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By D. A. Gulley, L. J. MacDonnell, William A. Vogely

INTRODUCTION Environmental impacts are most commonly associated with air and water pollution. Not- withstanding this fact, to many people the primary disruption caused by mineral extraction is the change in the character of the locale. That is, the environmental impact of mining includes, but is not limited to, the generation of residuals. The dramatic transformation of wilderness or rural land often creates strong reactions to mineral development. Thus, the basic issues of land use management are a useful addition to environmental discussion. In this section, we take up a discussion of federal, state, and local land use management regimes, along with a brief introduction to the potential role of economic analysis. Elsewhere in this volume, land management issues are discussed from other orientations, and the interested reader may wish to look there as well. Locatable Minerals on Federal Lands Legislation and Administration: Access to hard-rock minerals on the public lands is governed by the General Mining Law of 1872. This law declares that "valuable mineral deposits in land belonging to the United States . . . are hereby declared to be free and open to exploration and purchase . . . ." In order to initiate rights, prospectors are required to physically stake claims of specified sizes and shapes following basic procedures set by federal law which may be supplemented by the individual states. Rights to these claims are protected at the exploration stage so long as actual possession is maintained and diligent exploration activity is underway. If a valuable mineral deposit is discovered on the claim, the claimholder earns the exclusive right of possession as against private parties so long as the claim is properly maintained. To maintain this exclusive right the claimholder must per- form $100 worth of labor or improvements, known as assessment work, on each claim every year and make related annual filings with the U. S. Department of the Interior. If the existence of a valuable mineral deposit can be demonstrated, and other legal requirements are met, the claimholder may receive a patent giving full title to the claimed land, including the surface in most cases. The purchase price is either $2.50 or $5 .OO per acre. The Mining Law has remained largely un- changed by legislative amendment during its now more than 100-vear existence. However, while the law itself has not changed, its interpretation and administration have changed considerably. Written at a time of rapid western expansion of the U.S. following the Civil War, the intent of the law was to promote mineral development by inviting unrestricted prospecting and by selling the lands containing mineral deposits at a minimal charge. As federal land policy shifted from one of rapid disposal into private ownership to one of retention and management for a number of uses, mineral patenting requirements have been administered more strictly. The most critical issue concerns what must be demonstrated to establish the existence of a valuable mineral deposit. The so-called "prudent man" standard was established in the case of Castle v. Womble (19 L.D. 455 (1894)):

Jan 1, 1985

By J. D. Miller

On the basis of nonequilibrium zeta potential measurements by laser-Doppler electrophoresis, the sign of the surface charge of alkali halides in their saturated brines has been established. The results are generally as expected from simplified lattice ion hydration theory. This recent electrokinetic information coupled with the stability and prevalence of collector colloids in such soluble-salt flotation systems suggests that the selective flotation of alkali halides is due to the adsorption of oppositely charged collector colloids by heterocoagulation. Experimental flotation results confirm this surface-charge/collector-colloid adsorption model and are presented herein.

Jan 1, 1992

By Richard B. Berg

Chlorite veins in the Silver Star district (40 km southeast of Butte) were of little interest to those who were mining gold and silver in the late 19th century. It wasn't until 1975 that unusually pure magnesian chlorite of the variety clinochlore was identified from a ?talc? claim in this district. In 1977 tests by Cyprus Industrial Minerals showed that this chlorite was suitable for use in ceramics. Mining begun in that year continues. These replacement veins of chlorite in Precambrian quartzofeldspathic gneiss differ from the metalliferous veins to the northwest in both attitude and mineralogy.

Jan 1, 1982

By James L. Hendrix

This paper is intended to give the reader an update on the work being done at the Mackay School of Mines about the fate of cyanide on precious metals mill tailings waste. During the last two years several tailings impoundments have been sampled and analyzed for total and free cyanides. From our sampling program we are beginning to learn valuable information concerning the fate of cyanides in precious metals mill wastes. Included in this paper is a detailed description of our sampling and analytical techniques. Also, some of the data obtained from five sites are given.

Jan 1, 1986

By M. D. Chatham

Revolutionary electronic monitoring and control systems provide a gold mine of diagnostic and prognostic information. Lower cost per ton results from timely operator action, increased visibility of information to production and maintenance personnel, and better fleet management. When information is effectively integrated into fleet management systems lower costs result from higher availability, longer component life and reduced repair cost. This paper will present the objectives of the Caterpillar Vital Information Management System (VIMS) and provide actual examples of successful use.

Jan 1, 1995

By R. J. Good

It is well known that the elimination of impurities such as iron pyrite, shale, clay, silica, etc., from coal, by floatation [Sun, 1954; Aplan, 1983] and selective oil agglomeration [Keller and Burry; 1990] depends on the fact that coal is hydrophobic, and the impurities are hydrophilic. The water contact angle has long been used to evaluate the hydrophobic nature of coal, first by Brady and Gauger (1940), who demonstrated that the contact angle of water on coals increases with rank, and passes through a maximum at about 88% carbon. Brown (1962) found that the contact angle of coal decreased with increasing ash content. Sun, and also Aplan, have reported a direct relationship between values of the contact angle and rank, and have related the contact angle to coal floatability. Horsley and Smith (1951) first demonstrated that the captive bubble contact angle may be used to characterize the hydrophobicity of a coal containing more than 80% carbon DAF, while Parekh and Aplan (1978) have shown that the sessile-drop technique may be used to evaluate the hydrophobicity of coal of any rank.

Jan 1, 1992

By D. Goffaux

In less than two years, Stratmin has discovered, explored, developed, financed and put into production by open pit, a large graphite mine. The deposit, hinted by airborne electromagnetic survey, was discovered in September 1987 through various ground geophysical surveys, diamond drilling and trenching. The open pit started production in February 1989, feeding a nearby leased mill at Notre-Dame-du-Laus (Quebec), having a processing capacity of 400 tons per day. A new 1,000 tonne per day mill was built at the mine site, in Lac-des-lies (Quebec) and began production in April 1990. The Lac-des-lies graphite operation is currently one of the largest of its kind in the world. Mine and mill facilities are operated by Stratmin Graphite, jointly owned by Stratmin Inc. (75%) and Imetal-France (25%), a wholly owned subsidiary of Imetal (France). From initial exports limited to Japan and United States, Stratmin Graphite is now exporting in fourteen different countries, attesting to the very high quality of its products, with grades ranging from 92% to 97% carbon. Among the numerous graphite deposits discovered in Canada, Stratmin Graphite Inc. has emerged as the leader and virtually the sole crystalline graphite producer in North America, operating on a continuous basis.

Jan 1, 1992

By P. Oghazi

It is possible to have traceability in the mining industry, by parameters and signatures like particle mineralogy, mineral association, texture and mineral liberation. The study is on an apatite-iron ore deposit at Malmberget, Sweden, and characterizes an ore body both mineralogically and texturally in a quantitative manner by using analytical methods like optical microscopy, microprobe (EMPA) and an automatic SEM based system, Particle Texture Analysis (PTA). The mineralogy was evaluated by PTA and characterized by modal mineralogy, mineral liberation and mineral associations. Magnetite has a simple outline and straight grain boundaries and the gangue minerals have a finer particle size with a more complicated texture. The PTA analysis also shows that apatite is associated to magnetite as mixed particles, while smaller grains of magnetite are inclusions in feldspar. Result from particle texture analysis shows that there is a connection which link to the mine-to-mill context, and it may be used to create traceability. This link is not the associations of the main ore mineral magnetite, nor the modal mineralogy. Instead, it is the mineral associations of contaminating minerals (apatite and feldspar) that appear to be most promising since they survive from mine to mill. The modal mineralogy may be used to understand how contaminated minerals break into or out of particles size fraction during grinding.

Jan 1, 2010

By and Heather E. Lawson, Mark K. Larson, Gabriel Walton

In this study, we evaluated the effects of different shapes and distribution densities of mineral grains in coal on failure mechanics using the numerical software 3DEC. The main aim of this study was to identify possible failure mechanisms influenced by mineral habit and frequency in coal. Exploring differences in failure mechanics associated with the mineral grains helped to determine the role of mineral character as a possible contributor to characterize burst-prone coals. To achieve the goal of this study, a series of numerical specimens were prepared in the 3DEC model as follows: first, the 3DEC modeling in conjunction with the DFNs (Discrete Fracture Networks) technique was performed to explicitly generate the discontinuities (i.e., cleats and bedding planes) in the numerical specimens based on the results of laboratory analyses. Then, the different realizations of mineral grains were embedded in the 3DEC model to simulate an unconfined compressive strength (UCS) test to assess the influence of the mineralogical characteristics on the UCS.

By F. G. Loper

Simulation as a mathematical technique is not new. However, recent increases in digital computer speeds and the ease of programming with languages such as Fortran have centered a good deal of attention around simulation in the last few years, Many sophistications of the method have been developed during this time. However, the ability to simulate mathematically still hinges on the ability to ignore unimportant details which would complicate the mathematics and make simulation impractical, Thus, with this attitude in mind, it becomes very easy to design a pseudo- simulator which will predict average conditions very well, but can not truly allow a detailed study of the system being simulated. Most simulations fall into this category, along with the case mentioned here. This paper is not intended to be a critical treatise of the simulator used to study a particular mining system. Instead, it will be used to illustrate the aspects of simulator development. The steps in the development of any simulator are described, along with same detail of the phosphate mine simulator itself.

Jan 1, 1966

By Ashish Ranjan Kumar, Barbara Arnold, Luis Sanchez Gonzalez

Mining operations adopt a variety of measures to combat dust underground. These include ventilation systems, water sprays, physical barriers, and personal protective equipment (PPE). Respirators are a class of PPE that can provide clean particulate- free air to the users. Powered Air-Purifying Respirators (PAPRs), used commonly in medical and other sectors, are not prevalent in the mining industry. PAPRs use P100 filters that have 99.97% dust capture efficiency. We present our results from computational fluid dynamics (CFD) simulations performed to understand the impact of a PAPR on airflow and dust particle concentration in the vicinity of a miner. These results show that donning PAPRs can lower the miners’ exposure to respirable coal dust in their workplace.

Feb 1, 2025

By Liming Yuan, A. C. Smith

Barometric pressure changes affect air density, leading to change in the mass of the gas in the gob. When the barometric pressure decreases, the volume of gas in the gob expands, while the volume of gas contracts when the barometric pressure increases, a process which causes the gob to “breathe” out and in. Although the concept of gob “breathing” is simple, its effect on spontaneous heating of coal in the gob area is not clear. In this study, computational fluid dynamic (CFD) simulations were conducted to model the spontaneous heating of coal in the longwall gob area under measured barometric pressure changes. A single longwall panel using a bleederless ventilation system was simulated. If there is no barometric pressure change, the intake airflow rate is equal to the return airflow rate. When the barometric pressure changes, these two airflow rates are no longer equal, and the difference between the two airflow rates represents the airflow rate the gob breathes in and out. The effect of inflow and outflow of gas on the potential spontaneous heating in the gob was investigated using the CFD model developed in our previous study. The effect of barometric pressure changes on the spontaneous heating was found to be dependent on the gob permeability and the coal oxidation rate. The effect of barometric pressure changes on oxygen concentrations in the gob was also examined.

Jan 1, 2010

By K. K. Bhattacharyya

In the Gulf Coast area lignite deposits occur in Texas, Louisiana, Arkansas, Mississippi and Alabama. Lignite has been mined in Texas since the early 1800's reaching a production of over 900,000 metric tons (1 million short tons) in 1910. With the availability of inexpensive oil and gas, production fall to as low as 16,000 metric tons (18,000 short tons) by 1950 (Henry, 1976). With the advent of the oil and gas shortage in early 1970, lignite production began to increase again. The purpose of this paper is to discuss the geotechnical considerations of mining lignite in the Gulf Coast area, particularly Texas and Louisiana. Lignite deposition occurs in unconsolidated sand, silt and clay environments. Extensive sand units saturated with water may be present within the potential mining depths. This paper describes the geotechnical considerations for designing a surface mine in this geographical area. These factors include geology, hydrology, mining method, and equipment utilization.

Jan 1, 1982

By R. M. Yeates

Public concern over possible degradation of groundwater resources has resulted in an array of Federal laws and corresponding state laws to regulate contaminates from solid and hazardous waste. A mine owner must be familiar with environmental regulations which could impact his operation and must know what precautions and corrective actions to take in order to protect his mining operation from potentially expensive remedial actions. The Environmental Protection Agency (EPA), has issued few regulations controlling the management of mining wastes. Federal regulation of mining came primarily under the Surface Mining Control and Reclamation Act (SMCRA) administered by the Office of Surface Mining (OSM). Waste generated from the extraction, benefication and processing of ores and minerals was exempt from regulation under the Resource Conservation and Recovery Act (RCRA), which is EPA's major instrument in controlling surface contaminates. On December 31, 1985, EPA submitted to Congress a report entitled "Wastes from the Extraction and Benefication of Metallic Ores, Phosphate Rock, Asbestos, Overburden from Uranium Mining and Oil Shale", which will be referred to, henceforth, as the Congressional Report. This Congressional Report assessed the possible adverse effects of mine associated wastes. This report is the first step toward developing regulations with which EPA can regulate waste from the extraction, benefication and process of mineral ores.

Jan 1, 1987

By C. Bateman, F. Calizaya

"This study presents the results of three laboratory experiments on pressure balancing carried out at the University of Utah’s coal mine ventilation model. The model includes simulations of two working areas, one longwall mine gob, and a set of stoppings and seals. It also includes a pressure chamber between the longwall face and the gob. The model is ventilated by one main fan and one bleeder fan. A carbon dioxide injection system, equipped with flow control valves operated by a microprocessor, is used to pressurize the chamber and to maintain the pressure in the chamber slightly higher than that of the gob. During each experiment, fan pressures and stopping resistances were changed, the carbon dioxide injection rate was regulated, and the differential pressures across the stoppings were monitored so that the chamber pressure is always kept slightly higher than that the gob pressure. Result of these experiments are reported in this paper. INTRODUCTION Spontaneous combustion (Sponcom) is a safety hazard in underground coal mines. The history of coal mining in the US is replete with mine fires and explosions. Sponcpm accounts for approximately 17% of the total number of fires recorded in the U.S. since 1990. In the U.S., by law, worked out areas in coal mines must be either ventilated by a bleeder system or isolated by explosion proof seals. Experience has shown that seals are not airtight structures and that they allow some leakage of air into or out of the gob. In fact, seals “breathe in and breathe out” with changes in barometric pressure (Francart 1997, and Chalmers 2010). These changes in pressure affect not only the methane emission rate but also the ingress of oxygen to the gob, the lower the pressure behind seals is, the higher the ingress of oxygen. In mines ventilated by a U-tube exhaust system, the gob is often kept under negative pressure. Under these circumstances, an increase in barometric pressure may cause an influx of fresh air into the gob. This quantity may be sufficient to start self-heating of the coal, which can lead to spontaneous combustion. Depending on the coal characteristics and the ventilation conditions, self-heating of coal can start at temperatures as low as 35 ºC. If the heat is not removed it will increase the coal temperature leading to ignition and fire. The risk of Sponcom fires can be reduced by isolating the mine gob using rated seals, and implementing a suitable ventilation system. However, isolation seals are not airtight structures, thus some leakage of air is expected unless the pressure in the gob is neutralized. The alternative is to use a pressure balancing system. This requires a thorough knowledge of the ventilation system, the seal/stopping construction techniques, the airflow behavior in the gob area, and the gas build-up behind the seal line."

Jan 1, 2016

By O. M. S. Rodrigues

The kaolinite presence in bauxite ores increases caustic soda consumption during the digestion step in the Bayer process. Depending on the kaolinite content, the utilization of the ore in the Bayer process may be unfeasible. This investigation addressed the variables involved in kaolinite flotation through microflotation experiments in a Hallimond tube and zeta potential determinations. The tests were performed with a pure sample of kaolinite (96%). Five collectors were tested: Duomeen T (DT), cetyl pyridinium chloride (CPC), cetyltrimethylammonium bromide (CTAB), dodecylamine (DDA) and Flotigam EDA (EDA). Four of them performed well as collectors, at a concentration of 1x10-4 mol/L: CPC, CTAB, DDA and EDA. The kaolinite isoelectric point (IEP) was determined at pH = 4.6. The IEP was shifted towards higher pH values in the collectors? presence, indicating specific adsorption onto the mineral surface.

Jan 1, 2011

By J. R. Maxwell

The development, commercial installation, and operating performance of large capacity Maxwell Flotation Cells. Volumes ranging from 300 cubic feet to 2,000 cubic feet per flotation mechanism.

Jan 1, 1971

By B. E. Davis

A fundamental study of the mechanisms involved in the conditioning of coarse Florida phosphate has led to some interesting discoveries. Studies by the Bureau of Mines have shown that conditioning time and mixing intensity greatly affect the grades and recoveries of the phosphate minerals and quartz in the rougher concentrate. In particular, as the conditioning time or mixing intensity increased, the phosphate recovery remained constant while the amount of quartz floated decreased. This phenomenon is contrary to conventional wisdom and could lead to a more efficient coarse flotation circuit.

Jan 1, 1993

By F. B. Olender

Idler engineering, operation, and maintenance cannot be covered in depth in a short paper. Therefore, this will be a general look into the subject matter in light or the present-day technology. Depending on the source or reference used, belts for handling bulk material underground came into being between 1900 and 1920, while strip mining appeared in the thirties. The conveyor belt speeds in that era were in the 300 rpm to 500 rpm range. Belt speeds or 600-700 rpm were in vogue in the thirties, and the early sixties saw speeds or 800-900 rpm. Today, speeds or 1000 rpm are not looked at with dismay; in fact, speeds or 2000 rpm are being discussed. Among the driving forces moving the bulk materials handling industry to these greater heights have been the mining operators and engineers. Their appetite to increase output, yield, and reduced per-ton costs has constantly challenged the bulk material handling industry to develop products capable or handling these increased capacities. One or the products affected by this movement is the idler. Apart from the conveyor belt itself, it is one or the most significant parts or a conveyor system because or the sheer numbers needed in an installation.

Jan 1, 1971

By K. E. Robinson

During operation of tailings impoundments, water is lost through decanting, evaporation and seepage. Techniques have been developed to regulate or control each of these components. Collectively implemented, these techniques form the basis of tailings impoundment management. Regulation of the rate and level of decanting influences the size of a free water pond, and, thereby, the amount of evaporation and seepage, which are both area-dependent. Conversely, the encouragement of seepage and/or evaporation could also be used to reduce decanting requirements. Management of one of the components of a tailings impoundment's water balance is reflected in changes in the other components. The seepage component has the greatest potential impact on the environment, and consequently requires the closest scrutiny. Water percolating through tailings backfill transports heavy metals and other dissolved solids from the impoundment into the local groundwater regime. Depending on the seepage volume and concentration of contaminants, seepage from impoundments could exceed environmentally tolerable limits. Once mobilized, seepage-borne pollution is much more difficult to treat, mainly because of the problems in collecting the diffusive transportation medium. Pollution abatement measures relative to tailings impoundment seepage depend on seepage prevention or reduction. Seepage control measures include constructing barriers to flow, pump-back systems of interception and restricting the supply of water available for seepage.

Jan 1, 1987