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By Roland W. Merwin

The Bureau of Mines has studied the possibility of using the heap leaching process for treating the gold ores in the sedimentary beds of northeastern Nevada. This paper summarizes all available information on the technical and economic feasibility of heap leaching oxidized ores from these beds, past industry application of vat leaching, results of recent Bureau of Mines and industry tests on heap leaching ores from this region, and requirements for planning the proper application of heap leaching. Preliminary tests on representative samples of ores from the region show that a satisfactory recovery of gold can be obtained by heap leaching the ores with cyanide at a relatively coarse size. Significant deposits of gold ore occur in sedimentary beds of various locations over an extended area 40 miles wide and 200 miles long in northeastern Nevada. The area is centered 40 miles west of and runs parallel to the leading edge of the Roberts Mountain thrust fault system, a prominent geologic feature in the area. The general locations of past and present gold mining operations are shown in figure 1. (slide 1)

Jan 1, 1969

By F. W. Pereira

The Montana Talc ore body was discovered in the summer of 1983, in the Gravelly Range, approximately 25 miles south of Ennis, Montana. Initial drilling indicated a plus-million-ton ore body of high-purity talc. Preliminary analyses were performed on the ore cuttings, .including chemical analysis, brightness measurements, and microscopic evaluations of the structure of the talc. The results indicated the talc was similar to that currently being marketed from Montana and probably would have good commercial value.

Jan 1, 1989

By J. B. Hanlon

In order to protect coal mine owners, operators, and lending institutions from potential environmental liabilities, responsible parties must maintain a thorough understanding of the environmental disposition of the property they control, and the ramifications of impending laws and regulations. The best way to accomplish this is to periodically conduct a Phase I Environmental Audit. The systematic approach of an audit will reveal areas of DOD compliance with SMCRA and EPA regulations which the coal owner and/or operator will be able to use to correct deficiencies and prevent the occurrence of conditions which could lead to permit block, fines, and ultimately reduced productivity.

Jan 1, 1995

By John E. Tilton

Mining is one of the oldest human activities. It goes back at least to the Bronze Age and possibly even the Stone Age. The Romans mined copper in Spain and tin in England some 2,000 years ago. The writings of Agricola in the 16th century show that mining was important in the Middle Ages. Today, more mineral commodities are mined in greater tonnages than ever before. This long and fascinating history closely tied with the economic development of the human race is one of the charms of the mining industry. It also, unfortunately, gives rise to some widespread misconceptions. Old industries are generally considered stodgy with mature and stagnant technologies. Costs tend not to decline as in newer industries, and may even increase with real wages. Costs are particularly expected to rise in the case of mining as the best mineral deposits are depleted. Thus, mining is often thought of as a sunset industry, destined to decline over time as the resource base is depleted. These perceptions have several important implications. They argue against economic policies that rely too heavily on mining and mineral processing to foster growth and development. The best and the brightest young people, along with society's other valuable resources, should be encouraged to enter newer industries. There the technological opportunities and the prospects for growth are more promising. These perceptions also suggest that the ability to compete in the mining industry depends largely on the quality of a company's or country's mineral deposits. Mining will take place first in countries with the lowest-cost deposits. Once these are exhausted, mining will shift to countries with the next best deposits. From time to time, new discoveries may also produce a shift in the location of mining, [ ] and may even for a time keep the costs and prices of mineral products from rising. Over the longer term, however, rising costs and prices are inevitable, as the world is forced to exploit poorer mineral deposits.

Jan 1, 1997

By C. V. Deutsch, J. B. Boisvert, M. A. Cuba

The amount of information available for characterizing a deposit increases over time due to the continuous acquisition of data during mining. This additional information is collected from different sources, including geologic mapping, production data and infill drilling. Throughout the lifetime of a mining project, the block model and the mining sequence are periodically updated to account for this new data. In general, the acquisition of additional data increases the accuracy of the block model, reduces uncertainty in ore/waste limits and clarifies the optimal mining sequence. There has been extensive research on mine planning, but current techniques do not consider the decrease in uncertainty as additional information becomes available. Conventional paradigms assume either 1) the kriged model is correct and uncertainty due to multiple realizations does not change the mining sequence, or 2) the mining sequence is unrealistically adapted to each realization. A new paradigm is proposed for evaluating minable reserves of surface mining projects, which accounts for the acquisition of additional information in the design of the long term mine plan. Multiple scenarios characterizing the dynamic nature of mining and data collection are created. In the proposed methodology, the performance of the long-term mine plan depends on both mining and data acquisition strategies. Each scenario considers the same extracted volume for the first period, resulting in a set of scenarios that diverge from a common initial period, accounting for how the mine may develop over time as new data are acquired and provide a more realistic evaluation of reserves with an appropriate level of uncertainty. A synthetic example is presented to illustrate the implementation of the methodology and the benefits over conventional paradigms.

Jan 1, 2013

By Steve Kral

The mining industry has waited a long time for the resurgence in commodity prices and demand for its products that it is now experiencing. Base and precious metals prices have reached levels not seen before. Coal prices have also shot up. And there are encouraging signs in the uranium market. China’s nearly out-of-control economic growth is said to be the leading driver for much of this resurgence. But demand for energy, metals and building materials in the United States and elsewhere are also major factors. The result is that expansions and new mines for nearly every commodity are in the works.

Jan 1, 2005

By M. S. Miller

With prevailing assumptions that plentiful domestic coal reserves will be available for meeting our Nation’s expectations for on future low emission, coal-fired power plants, major government funding in Clean Coal Technology, and Carbon Sequestration Programs continues to be aggressive. However, after more than a decade of cutbacks in funding for domestic coal-related programs and personnel, there is a growing concern that adequate quantification and qualification of our Nation’s coal reserves is increasingly being compromised. This paper will define the growing concerns and dichotomies that continue to increase, and address the decreasing number of fossil fuel mapping and assessment programs by Federal and State programs.

Jan 1, 2004

By B. A. Kuyper

The Cove gold-silver deposit is located 50 km southwest of Battle Mountain, Nevada and 1.5 km northeast of the McCoy Mine. Total proven and probable reserves are 48.7 Mt (53.7 Mst) with an average grade of 1.85 g/t (0.054 oz/st) Au and 87.1 g/t (2.54 oz/st) Ag. Mineralization is hosted by Triassic carbonate and siliciclastic rocks in two separate orebodies. Oxide ore consists of disseminated gold and silver in clay-altered, manganese-flooded limestone. Sulfide ore is dominated by pyrite-sphalerite-galena veins in siliciclastic rocks and sandy dolomite. Gold and silver occur in the native state, associated with the base metal sulfides. Mineralization is interpreted to be the distal expression of a porphyry system. The McCoy gold (copper) deposit is interpreted to be the proximal expression of the same system.

Jan 1, 1991

By C. Clark, R. Pakalnis, B. Seymour, L. Martin, M. Stepan, M. Roworth, C. Caceres

The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health, Ground Control Engineering Branch is investigating the use of shotcrete in weak rock mass mines with the objective of reducing fatalities and injuries resulting from rock fall accidents. When shotcrete is used as part of a multielement ground support system, there is a need to know the support characteristics that the shotcrete contributes to the overall system. To quantify the support provided by the shotcrete, flexural strength tests were conducted with two common, commercially available fiber-reinforced shotcrete (FRS) mixes using the round determinant panel (RDP) test method, ASTM C 1550. A portable RDP test machine developed by NIOSH researchers was used to determine the peak flexural load and residual load capacity for a steel FRS and a synthetic poly FRS that were sprayed using dry mix procedures and equipment. Besides the flexural strength and loading behavior determined from these tests, a method was also developed for measuring the width of cracks exposed on the underside of a shotcrete panel during a RDP test and relating these measurements to residual load values. Quantifying the peak flexural load and residual loads of a shotcrete mix through on site testing at a mine and visually assessing the loading cycle and load-carrying capability of the shotcrete applied to underground workings will improve mine safety by providing a better assessment of the stability of shotcrete supported entries.

Jan 1, 2010

By Dianne C. Marozas

The U.S. Bureau of Mines is conducting research to evaluate the potential for developing an in situ leach mining process that will selectively extract manganese from oxide ores, leaving gangue relatively undisturbed. To accomplish this, a geochemical approach, based on deposit-specific information such as mineralogy and geology, is used to constrain the operating parameters of the system. Among the studies being conducted are (1) leaching experiments to define reaction mechanisms and kinetics, (2) detailed petrologic characterization at the microscopic scale to assess Mn distribution and leaching efficiencies, (3) deposit characterization and evaluation, and (4) development of potential Mn recovery schemes. Data from these studies are being used to develop engineering design information for an in situ mining process. Specific details of the Bureau's research project are discussed, including results obtained to date.

Jan 1, 1991

By Jan M. Mutmansky

Since 1973 when the first edition of the SME Mining Engineering Handbook was published, many significant changes have occurred in the US mining industry. The industry went through a fairly prosperous period immediately after 1973, but then many economic pressures came to bear on mining companies, particularly in the metal and coal branches of the industry. These pressures changed both the mining methods used and the general economics of the mining methods. As a result, the industry today is different in many ways titan it was in 1973. A general summary of some of the more important changes that have come about will be provided here as well as some assessment of the effects of these changes on the choices of mining methods. In the metal mining industry, the most significant trends were increased surface mining, the use of larger and more efficient equipment, and increased technology and automation. The primary impetus for these changes was unprecedented competition from foreign producers. In many cases, this competition came about because of the nationalization of foreign mines and the tendency for these mines to become a source of foreign exchange. Under these circumstances, the mines could be operated even though they were not profitable. As a result, domestic

Jan 1, 2008

By William J. Orlandi

The intent and scope of this paper is to present to you, as concisely as possible, the problems and requirements -- and what we consider advantages -- of all-belt haulage in a modern underground coal mine. Mine No, 10, at Pawnee, Illinois, was opened in 1951; consequently, all the planning and consideration given to haulage selection was based on information then available and on Peabody Coal Company? s experience to that date,

Jan 1, 1961

By W. J. Turbeville

The subject of this discussion is timely. The U.S. phosphate industry is suffering the throes of depression. It's plight is a matter of widespread concern. The future role of the U.S. industry in world markets is of particular interest. If we should prognosticate phosphate supply-demand on the basis of recent history, we would face a puzzling choice of scenario. In 1980, perhaps the best year ever for U.S. phosphate, 54.6 million metric tons of phosphate rock entered the market place. Of this, more than half was exported -- divided almost equally - as rock or phosphate fertilizer. During the last half of 1981 the situation had begun to change.

Jan 1, 1983

By A. Robison, V. T. McLemore

"The San Juan Basin, New Mexico contains many heavy mineral beach-placer sandstone deposits of Cretaceous age. Beach-placer sandstone deposits are concentrations of heavy minerals that formed by mechanical concentrations (i.e. settling) of heavy minerals on beaches or in longshore bars in a marginal-marine environment. They have high concentrations of several elements, such as Ti, Zr, rare earth elements (REE), Sc, Y, U, Th, Nb, Ta and Fe. These elements are becoming increasingly more important to industry, because they are used in the manufacture of devices our society uses every day, i.e. cell phones, computers, and alternative energy devices, like solar panels. It is unlikely that any of the beach-placer sandstone deposits in the San Juan Basin will be mined in the near future because of small tonnage, low grades, high iron content, and distance to processing plants and markets. However, as the demand for some of these elements increases because of increased demand and short supplies, the dollar value per ton of ore rises, enhancing deposit economics. Current studies at the New Mexico Bureau of Geology and Mineral Resources are focused on the Apache Mesa (formerly Stinking Lake) deposit near Dulce, New Mexico. INTRODUCTION Beach-placer sandstone deposits are accumulations of heavy, resistant minerals (i.e. high specific gravity) that form on upper regions of beaches or in long-shore bars in a marginal-marine environment. They form by mechanical concentration (i.e. settling) of heavy minerals by the action of waves, currents, and winds (Fig. 1; Bryan et al., 2007). Modern examples are found along the Atlantic Coast, USA (Koch, 1986; Carpenter and Carpenter, 1991), southeastern Australia (Roy, 1999), and Andhra Pradesh, India (Rao et al., 2008), where they are mined for titanium, zircon, and monazite (a Ce-bearing rare earth, REE, mineral). Detrital heavy minerals comprise approximately 50-60% of these sandstones and typically consist of titanite, zircon, magnetite, ilmenite, monazite, apatite, rutile, xenotime, garnet, and allanite, among other minerals. Most of these minerals have a high specific gravity exceeding 4 and are dark colored, giving the sandstones a dark color, resulting in them being called black sandstones. Although beach-placer sandstone deposits are found in strata of all ages; the deposits in the San Juan Basin in New Mexico are restricted to Late Cretaceous rocks belonging to the Gallup, Dalton, Point Lookout, and Pictured Cliffs Sandstones (Fig. 2; Table 1; Chenoweth, 1957; Houston and Murphy, 1970, 1977). The beach-placer sandstones are black, dark gray, to olive-brown, resistant to erosion, and radioactive due to radioactive zircon, monazite, apatite, and thorium minerals. Anomalously high concentrations of Ti, Fe, Nb, Th, U, Zr, Sc, Y, and REE are characteristic of these deposits. Similar Upper Cretaceous heavy mineral, beach-placer sandstone deposits are found throughout Montana, Wyoming, Utah, Arizona, and Colorado (Dow and Batty, 1961; Houston and Murphy, 1970, 1977; Zech et al., 1994)."

Jan 1, 2016

By Robert H. Raring

Viewed abstractly, a mill may be defined as a mineral processing facility located somewhere between the mine and the tailings storage area, Just how mining operations and the demands of tailings storage affect mill design is, the subject of this paper. At the outset, it will be readily acknowledged that no two installations can, or ever will be the same. At one extreme is the bucket line dredge where the distance between the ?mine? and the tailings area is measured in terms of tens of feet. At the other extreme, the large open pit copper mines are frequently spread across twenty, miles or so of countryside with the ore moving to the mill, as exemplified by the operations at Bingham Canyon, Ray, or Ruth - the "upstream" counterparts of Garfield, Hayden and McGill. In each of these cases, mill location was largely determined by requirements for tailings storage and/or water supply.

Jan 1, 1961

By Brian W. Mackenzie

The mine development decision is made on completion of exploration to determine whether or not a mineral deposit should be developed to production and, if so, how. This involves the selection of an optimum mine development alternative from a number of technically feasible alternatives and the comparison of this optimum with those of other available investment opportunities. If the optimum is sufficiently attractive, the deposit is developed to production. The selection process is carried out within a framework of corporate objectives and resources. The mine development decision is based on the balancing of two parameters - - rate of production as reflected in plant capacity and cut-off grade. On the basis of available information and experience, detailed revenue and cost 'estimates are made for each feasible combination of plant capacity and cut-off grade. What economic evaluation techniques should be applied to these estimates to reduce each alternative to economic indicators that will enable meaningful comparisons and an informed investment decision? This is the essence of the paper. The determination of optimum plant capacity and cut-off grade has been the subject of intensive research efforts by economists and mining engineers (1-7). Their studies are based on marginal analysis and assume that, at the time of decision, certainty conditions prevail with respect to ore reserves, mining costs and mineral markets. The optimum mine development alternative is defined as that which maximizes profitability.

Jan 1, 1969

When it comes to safety in the mining and extractive industries, success is literally a matter of life and death. Anything short of perfection is not acceptable. In recent years, the mining industry in the United States has made tremendous strides in terms of health and safety for its workers. Part of that success has come with an increased focus on the issues of safety, an intense examination of procedures, liberal sharing of best practices and a focus on the synergy between safety, reliability and environment. During his closing keynote address of the Safety Management & System Reliability Conference in Minneapolis, MN on Nov. 15, Joe Driscoll, vice president of Great Basin Gold, showed a calendar from the coal fields in Pennsylvania from the early 1900s. The calendar marked the number of mine-related deaths each month. Some months, the number was as high as 50. It was an illustration of how far things have come, but there is still much more work to be done.

Jan 1, 2013

By Nancy Bingham

The mining industry’s image is molded by what the public knows, or thinks it knows about mining. As Caterpillar prepared for the production of its educational video, Common Ground, the public’s perceptions about mining needed to be established. Before we could educate people about mining, we had to find out what they already thought. As those perceptions were analyzed, we were able to narrow the video’s focus to relevant, realistic approaches. We found out what people did not know about mining. And, most importantly, facts they should know were singled out - facts that could create more favorable attitudes. This research was instrumental in the final direction of the Common Ground project. What the public believes As these perceptions about mining were researched, it was found that the beliefs of the general public are dominated by four concepts. Quotations from interviewees are included with the discussion of each of these concepts. Figure 1 shows an overview of people’s beliefs before education.

Jan 1, 1994

By Michel Dagbert

In the exploitation of porphyry-type deposits, the quality of the ore is mostly defined according to its grade. Besides the simplest distinction, ore-waste, several grade categories may exist and they correspond to the different ways in which the ore is further processed. At the time of mining the selection of the different categories is done from extensive information available from blast holes. But planning has to be done before this information is available and it is necessary for the geologist to forecast, from exploration and development data alone, the possible outcome of the selection done later on a block, a level, or the whole deposit and ultimately predict the ore reserves and value of the deposit. A good statement of this problem has been presented at the 1976 AIME annual meeting by Williamson and Hueller (1976). They have shown that, if the cut-off values are directly applied to the estimated grade of blocks, a gross overestimation of the recovered tonnage of ore (14%) will occur. This problem, now termed "the vanishing tons problem" (DaVid, 1977) seems to be common in many open-pit operations and it has been explained several times (DaVid, 1972; Huijbregts, 1975). In order to solve it l.Jilliamson and Mueller proposed a solution based on compiling masses and masses of blast hole data available from mined-out portions of the deposit. They derived empirical correction factors which provide for every block, given its estimated grade, the expected tonnage and average -grade of each category of material within that block. The purpose of our work is to repeat the same exercise but ignoring the blast holes data i.e. we want to derive the correction factors from the only DOH data. Doing this, we are more in the real conditions where the valuation of the mine and are reserve analysis has to be made before production actually starts. Two possible ways to achieve this goal will be investigated and the emphasis will be on recently

Jan 1, 1977

By Ronald L. Wiegel

In the 2000 page Handbook of Mineral Dressing by A. F. Taggart, the subject of material or metallurgical balances is covered in only six pages of eve-straining type. Although Taggart's work was compiled before 1945, and there has been significant progress since then in most areas of mineral processing, the practicing metallurgist's approach to metallurgical balances remains exactly the same as described in those six pages. There are several portions of Taggart's text appropriate to introduce the subject of this paper which I would like to quote: "Milling Calculations. Computations of per¬formance in milling are complicated by the fact that it is a continuous rather than a batch operation, that the quantities of solid materials handled are large and usually mixed with water, hence difficult or impos¬sible to weigh. Fortunately it is possible to determine many facts concerning perfor¬mance without knowing weights, if the value of various constituents is known in some common unit, e.g., the content of some par¬ticular metal or mineral, or of water, or some ingredient soluble therein, or of par¬ticles of a particular size or falling within some particular size range, or the like."

Jan 1, 1979