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By Peter Zhang, Daniel Su, Mark Van Dyke, Heather Dougherty

The integrity of shale gas wells in longwall chain pillars under the influence of longwall mining is a safety concern for both coal and gas operators. Previous modeling studies of gas wells in longwall pillars have shown that a FLAC3D model can predict longwall-induced stresses and deformations in gas well casings with reasonable accuracy. The predicted casing deformations can be verified by multi-finger caliper survey. This study concerns the influence of longwall mining on eight shale gas wells in a shale gas well pad located in the chain pillars between two adjacent longwall panels under 1,030 feet of cover. FLAC3D modeling was performed to predict longwall-induced deformations in gas well casings based on site-specific mining and geological conditions. Small deformations less than 0.5 in were predicted in the intermediate casing above 600 ft depth, and very small casing deformations less than 0.15 in were predicted below 600 ft due to high abutment pressure and high frictional resistance along the weak bedding interfaces. After the first panel was mined, a 56-arm caliper survey was performed on one of the wells to measure the longwall-induced casing deformations in the intermediate casing. The predicted casing deformations were then compared with the measured deformations, which indicated that the prediction was generally in good agreement with the measurement in terms of deformation locations and magnitudes. Findings from this study provide valuable information not only for stability assessment of shale gas wells in longwall chain pillars but also for developing engineering guidelines to preserve casing integrity through adequate pillar and casing design.

By R. Day

Nahcolite is a naturally occurring sodium bicarbonate mineral found principally in the Piceance Creek Basin of northwest Colorado. An 8-m thick nahcolite bed, 610 m below the surface, is the target of this first commercial nahcolite mine. A chamber and pillar mining system is developed by solution mining parallel 8-m tall by 18-m wide by 450-m cavities initiated along horizontally drilled holes. Hot water leaching, cooling crystallization and flash drying is the process. The sodium bicarbonate product is consumed by the baking, animal feed, industrial and acid rain abatement markets. A project overview, emphasizing the combination of horizontal drilling and solution mining technologies, will be presented.

Jan 1, 1994

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 two thousand years ago. The writings of Agricola in the 16th century show that mining was important in the Middle Ages. Today we mine more mineral commodities 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.

Jan 1, 1997

By T. J. McKeon

Gravity separators such as spirals are commonly used in multistage cleaning and scavenging circuits to improve the quality and recovery of concentrates produced in the industrial minerals industry. Unfortunately, field surveys suggest that many industrial operations are poorly configured in terms of equipment layout. This shortcoming can often be attributed to a failure by engineers to make use of fundamental process engineering tools for circuit design. One of the most important of these is linear circuit analysis. This powerful tool makes it possible to mathematically compare the relative efficiency of circuit configurations in advance of experimental testing. This article provides a basic review of the linear circuit analysis concept and discusses some of the key insights it provides for the layout of multistage circuits. An industrial case study is provided to show the tremendous impact that this process engineering tool can have on the design of multistage spiral circuits in a heavy mineral wet plant.

Feb 1, 2012

By J. J. Antony

As the first wave of precious metal heap leach closures and reclamation projects occur, a number of companies are being hit with costly surprises. While this paper refers specifically to U.S precious metal projects, it could be conceptually directed at copper leach operations and acid rock drainage (ARD) problems on an international basis. ARD is Mother Nature's version of heap leaching, only with different products and timing. Although many precious metal deposits tend to be small in comparison with some base metals systems (porphyry copper deposits), adjacent or nearby discoveries have extended the operating lives of numerous precious metal mines. Now, depleted reserves, several years of relatively depressed precious metals prices and some properties with technical difficulties have resulted in numerous mine closures. As a result, our industry is getting a diverse and comprehensive initial look at mine closure and final reclamation. The situation has been further complicated by the evolutionary trend in regulations and their enforcement and increasing public and political awareness of all environmental issues. Concurrent (proactive) vs. deferred (reactive) reclamation and a realistic early appraisal of ultimate reclamation and closure requirements, not just regulatory compliance, need to be a part of project design. The U.S. and Canada are the current fertile testing grounds and have set the design, regulation and closure standards for the next wave of operations in Latin America, the CIS (?), etc.

Jan 1, 1994

By D. W. Park

Artificial intelligence has emerged over the past two decades as an important problem-solving tool including techniques such as expert systems, neural networks, tree classification, fuzzy logic, genetic algorithms, etc. These methods can be employed to solve rock mechanics and ground control problems associated with the highly complex nature of rock masses and ground conditions. A current study at the University of Alabama focuses on development of an artificial intelligence system for real-time interpretation of the data collected from longwall monitoring stations, and development of an early warning system for prediction of undesired conditions and prevention of longwall-mine instability problems. This paper describes a ground control management system using UALSAS (The University of Alabama Longwall Stability Analysis System), which is being developed to facilitate maintenance, on-line analysis, prediction, and includes an early warning system. A detailed framework of computer algorithms and their applications are also discussed. The successful application of these artificial intelligence techniques will contribute to a safer and healthier mining environment.

Jan 1, 1995

By A. J. Lewis, P. J. Hutcheson, M. E. Robertson, P. A. Moir, K. M. Barfoot

With the content of gold and platinum in the vast majority of ore deposits typically averaging 6 parts per million and less, the accurate and precise measurement of these metals in samples of ore and mining process streams has proven very difficult to achieve by modem spectroscopic analytical techniques. Largely because no other technique has proven suitable, the basic fire assay process has become the accepted international standard for these metals. Fire assay, however, suffers a number of disadvan­tages in the modem, competitive, high technology, and increas­ingly environmentally aware world. It is a labour intensive technique that is difficult to automate, and requires high levels of skill to ensure accuracy and consistency of results. Potentially hazardous chemical reagents are employed, of which, lead, in particular, can be a serious source of contamination to both personnel and the environment if not effectively controlled. Other dangerous elements, such as mercury and arsenic, liberated in high energy furnace operations, are further sources of possible health and pollution hazards. n contrast, the energy dispersive K X-ray fluorescence (K­XRF) technique devised by K X Technology Ltd overcomes many of the technical constraints of conventional low energy X­ray analysis, and has the potential to revolutionise assay opera­tions in precious metal mining. The technology is simply automated, requires basic operator skills, uses no chemicals, consumes less than 20kW, and is capable of detecting gold and platinum to an accuracy of O .1 parts per million by mass. The new third generation design of AZTEC laboratory instrument, released in 1994, is the result of significant technical development. Capable of analysing over 1200 samples per day, and developed primarily for grade control sampling, its applica­tions have spread to gold ore accounting from on-line conveyor belt sampling; screening of exploration samples; measurement of gold in carbon granules for Carbon-in-Pulp process control; and for conducting rapid checks to support key managemen decisions. The economic, rapid, and non destructive analysis ofup to 80g of ore for large numbers of samples, reduces sampling and sub-sampling errors, and provides improved grade estimates for ore bodies. When interfaced to a LIMS, laboratory automation and cost-savings can be further enhanced. The AZTEC design is also being modified for the analysis of platinum. The GOLDSTREAM on-line analysis system is an important new application of K-XRF to the continuous monitoring of process streams in gold ( or platinum) plants and mills. Integrat­ing the technologies of K-XRF to measure total gold, and dissolved gold spectroscopy to measure gold in solution, the insoluble fraction of gold can be deduced, and the effectiveness of the extraction process determined. Slurries are sampled automatically from selected points of the plant and pumped to the system for analysis. The information produced forms the basis for plant control and optimisation.

Jan 1, 1995

By M. E. Grimes

The Port Radium mine of Eldorado Mining and Refining Limited, located on Great Bear Lake only a few miles from the Arctic Circle in north-western Canada, is the oldest uranium producer in Canada, The first concentrates were produced in 1933 and except for a period between 1940 and 1942 the mill has operated continuously. Although it is located in a remote area, and compared to more recent mines in other areas is a small tonnage operation, nonetheless the relatively high grade of the Port Radium ore has permitted operation to date on an economical basis. The mill process at Port Radium includes the original gravity concentration mill, and since 1952 an acid leaching plant which treats tailings from the gravity mill and tailings recovered by dredging of residues from underwater dumps in Great Bear Lake. The pregnant solution from the leach plant has to date been processed through aluminum reduction to yield an intermediate grade uranous phosphate-arsenate precipitate, Because of the rising costs of the aluminum reduction process, and its sensitivity to ore composition, Eldorado became interested in possible application to Port Radium of the solvent extraction processes of which we were obtaining increasing information in the latter part of 1954 and during 1955.

Jan 1, 1958

By D. J. Boron, R. Kollrack

Introduction The US has the largest total (364 Gt, or 401 billion st) and recoverable (182 Gt, or 201 billion st) coal reserves in the world (Steam/Its Generation and Use, 1978). However, progressive coal use in this country has been hampered by environmental constraints, such as restrictions on sulfur dioxide, nitrogen oxides, and particulate emissions. Since the promulgation of the Environmental Protection Agency (EPA) New Source Performance Standards (NSPS), it has become apparent that all US coals will require sulfur removal to comply with the new sulfur dioxide emission levels. If more stringent emission standards are imposed, through pending acid rain legislation or amendments to the Clean Air Act, it is likely that the coal industry, and the industrial and utility sectors will look increasingly toward the development of new and advanced coal cleaning technologies to continue and promote the use of coal. Table 1 summarizes the EPA NSPS for sulfur dioxide emissions. Fortunately, the basis for determining sulfur dioxide removal is the Btu and total sulfur content of the run-of-mine coal. Thus, credit is given for any sulfur removed before combustion, e.g., through physical coal cleaning. Unfortunately, physical coal cleaning alone may be unable to produce a compliance coal with respect to the EPA NSPS. Therefore, all industrial and utility coal-fired boilers will require post combustion gas cleanup, e.g., flue gas desulfurization (FGD), to comply with the new regulations. Table 1 - EPA NSPS for SO2 Emission Category SO2 Content of ROM Coal SO2 Reduction Required 1 0-2 Ib/M Btu 70 2 2-6 Ib/M Btu To 0.6 Ib/M Btu (70% to 90%) 3 6-12 Ib/M Btu 90% 4 12 Ib/M Btu To 1.2 Ib/M Btu Alternatives to post combustion gas cleanup, such as staged combustion, lime and coal injection, fluidized-bed combustion, and chemical coal cleaning, are currently under development. Of these, chemical coal cleaning offers the advantages of providing (1) high quality fuel for combustion (low sulfur and ash, high Btu, and attenuated product variability); (2) a solid fuel product for use in retrofitted gas and oil boilers; and (3) a solid fuel product with multiple end uses, e.g., internal combustion engines, carbon electrodes, coke, or chemical feedstock. Gravimelt process In the Gravimelt process, 1.4 mm x 0 (14 mesh x 0), physically beneficiated coal of about 5% moisture is fed into a 3401 to 3901 C (644 ° to 734 ° F) molten bath of sodium hydroxide and potassium hydroxide. Organic and pyritic sulfur and most of the mineral matter in coal react with and are dissolved in a molten mixture of potassium hydroxide and sodium hydroxide. The reacted coal sulfur is converted to alkali sulfides and polysulfides, whereas the mineral matter is apparently converted to alkali-aluminum silicates and other byproducts that are water and acid soluble. Coal residence time is 60 to 240 minutes. The sodium hydroxide to potassium hydroxide ratio is about 9:1. The total hydroxide-to-coal ratio is no less than 10:1. The specific gravity of the caustic melt is about 1.8 g/cm3 . Thus, coal is buoyant in the bath, and insoluble mineral matter with density greater than 1.8 g/cm3 would sink. Reacted coal is first water-washed with an equal weight volume of water in a countercurrent mode of operation. The coal is filtered and the filtrate sent for regeneration. The coal is then acid-washed in 10% sulfuric acid. The acid-water/coal mixture is filtered to recover the final coal product, and the filtrate treated with lime to precipitate dissolved mineral matter. The precipitate is filtered from the mixture and discarded. The water is recycled to the plant. Filtrate from water-washing is treated to remove sodium sulfide. The sodium sulfide is chemically treated to produce hydrogen sulfide, calcium car¬bonate, sodium hydroxide, and other products. The hydrogen sulfide is treated to produce sulfuric acid for the acid-washing step. The calcium carbonate is treated further or discarded, and the sodium hydroxide is concentrated by evaporation and recycled to the reactor. The Gravimelt process is currently at the bench-scale stage of development. A 0.9-kg (2-lb) continuous reactor is in operation with a continuous water- and acid-washing section adjacent. The regeneration section is not developed to a meaningful extent, although key reactions have been tested in the laboratory. Process conditions, product recovery efficiencies, etc., however, have not been determined adequately and continuous regeneration operation has not been attempted. Work is now in progress to develop each section to a continuous bench-scale operation in processing coal at 9.1 kg/h (20 lb per hr). Microwave process The carbon and hydrogen in coal are relatively transparent to microwave radiation. However, water, caustic, pyrite, and other mineral matter components are strong conductors of microwave radiation energy at the proper frequency. As a result, selective heating of the noncarbonaceous materials occurs that enables the chemical reaction of sulfur and ash with caustic. Although very high temperatures may result from

Jan 1, 1987

By James Paone

Subsidence movements have damaged houses, schools, streets, and public utility lines in some undermined sections of Belleville and Maryville, Ill. In cooperation with local officials and the State of Illinois, the Interior Department's Bureau of Mines is sharing experience in backfilling abandoned coal mines to demonstrate that bituminous coal mine workings in south-western Illinois can be successfully backfilled and subsidence-prone areas stabilized. Subsurface investigations revealed that mine workings are dry and underlain by underclay deposits susceptible to instability upon wetting. Backfilling will therefore be accomplished by pneumatic injection instead of the hydraulic methods used in previous subsidence-control projects.

Jan 1, 1977

By J. W. Oberholzer

This paper describes research being undertaken by the Chamber of Mines Research Organization (COMRO) which is designed to assist the continuous miner operator and section foreman in the performance of their jobs. The project will initially provide visual assistance to the miner operator, and later will semi-automate the mining (cutting) process. Using a technique known as "RF tagging," the project will also provide real-time or near-real-time information about the performance of the loading and hauling units to the section foreman, allowing him to quickly detect problems and take action where appropriate. The project is based upon the application of currently available technology, and the first phase is scheduled for in-mine testing within the next year.

Jan 1, 1991

By John P. Mahaffey

Thank you Mr. Chairman, Ladies and Gentlemen of SME-AIM? for this opportunity to talk to you about, one of the most interesting and challenging facets of our mining industry. Because the need was then -we built in 1964 what is still today, one of the most sophisticated AC mining machine simulators for this or any industry. It simulated the electrical controls and circuits of an AC shuttle car. The student activated the controls on the main console, which represented the elementary control and power circuits. Its accompanying slide-tape program, student manual and worksheets provided our customers with an effective and highly motivational means to teach their face mechanics: 1. practical AC circuit and motor theory 2. print reading 3. troubleshooting techniques Nearly 10,000 men have put in over 100,000 manhours of training on the AC panel and its DC counterpart. The DC panel was modeled after the 14BU10 Loader. The success of these larger panels pointed out the need in our industry for an orangized, basic electrical program designed around mining machinery components & circuits. But probably more importantly, they brought to light the tremendous thirst for upgrading by our industry's employees. We then turned our attention to developing programs around very basic panels. The resulting programs were designed also to assure maximum student involvement.

Jan 1, 1975

By J. A. Procarione

Introduction Ventilation engineers have always felt somewhat uneasy when, in the normal course of their work, they are forced to consider the flow in any mine entry as "wholly rough." Under such conditions in pipes, friction factor is no longer a function of Reynolds' number. This assumption serves to simplify the problem and overcome an evident lack of information concerning the variability of K-factors. During the summer of 1985, a unique opportunity to investigate the reaction of friction factor to changing flow rates presented itself. A Utah coal mine was temporarily directing a substantial airflow through a single entry. By regulating the quantity, it would be possible to obtain a wide range of Reynolds' numbers in an entry composed of two distinct coal thicknesses. This paper describes the conducted study. The theory covering basic fluid flows in pipes that led to the questioning of constant K-factor is presented first. Experimental procedures are then described, including the use of a view camera in determining entry area and perimeter. Finally, a discussion of the observed variations in friction factor versus Reynolds' number is given. Changes of 34% and 45% in K-factor were seen in this study for the two entry heights. The implications of ignoring the relationship in this case and a call for an expanded research effort are also presented. Theory Since a gas is a fluid, the general principles of fluid mechanics are equally applicable to airflow in a mine entry as they are to the flow of water in a pipe. The Darcy equation is, therefore, equally applicable to pressure drop calculations in both situations. This famous formula was originally derived for use in circular cross sections and may be modified for any other shape by the use of hydraulic radius (defined as the area divided by the "wetted" perimeter). The Darcy equation relates the physical parameters of the pipe (diameter, length, and resistance to flow) and fluid velocity to the energy needed to create the flow. A study by Nikuradse (1933) brought to light the suspected dependency of the friction factor term in the Darcy equation upon Reynolds' number. By performing a large number of laboratory experiments, he established some basic concepts upon which other researchers built. Chief among these contributors was Colebrook (1939). Using commercial-grade pipe, he established an empirical relationship between Darcy's friction factor and Reynolds' number that is still in use today. If Colebrook's system of equations is plotted on log-log paper (as was done by Moody, 1944), the curves have some very distinct features. Of importance to the subject at hand is the relative response of friction factor to Reynolds' number at a given relative roughness. Simply stated, a pipe can appear to be either smooth or rough, depending on the flow conditions. As the Reynolds' number increases, the friction factor decreases at a decreasing rate until it becomes nearly a constant value. At this point, the flow is said to be "wholly rough." It is upon this condition that many traditional ventilation solution methods depend. For calculating pressure drops in a mine entry, Atkinson's equation is much more popular than the Darcy equation. Both of these formulas describe the same phenomenon and so have similar forms and functions. The K-factor in the Atkinson equation is equivalent to the Darcy friction factor and can be related by simply changing units, equating the pressure drops, and canceling like terms. A generalized form of this relationship is presented below as equation 1. K = yf/28,800g = [q]f/28,800 (1) where K is Atkinson's friction factor in kg/m3 (lb - min2/ft4), Y is the specific volume in Nt/m3 (lb per cu ft), p is the fluid density in kg/m3 (slugs per cu ft), g is the acceleration due to gravity (9.8 m/s2 or 32.2 fpsz), and f is Darcy's friction factor, which is unitless. The objective behind Eq. 1 is to show the strong correlation between K and f. Since these two quantities differ only by a constant (q]/28,000), the assumed independence of K-factor and Reynolds' number is suspect in light of the known response of f. Unfortunately, the formulation does not provide information concerning the actual relationship, as entry geometry likely plays a major role in the response curve. Only an indirect indication that such a relationship might exist is provided. Previous work on this subject was performed by Thomas Falkie (1958). The study involved a laboratory model composed of sections of straight, steel duct and a range of Reynolds' numbers from 15,610 to 137,200. Results from this work show a variation in friction factor with Reynolds' number in much the same way as it was found to vary in pipes. Over the range of velocities examined, a decrease of approximately 38% in K-factor was observed. This previous experience provides additional incentives to investigate the phenomenon under field conditions. Past model studies done at the University of Utah by Ozukurt (1945), Biron (1944), and Greenhalgh (1942) present similar evidence of this variability. More recently, Kharkar's (1974) study of coal mine friction factors contains similar indications that K-factor is not constant in all situations. Taken together, the data

Jan 1, 1988

By W. J. Miles

Diatomaceous earth or diatomite is a sedimentary rock of organic origin that is composed principally of the silicious skeletal remains of diatoms. Diatoms are microscopic single cell acquatic plants that are related to algae. Diatoms first became abundant in the Cretaceous period from about 65 to 135 million years ago. Most of the commercial deposits are of Pliocene through recent age, and are younger than 35 million years. Diatoms are still abundant in present day lakes and seas. The living diatom is supported and protected by two half cell walls or valves united by a connecting band or girdle. These valves are composed of opaline silica extracted from the water in which the diatom lives. After death of the diatom, the silicious remains settle in the lake or sea and accumulate at variable rates approaching several millimeters per year for very active diatom colonies. This accumulation of silicious sediments, after decay of the organism, burial, and uplift, can result in the formation of diatomaceous earth deposits.

Jan 1, 1987

By J. M. Keane

SMEThis loaner is concerned with important criteria relative to the design of small flota¬tion concentrators. For the purpose of this discussion a small flotation concentrator is defined as a facility having a designed ore feed rate of 1,000 metric tons per day (MTPD), or less. The decision to design and construct a small flotation concentrator is the culmination of a series of logical steps relative to the ex¬ploitation of a potential ore body. The information required for a rational and timely decision regarding plant design and construction is usually contained in a feasibility report. The information required in a thorough feasibility report has been summarized (1) (2) as follows: Type of mine or plant and proposed daily, monthly, and yearly production of all intermediate and final products. Quantity of indicated ore reserves. Location of project illustrated by a map showing surroundings, trans-portation facilities, and existing utilities.

Jan 1, 1980

By V. O. Tenorio, K. P. Hague

Mines are constantly trying to improve production processes by optimizing work cycles, reducing operational delays, minimizing costs, controlling equipment utilization, and preventing occupational hazards. Currently, advances in digital mining technologies within the concepts of 5G and Industrial Touch Internet are allowing better control and monitoring of underground mining equipment, with centralized control systems that unify data analysis for proper decision making. A wireless 5G-based platform for controlling and monitoring systems for underground mine operations can be designed over a comprehensive layout in where bandwidth selection, sensor location, Wi-Fi repeaters and power distribution are put together to build a successful supervisory system. In order to confirm the validation of these concepts, a case study is proposed for a medium-sized underground mine with a multi-level network which includes tablets managed by production supervisors, along with other data collection devices installed in semi-autonomous mining equipment, collecting, and distributing data in near-real time, with interconnection to support and services areas on the surface.

Mar 2, 2022

By S. Mathur

Polyacrylic acid (P AA) was evaluated as a selective flocculant for dolomite-apatite system. P AA of 4 million MW was found to flocculate both dolomite and apatite. However, their flocculation behavior was significantly different with 450,000 MW PAA which was the lowest molecular weight fraction capable of flocculation. In single mineral tests, at a dosage of 2kg/t 90% of dolomite and 35% of apatite flocculated. Selectivity was achieved in mixed mineral tests where apatite of 90% grade at 70% recovery level was obtained in the concentrate from a feed consisting of 80:20 mixture of apatite and dolomite. The dolomite rejection was about 75% which corresponds to 1% MgO in the concentrate.

Jan 1, 1995

By James J. Komadina

INTRODUCTION Newmont Gold Company's Rain operations are located in Elko County, Nevada, approximately 9 miles southeast of the Town of Carlin.The property was submitted to Newmont Exploration Limited in 1979 and underwent development drilling over the course of the next four years, culminating in the completion of a project feasibility study in October 1986. Initial project scope included development of an open pit mine, an 815,000 DSTPY heap leach, a 572,000 DSTPY mill (Mill No. 3), and associated support facilities. Approval to proceed was given by Newmont Gold Company management in June 1987. Detailed engineering began in early July, followed immediately thereafter by procurement of major equipment components through various second hand sources. PROJECT DESIGN Keep It Simple In early August, Newmont Mining Corporation, parent company of Newmont Gold Company, became the takeover target of an "investor" group headed by T. Boone Pickens. Details of the ensuing events have been well documented by the press; suffice to say their impact on this project was material and required immediate flowsheet changes. Project design throughputs were increased to 1,000,000 DSTPY and 760,000 DSTPY for the heap leach and mill, respectively, in mid- September. These changes caused major project headaches as all general arrangement drawings had been approved and structural steel as well as concrete contracts were in place. Additionally, ground breaking was to commence in two weeks time! Rain project management assembled shortly after the announced changes, to devise an engineering and construction strategy capable of handling these new business conditions. The project had been justified using a gold price of $325 per ounce with a forecasted overall cash cost per ounce of $230. Hence, strict control of capital expenditures was necessary to maintain development economics. Mill start-up had also been moved forward one month, to August 1, 1988. To meet an already ambitious schedule, construction techniques needed to be simple and proven as most of the facilities were planned for erection during winter at a site with design criteria of -40F and 90 mile per hour winds. Perhaps the most critical factor requiring consideration was that of personnel. Newmont Gold's revised business plan called for corporate-wide production increases from 587,000 ounces per year in 1987, to 1,400,000 ounces by mid- 1989. Labor requirements were forecasted to grow from 900 employees to over 2,100. This fact, in combination with the rapid growth of Nevada's gold industry, led to the expectation that turnover of operating personnel would be extremely high. It was concluded that, to meet cost, time, and operational goals, the necessary strategy could be succinctly put - "Keep It Simple." Mining/Metallurgical Factors The Rain deposit consists of three interconnecting mineable shapes with host rocks ranging from 90%+ barite to a highly silicified jasperoid. Due to a limited number of mining faces in the first two years, in-pit blending

Jan 1, 1990

By V. M. Lepetic

Large tonnages of copper and molybdenum sulfide ore are treated by flotation. Substantial savings could be realized, particularly in high-capacity concentrators, by use of a simplified flotation technique involving lower reagent consumption. Chalcopyrite and molybdenite from some deposits can be floated by use of only a frother as a single flotation reagent; acceptable concentrate grade and recovery can be obtained. Separation of molybdenite from copper sulfides may become simpler and less costly. The genesis of the ore and the ions present in the flotation pulp liquid phase appear to be the major success-determining factors.

Jan 1, 1972

By Patrick Shea

Old mine workings are found throughout the Western United Sates on lands administered by the U.S. Bureau of Land Management, U.S. Forest Service and private lands. Some of these mine workings date back to the late 1800s. There may be as many as 100,000 sites on lands administered by the National Park Service, U.S. Forest Service and Bureau of Land Management. The U.S. Department of the Interior has worked with the U.S. Geological Survey, the U.S. Forest Service, the U.S. Environmental Protection Agency, and western state governments to identify and prioritize these sites on Bureau of Land Management, National Park Service and U.S. Forest Service administered lands. This presentation will discuss the accomplishments we have made to date to clean up inactive and abandoned mine sites, focusing primarily on lands administered by the Bureau of Land Management.

Jan 1, 2000