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By Thomas J. Peters

At the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines and U.S. Geological Survey conducted a mineral investigation of about 85,470 acres of the Diablo Mountain Wilderness Study Area, to determine mineral resources and mineral resource potential. The study area is in Lake County Oregon, about 45 miles northwest of Lakeview. Fieldwork was conducted in 1986, 1988, and 1989. Geologically, the study area lies on the northwest edge of the Basin and Range physiographic province, a region of fault block-formed mountains and basins characterized by interior drainage. Consolidated rocks are mostly Tertiary basalt and tuffaceous sedimentary rocks. Low-lying areas are covered by Quaternary alluvial-fan, sand-dune, playa, lacustrine, and landslide deposits. The principal structural features are normal faults that have large vertical offsets; these faults are typically concentrated at the margins of large horst and graben. The 34,310-acre "additional," or western part of the area was mainly studied in 1988 and borders the east shore of saline Summer Lake. In this portion of the study area there is potential for undiscovered resources of soda ash, boron compounds, and sodium sulfate as well as by-products, which include magnesium compounds, salts, potash, bromine, lithium, and tungsten associated with brines. No energy or mineral resources were identified in the study area, but brines within lake and playa sediments contain concentrations of chemical components suitable for the production of soda ash, boron compounds, and sodium sulfate. Possible by-products include potash, salts, bromine, lithium, magnesium compounds, and tungsten. Limestone from the study area could be used in the recovery process of brine components or agricultural uses. The study area includes thermal springs and lies within 2 miles of the Summer Lake Known Geothermal Resource Area. Local production of geothermal power by the binary process may be economically feasible. Soda ash, soda ash products, and boric acid are widely used in fluxing metals, and have important applications and markets in the aluminum industry in the northwest and the developing Chinese counterpart. Evaporite commodities are essential to many "backbone" industries, and to many new applications and advanced materials. Markets for brine mineral products appear to be undergoing steady and strong growth, especially in the Pacific Northwest and in Pacific Rim countries. Soda ash produced near the study area would be 55 percent closer by rail to marine export at Portland, Oregon, than trona deposits of the Green River District (Wyoming). Soda ash and a daughter product, caustic soda, and sodium borohydride will receive increased application in the bleaching of paper pulp for environmental reasons. Caustic soda, used in many industrial processes, is more environmentally friendly when derived from soda ash than when produced from sodium chloride salt, because of the absence of a chlorine by-product. Producing soda ash from brines, a type of in situ" mining, can be done with minimal environmental degradation, and mining natural soda ash is environmentally as well as economically preferable to synthetic soda ash production.

Jan 1, 1995

By C. E. Jordan

The Bureau of Mines conducted research to measure the improvement provided by fine bubbles on the flotation of fine-sized particles (minus 20-um size) in an effort to improve flotation efficiency in our domestic minerals industry. The turbulent velocity distributions of the fluid within the flotation cell were measured as a function of time and position and used to increase the precision of a fine particle, turbulent flotation model. For the mineral system investigated, improved flotation response was obtained under laboratory conditions by using small bubbles and intense agitation. These results matched the model's predicted response.

Jan 1, 1989

By K. Kim, T. M. Yegulalp

A numerical model is being developed to assess the enhancement of ore permeability by improving fracture connectivity with micro-hydrofracturing. As part of this project, a generic two-dimensional percolation model was developed to test the impact of various field conditions on permeability. Field data from Cyprus Minerals' Mineral Park mine was used to establish the statistical properties of the observed fracture systems. Results of statistical analyses of field data and examples of the use of the percolation model are presented

Jan 1, 1997

By D. E. Wolfson

As energy requirements in the United States expand with the growth of the Nation, use of coal also can be expected to increase. This optimistic outlook for the coal industry is based on our vast reserves of high quality coals and the possibility of converting coal to end uses other than electricity and metallurgical coke. Potentially, millions of tons of coal might be needed in the form of gas and liquid fuels to supplement our reserves and imports of these natural products. Exactly when they will enter the economy on a large scale depends on many factors. On January 1, 1960, the estimated remaining reserves of coal were 1-1/2 trillion tons, about 50 percent of which is bituminous coal. In 1965, the production of bituminous coal and lignite passed the 500-million-ton mark, emphasizing the steady upward trend from the recent low of 403 million tons, and if the present rate of increase continues within the next five years, output should pass the alltime high of 631 million tons achieved in 1947.

Jan 1, 1969

By Roger S. Dewey

1.1. INTRODUCTION Despite indications of a general economic recovery in the U.S. during the mid-19801s, mine operators have not generally shared in the benefits of these reported better times. Budgets have not rebounded, borrowing is tougher, parent companies' pockets are not as deep as in previous years, and margins are not any better -- if there is any left over at all. Managing capital equipment budgets is always a challenge, and the last five years of stretched equipment lives make these decisions more tenuous. Delays and avoidance of replacements due to tough times inevitably makes those decisions increasingly difficult and usually more expensive The purposes of this paper are to present. a brief refresher outline of the fundamentals of equipment replacement analysis, to suggest a number of papers where analysis methods are explained in greater detail. and to recommend the use of a widespread microcomputer software capability (1-2-3) as the easiest path to a much-needed solution for a very difficult, and usually under-supported management decision problem 2. REPLACEMENT DECISION POLICY Investments in equipment replacements must compete for capital with all other investment alternatives. Capital for replacements of ten represents a greater commitment than do the new projects which a company might handle in a given year. But. sadly, formal policies for standardized analysis of replacements rarely exist, even in major companies. Yet this policy can be very significant in determining the competitiveness of a firm. Whereas many replacement decisions are based on cost minimization, economists and financial analysts agree that wealth maximization or return on investment is the superior criterion. Though the difference may seem slight, agreement on a firm's financial objective is vital. Replacement policy should be straight- forward. have a logical basis, and a proper level of sophistication. There are several reasons to develop a policy for replacement decision-making: [I] 1 - equipment's optimal economic life is nearly always shorter than its physical life; 2 - mine life often exceeds equipment life, so management must face these decisions routinly 3 - replacement capital costs, on an undiscounted basis, can run 25 to 75% of original capital 4 - technological changes may result in a newer machine or system which can operate more efficiently, more safely. or less expensively 5 - estimates should be made consistently in the fundamental areas of life expectancy, availability, utilization. price escalation, taxes 6 - long-term and short-term budgeting without decent data and analytical capability is nearly impossible, or at least ineffective Policy development assumptions which must be considered include: the planning horizon, cost patterns, interest rates, availability of capital, replacement vs. expansion, technology advances.

Jan 1, 1987

By K Timtner

As shown in former publications there are problems in load sharing of backstops in multiple drives of conveyors. Therefore, detailed calculation methods and design recommendations are required. In this paper various designs of load sharing methods are described and a dynamic torque calculation method will be presented. With this method the loadsharing properties for low and high speed backstops are calculated and compared. These properties depend on the spring characteristic of the drive train between backstop and load. Furthermore, the properties depend on the method of torquearm support and shock absorber configuration. Remarkable differences for external and internal backstops are shown

Jan 1, 1998

By Jon Y. Kaneshiro, Donald W. Scapuzzi

The primary purpose of the Prototype Installation Facility (PIF) for the Superconducting Super Collider (SSC) in this conceptual design was to test the magnets and other physics equipment. PIF was located in the northwest quadrant of the SSC 54 mile (87 km) main ring and consists of the first segment of tunnels, approximately 17,060 lineal feet (5.2 km) of 12 foot inner-diameter (ID) (3.7 m) tunnel, three 250 ± foot (60 m) deep shafts, connecting tunnels, and associated niches and alcoves. PIF would be the first portion of the main ring collider tunnel to be constructed. The geology, underground excavation conditions, underground facilities, and contractual considerations are discussed.

Jan 1, 1991

By J. F. Brune

"Re-occurring face ignitions in U.S. coal mines are concerning and require a closer look at air quality monitoring systems and practices employed in these mines. The explosion disaster at the Upper Big Branch mine in West Virginia in 2010 caused 29 fatal injuries and was largely caused by inadequate water sprays and inadequate ventilation monitoring. In this comparison, the author compares ventilation system monitoring in Australian, German and U.S. underground coal mines and makes recommendations for improvements and best practices. Mines in Germany and Australia are adhering to more stringent requirements for monitoring air quality and quantity and for monitoring water spray systems on cutters to prevent frictional ignitions. Air quality should to be monitored for sufficient oxygen, toxic gases, explosibility and for fire gases indicating a potential fire. Ventilation monitors must also confirm that sufficient quantities of air are available. Fully automated, continuously recording atmospheric monitoring and alarm systems are established practices in Germany and Australia and should be mandated for U.S. mines as well, in addition to the current, regular spot inspections of the ventilation system by certified mine examiners. BACKGROUND: METHANE EXPLOSIONS, FACE IGNITIONS AND NEED FOR AIR QUALITY MONITORING Accumulations of methane in face areas of underground coal mines frequently lead to ignitions that can cause burns, traumatic injuries and, in the case of the 2010 Upper Big Branch disaster, cause major explosions with multiple fatalities. Table 1 shows the number of reported face ignitions in U.S. coal mines between 2010 and 2014, based on statistical data published by MSHA (MSHA 2010 – 2014). Although there appears to be a downward trend in such ignition incidents over time, ignitions continue to occur with some regularity; and each ignition may cause a potentially catastrophic mine explosion.Per regulation, all U.S. coal mining machinery, continuous miners and longwall equipment, is outfitted with continuously monitoring methane sensors wired to cut power to the equipment as the methane level exceeds 1%. Face ignitions keep occurring because these sensors are usually not positioned in sufficiently close proximity to the coal cutting drums or to the freshly exposed coal face where the methane is most likely released. Therefore, methane may accumulate in explosive concentrations near the coal face and the cutting drums long before the gas concentration reaches the 1% level near the monitor and creates an alarm."

Jan 1, 2016

By H. Colijn

The ever increasing price of bulk commodities forces buyers and sellers in world markets to take a more careful look at methods for obtain¬ing accurate accounting of commodity trans¬actions in commerce and material utilization in processes. Depending upon the application of a sampling and weighing system or the use intended, inaccuracies can result in an eco¬nomic loss of income or a loss in quality of the process. It inevitably results in a loss of control of ones costs. The accuracy of samp¬ling and weighing systems is today extremely important, as they are recognized to be the key components of the overall management system designed to provide both quantitative and qualitative control. This paper will be confined to the weighing systems only and will deal with various as¬pects of system design, calibration and opera¬tions. Special emphasis will be placed on new developments and requirements in this field.

Jan 1, 1988

By M. Misra, J. Nanor

The removal and stability of arsenic over a wide pH range (3.0-10.0) from synthetic solutions and industrial waste effluents (including mining waste tailing slurry) can be accomplished with addition of impure lanthanum chloride alone or in conjunction with ferric sulfate. The long term stability of these correspond­ing precipitated compounds is critical from the disposal stand­point. In this paper test results of this new process for arsenic removal and stabilization from the above mentioned systems are presented. Also, precipitated arsenic compounds (lanthanum arsenate, lanthanum-ferric arsenate, ferric-lanthanum arsenate and ferric arsenate) from synthetic solutions have been charac­terized. The characterization technique used was XRD. XRD patterns which shows that the lanthanum arsenate and lan­thanum-ferric arsenate formed in acidic and alkaline pH at room temperature are crystalline. On the contrary, ferric arsenate and ferric-lanthanum arsenate compounds formed under the same conditions as lanthanum arsenate were amorphous.

Jan 1, 1998

By David R. Wayman

This paper summarizes environmental compliance and related issues associated with underground construction and tunneling operations, whether new work or rehabilitation. Underground construction and tunneling operations have (in most cases) both an underground and surface component. Since many of the major tunneling projects occur in urban areas, often is areas inhabited for several decades or centuries, environmental problems may already exist in a project area, though that may not yet have been formally recognized. Large projects often attract more than their fair share of regulator attention. This paper addresses the issues with the greatest potential to be encountered by underground constructors, with the emphasis on minimizing contractor liabilities, both in the short- and long-term. Minimizing contractor liability begins with understanding bid documents, contract provisions and necessary means of protection, and carries through project execution by responsible control of hazardous materials, avoidance of media contamination, proper waste disposition, as well as compliance with other environmental requirements.

Jan 1, 1999

By A. Dan Rovig, C. Kevin McArthur

Technical and managerial innovations in the minerals industry have allowed continuing mining activities in the United States, and elsewhere, as gold orebody quality has diminished or has become more refractory. Of course, world markets, permitting requirements, and political processes also have created a need for innovative practices that contribute to the survival of the mineral industry. The gold industry has been transformed, during the past approximately 40 years, from a predominantly underground mining and milling type of exploitation and extraction to the large-scale, relatively low-grade type of extraction that is common in the United States today. Indeed, with the introduction of gold heap-leaching technology and the development of mines that produce from large, relatively low-grade gold orebodies in the western United States, a "new" industry was born and continues to prosper today. It is worthwhile noting, however, that Dobra (1997) has reported that one of the major trends in the North American gold industry is a movement back toward underground developments.

Jan 1, 1998

By Steven G. Vick

Not too long ago a mill superintendent, when asked where his tailings were being disposed, could simply shrug his shoulders and point to the open end of the thickener discharge pipe. This “out of sight, out of mind” approach to tailings disposal is a practice of the past. Today there are very few planned hardrock or energy-related mining facilities where tailings disposal has not been identified as the major area of impact and controversy. In fact, development of some ore bodies has been stymied altogether by lack of suitable sites or methods for tailings disposal. The bottom- Iine result is that tailings disposal often controls the permitting lead time and has a significant influence on construction cost (up to 2070 in some cases) of new minemill complexes. The following article, the first in a series of three, explores technical background and historical perspectives on siting and design of tailings impoundment facilities.

Jan 6, 1981

By David Logan, Sigurdur Finnsson

This project, which is intended to provide effective sewerage services to the Blue Mountains community, is located in the Blue Mountains National Park, about 60 km west of Sydney, Australia. The sewerage scheme consists of about 40 km of tunnels, out of which approximately 22 km have been completed. This paper describes the last major tunnelling operation on this project, the Hazelbrook to Katoomba tunnels. These tunnels, which mainly traverse the Hawkesbury Sandstone formation, are being excavated by a new 3.4 meter diameter Jarva Mk12C TBM. The mucking system consists of a continuous conveyor, which has allowed for some very impressive advance rates. The paper will consist of three main sections; the general geological conditions expected along the tunnel will be described in the first section. The second section will discuss the design and main features of the TBM, back-up system and continuous conveyor. The third section of the paper will describe the operational aspects and various performance data of the machine.

Jan 1, 1995

By William A. Holgate

Coal production in the in the Powder River Basin began its tremendous expansion during the boom of the mid-1970s. New mines were opened from 1976 through the early 1980s. This expansion soon placed Wyoming at the top of the list of coal producing states, where it has since remained. Mines are operated by large companies, with safety and production having equal priority. These mines have been some of the safest ever in the coal industry. Many Sentinels of Safety Awards have gone to them. Safety programs are varied, but there are commonalities. Mine safety at Wyodak Extra training is required of all supervisors. The company offers to pay for any additional first-aid training that employees participate in. Safety departments conduct weekly safety talks. All employees receive the monthly magazine Family Safety and Health compliments of Wyodak. Electricians receive extra training on electric wheel motors, from General Electric. Equipment operators receive extra training from Dresser.

Jan 1, 1994

By Robert L. Cascio

The mining industry uses a large amount of electric power. Their equipment is subject to extreme environmental conditions and mechanical shock. A significant number of electrical accidents are a result of improperly grounded electrical equipment. Federal regulations require the safety ground bed resistance to be measured once a year or after modifications. Most commercially available instruments used to measure the ground bed resistance require the ground conductor to be disconnected and the power system disconnected for safety reasons. The "fall of potential1' method requires auxiliary ground rods and approximately two hours to complete the test. Although a new instrument was initially thought to measure the ground bed resistance immediately without isolating the ground bed, field tests have shown this method is not accurate. In some cases, a continuous measurement of the ground resistance is desired. A monitor has been developed and is presently being evaluated at several mines. These installations will be discussed.

Jan 1, 1992

By Charles T. Staniek

Following a dragline relocation at Agrico's Fort Green phosphate mine in 1986, the recovery plant experienced a significant decrease in flotation performance. Through weeks of trial and error testing, we discovered we could restore recoveries by conditioning feed at pH's higher than we had used historically. The higher pH's essentially increased flotation cell kinetics, although we still do not understand the exact mechanism at work. Armed with new-found appreciation of pH modification, we initiated a program to determine the optimum modifier for us, from both a performance and environmental perspective. Environmental considerations were important because ammonia, the standard industry modifier, is a plant nutrient and higher usage rates could affect the quality, of our recycle process water. This paper describes the research and development work spanning a 3 year period that culminated in making a major change in our reagent suite when we replaced ammonia with soda ash on a permanent full-time basis.

Jan 1, 1993

By S. A. Moffatt

For several years iron ore processing plants, located in the northern U.S. experienced seasonal decreases in the grinding efficiency of their primary autogenous mills. Kawatra and Eisele (1992) studied this phenomenon in an operating plant and characterized it in terms of specific energy consumption (Fig. 1) and production of critical size material (Fig. 2). Critical size material is defined as ore that is too small to be effective grinding media and too large to be ground. This data showed that both specific energy consumption and critical size production increased during the winter months. The increased energy consumption was in part a result of an increase in the viscosity of the mill pulp at colder pulp temperatures. However, viscosity could not fully explain the changes in critical size production. These changes are most likely due to changes in the breakage characteristics of the ore. Other studies were also conducted to determine if thermal and physical properties of iron ore changed at colder temperatures. These are summarized below:

Jan 1, 1993

By M. ]. [Mohkam

The paper describes the features of the problems encountered and the countermeasures taken for two different tunneling projects. Where, slurry shields were used to excavate, in soft heterogeneaous water-bearing grounds, tunnels passing at very low cover beneath existing foundations of H.T. electric pylons, underground structures and major utilities. In order to avoid any ground failure and/or damage to the existing structures, one option was ground treatement by grouting or freezing technics. However, it was judged that, based on previous experiences, excavation with slurry shield could be carried on securely using an appropriate slurry enriched with polymers and applying a well determined pressure at ground face. A three dimensionnal limiting equilibrium analysis model was used to determine proper confinement pressures. And, the appropriate slurry compositions were stabilished based on laboratory test results. The tunnels were excavated successfully, no ground failure was experienced, and the maximum settlement recorded (on pylons) didn't exceed 3 mm.

Jan 1, 1991

By Frank W. Bowdish

Studies of sulfidization and flotation of chrysocolla involving the use of pH and sulfide ion instruments, a Zeta meter, microflotation techniques, and sensitive determinations of adsorbed sulfur have given new insight into the mechanism of the process. Factors that affect the recovery of sulfidized chrysocolla by flotation appear to be the pH at which it is sulfidized, and certain alterations of the surface that occur during aging after sulfidization. Such aging results in increased recoveries. The surface charge, as measured by electrophoretic mobility, of chrysocolla shows an unexpected negative increase as pH values are changed from 6.0 to about 4.5, and this appears to be correlated with increasing sulfur adsorption and flotation recovery over the same or even wider pH ranges.

Jan 1, 1970