product in a single stage of grinding. 2) Intermediate autogenous grinding in which +4-in. rock media is screened from the primary crusher discharge and employed as grinding media to grind a tertiary crusher product to flotation feed size in a single stage.

Jan 8, 1972

Conquista, the uranium mining and milling complex owned jointly by Continental Oil Co. and Pioneer Nuclear, Inc., has begun operations in Falls City, Texas. The mill has been designed to produce 1.5 million lb of U3O, from 600,000 tpy of ore mined. Currently, the plant processes a maximum 2000 tpd of ore. Mine Planning Texas ore deposits are small and scattered in comparison to other uranium mining districts. Those to be mined at Conquista range from a few acres to more than 100 acres in size. Ore thickness ranges from a few inches to over 15 ft, and depth from less than 20 ft to more than 170 ft below ground surface. Distance from the mill ranges up to 35 mi.

Jan 8, 1972

By George L. Atwood, William Brown

Phosphate ore is being mined at Monsanto Co.'s Henry mine, near Soda Springs, Idaho, for the company's three furnace elemental phosphorus plant near Soda Springs. The finished product from the furnaces is elemental phosphorus which is subsequently used in the manufacture of detergents, food preservatives, fire retardants and other consumer items. In stripping and mining, D-9 crawler tractors are utilized to rip and push-load rubber-tired scrapers. The equipment consists of six D-9G crawler tractors, four Caterpillar 657B scrapers, eight Euclid S-24 scrapers, one Reich T750 drill and one Caterpillar No. 16 patrol plus various support equipment. Stripping is performed on a 12- month basis, two shifts per day, whereas mining is mainly in the summer months on a one-shift basis. The hauling season begins May 15 and ends November 1 due to freezing weather and snow conditions. Annual production is 1 million tons of phosphate rock and 2.5-3 million cu yd of stripping. Stripping, mining and hauling is performed for Monsanto by Dravo-Soda Springs, a mining contractor which owns, operates and maintains all equipment used. The contractor is paid for stripping by the bank yard and for ore mined and hauled on a tonnage basis.

Jan 8, 1972

By John W. Tieman

Research on processes to remove sulfur oxides from flue gas has been in progress for many years. Pioneers in this field were the British who, in the early 1930's, installed a full-scale flue gas scrubbing unit on a 120 MW boiler using alkaline water from a Thames estuary plus chalk. Since that time, various methods have been studied by many investigators. Federal laws covering air pollution started with the 1955 Air Pollution Control Act. With the advent of the Air Quality Act of 1967, and subsequent publishing of criteria and available technology for control of sulfur oxides in January 1969, the clamor for information on commercially available control techniques to remove sulfur from fossil fuels has rapidly increased.

Jan 8, 1972

By Ferron A. Olson

Occasionally it is good to consider the past, assess the present and project the future. Curriculum, enrollment, matriculation of graduates and changes in industry which influence mineral education are all relevant for determining what changes will be needed in educational institutions to support growth and development in the United States. It would appear likely that with environmental pressures, energy needs with present stress in fossil fuels and general societal needs for metals and minerals that mining and metallurgical engineering faces a period of growth and may be on the threshold of a new era with a vitality that has not been enjoyed for several decades. The following information is based on material obtained through questionnaires received from twelve schools accredited in mining or mineral engineering (out of 18 in the U.S.), 2 not accredited and 5 which no longer have mineral engineering disciplines. The schools presented do not include the smaller nor larges of the undergraduate programs in mining engineering.

Jan 8, 1972

By Martin J. Gungl, J. Lyman MacInnis

None of the industry submissions could persuade the Canadian Tax Reform draftsmen that the rate of return has had as much bearing on investors' decisions to invest in Canada as the success records of Canadian ore findings. The goverment opted for the position that mining capital goes where the ore can be found. Many tax incentives which were available until the end of 1971 have been greatly reduced. However, it is still recognized that new ventures in exploration and development of natural resources deserve a break even if there is reduced recognition of the established and highly successful members of the industry unless they continue to search and develop. The latter will also get some breaks for processing beyond the prime metal stage.

Jan 7, 1972

By Alfred Weiss

Approximately 850 delegates from 24 countries met in Tokyo, Japan, May 24-27, for the second MMIJ-AIME Joint Meeting in 55 years, to exchange technical knowledge and experience in the fields of exploration, mining, metallurgy and petroleum engineering. The first such meeting was held in 1917 in Kyoto, Japan. Although the Mining and Metallurgical Institute of Japan was the sponsor, the entire meeting (machinery exposition, technical program, and tours) was a joint effort of the two institutes.

Jan 7, 1972

By Henry Carlisle

Henry Carlisle: This is November, 1960, and my good friend John Gustafson is sitting on the other side of a tape recorder. I, Henry Carlisle, am going to ask him some questions on the highlights of his life, and he has been good enough to say that he will play this question and answer game with me. Now, John, let's pick out a very interesting period when you went to North Labrador and made a preliminary investigation of the big iron deposits there. You were working for either Timmins or Hollinger, which was it? John K. Gustafson: I was in charge at that time of a Hollinger Exploration Co. office in Toronto. We had acquired options on enough shares to control Labrador Mining and Explorations Co., and through Hollinger North Shore Ltd., another company, we had a 3000 square mile concession in Ungava, Quebec, on the direct extension of the iron ore fields.

Jan 7, 1972

SME Membership Directory Listings of record March 31, 1072 SOCIETY OF MINING ENGINEERS OF AIME

Jan 7, 1972

By William G. Schultz

Sylvite’s potash mine probably ranks as one of the most highly mechanized and automated mining operations in the world. Employing, on a normal 10-hr production shift, one supervisor and a crew of seven operators, Sylvite is able to mine at an average rate in excess of 600 tph. The ore is produced by two Marietta miners weighing 258 tons, making them the largest and heaviest piece of equipment ever taken underground. The ore produced by these two Marietta miners is conveyed to the shaft area, cycled through a 15,000 ton storage system and hoisted to surface completely automatically. The operation of all equipment in the mine can be monitored and controlled from a central control panel located underground.

Jan 7, 1972

Canada's newest low-grade porphyry copper mine, Gibralter Mines Ltd. (N.P.L.), has reached production. The subsidiary of Placer Development Ltd., located at Williams Lake in the Caraboo District of central British Columbia, began open pit mining in mid-June on reserves estimated at 358 million tons assaying 0.373r: Cu and 0.016C; MoS,. Each of four separate zones will be mined in a predetermined sequence, in one or more stages, and with a throughput of more than 36,000 tpd. The sequence and stages of mining the zones have been determined by computer calculation and economic analysis and are designed to maximize recovery and minimize cost. At the very least, the mine is off to a promising start. Development costs leveled off at $67 million. 9'; below the anticipated budget.

Jan 7, 1972

By Kent W. Pilz

Wet dust suppression can be achieved by 1) confinement of the dust within the dust producing area with a curtain of moisture, 2) wetting of the dust by direct contact between the particles and droplets of moisture or 3) the formation of agglomerates too heavy to remain airborne, or too heavy to become airborne, by combining small dust particles with each other and with the droplets of liquid. From the standpoint of economy, availability and safety, water is the ideal fluid; however, it is not as effective for dust suppression as when small percentages of specially formulated dust control compounds are blended with it. Performance of dust control com pounds is related to surface active agents and surface activity. In all liquids there is an attractive force between molecules which varies inversely as the sixth power of the distance between molecules. Thus, in the liquid phase where molecules are crowded together, the intermolecular forces are powerful; whereas in the liquid-vapor phase where the molecules are relatively far apart, these forces diminish rapidly. In the body of a fluid there is an uneven distribution of forces resulting in an inward pull called surface tension. The force which keeps two surfaces apart or causes them to coalesce is termed interfacial tension. Fluids of high surface tension exhibit poor wetting, spreading and penetrating qualities. Water has the unusually high surface tension of 72.75 dynes per cm at 20°C.

Jan 7, 1972

By F. P. Haver, M. M. Wong

When a mixture of chalcopyrite concentrate and lime is heated in air, the following reaction takes place: 2CuFeS2 + 4Ca (OH)2 + 8 ½ 02 ; 2Cu0 + Fe203 + 4CaS04 + 4H20. Ca (OH)2 is the only common reagent that will adequately control SO2 evolution in roasting. Other additives tried, including CaO, CaCO3, Na2CO3, NaOH, MgO, Mg (OH)2, and MgCO3, were not effective. All reacted with sulfur, but not to the extent that will be required to meet the new control regulations for sulfur oxide emissions. For example: when the concentrate was heated with the theoretical amount of limestone (CaCO3), about 55% of the sulfur was retained in the calcine; whereas use of the stoichiometric amount of Ca (OH), converted approximately 99% of the sulfur to CaSO1. In most of the experiments, Ca(OH)2 was formed by adding CaO to concentrates containing enough water to simulate filter cake from flotation circuit. This eliminated the need for drying the concentrate and utilized the heat of hydration of CaO.

Jan 6, 1972