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By A. D. Davis

The Bear Butte Creek watershed, in the northern Black Hills of South Dakota, shows the effects of past mining activities in the form of dissolved metals and arsenic in stream water. Bear Butte Creek, during normal flow periods, loses all of its discharge to sinkholes that recharge the Madison Limestone aquifer. This work focused on the geochemical transport and fate of arsenic and on understanding ground-water flow conditions in the Madison aquifer through development of a three-dimensional ground-water flow model that was coupled to a geographic information system (GIS). Stream sampling and discharge measurements helped determine sinkhole losses and loading rates. Column laboratory tests provided data on arsenic adsorption and the mixing of stream water with aquifer water, which also was simulated with the geochemical models, pHREEQE and NETPATH. The models and GIS can be updated with new information and will be useful in managing the water quality of the Madison aquifer.

Jan 1, 1997

By Robert A. Jankowski, Fred N. Kissell

Recent allegations about tampering of coal mine dust samples have led to suggestions that the coal industry needs a respirable dust compliance sampling method that is less subject to tampering. The sampler designs under consideration include fixed location monitors that could be mounted on a mining machine or located at a stationary location in the mine, and samplers that are worn, like the existing samplers. Fixed-point samplers have a design advantage, since samplers worn on the body will have size and weight limitations. On the other hand, in some cases there are respirable dust concentration gradients, which will dictate careful placement of a fixed-point sampler inlet to determine the exposure of workers. This study examined dust concentration-gradient data obtained by the Bureau of Mines and others over the last decade. As an example of spatial gradients at continuous miners, a fixed-point monitor located in front of the operators cab shows a higher dust concentration than a sampler located on the operator and reduced exposure when the sampling location is behind the operator cab. It may be necessary to use a sampling tube with a machine mounted monitor, to sample in the operators breathing zone in the cab to provide a more representative sample of the miners exposure. For face workers on longwalls or on continuous miner sections using remote control, the study shows significant dust level gradients and gradient variations between typical operator positions and mining machine locations. In addition, if fixed-point monitoring is used to monitor an area, vs the exposure of specific workers, dust control technologies currently employed to ensure reduced dust exposure such as the diversion of dust laden air away from the workers, or through the use of remote control of mining machinery may not indicate the same dust reduction obtained with current sampling techniques.

Jan 1, 1993

By Ritika Kundu, Moussa Wone, Amanda M. Morgan, Tatiana K. Proctor

The Piney Branch CSO 049 Storage Tunnel (PBST) will be the last major project for the DC Clean Rivers Program. The project includes construction of a 2,200-foot-long, 18-foot-internal-diameter storage tunnel; two connections to combined sewer infrastructure; and two shafts. Major challenges include excavation underneath an existing live outfall that must remain in service; excavation of the tunnel through several areas of low rock cover and mixed-face conditions; and negotiations with a variety of federal, regional, and local stakeholders to address project impacts. This paper describes the overall project scope; geotechnical conditions along the alignment; design and construction challenges; and construction procurement.

Jun 23, 2024

By R. Sellaro

It has long been understood that extended occupational exposures to respirable mine dusts can lead to chronic lung disease. In underground coal mines, CWP and silicosis are major concerns. While there have been many studies aimed at understanding total dust concentrations and silica content associated with different mining conditions (e.g., locations/occupations within a mine, cutting methods, geologic strata), little research has been completed to more comprehensively characterize respirable dust (i.e., by particle composition, size distributions, shapes). This preliminary study sought to characterize dust from an underground coal mine in Central Appalachia using scanning electron microscopy with energy dispersive x-ray (SEM-EDX). Respirable dust samples were collected from various locations in the study mine, and individual dust particles were identified and classified by mineral type. A continuous personal dust monitor was also used to estimate total respirable dust concentrations during sampling. Here we report initial results of this work, and discuss advantages and challenges of particle-level characterization of mine dusts in terms of occupational health research.

Feb 23, 2014

By F. Mielli

Over the last three years there has been an increase in mining congress and conferences focusing on water management. Water in mining is a key concern for mine managers and operations, and we are now seeing this operational dilemma escalated to the level it deserves. According to Frost & Sullivan research, mining water and wastewater treatment and its related technologies will be a U$3.6 Billion global market in 2016, which translates the importance of this issue. Looking at the current mining trends, some factors increased the importance of water in mining operations, including: ? Future mining investments will be located in geographical locations where water is scarce (water stressed areas) ? A decline in grade will increase the intensity of mineral processes and therefore increase the use of the water ? Increased sustainability and regulations will extend the control/monitoring of water during the entire mine life cycle representation of the mine water flow system. A water balance has several benefits/objectives in a mine operation: ? Mine planning/simulation of mining scenarios/climate change Production optimization ? Minimizing strategic and operational risks ? Social license to operate ? Water-smart mine planning ? Target: water neutral mines ? Benchmarking within and between sites ? Sharing knowledge/technology transfer ? Reporting/communications ? Permitting/Compliance

Feb 23, 2014

By Robert L. Russell

The Bunker Hill Mine, located in the Coeur d'Alene Mining District at Kellogg, Idaho, has been a major producer of lead-silver-zinc ores since its discovery in 1887. The mine has produced over 29 million tons of ore from some 20 to 25 veins and ore zones, and now covers an area approximately one mile in length and one-half mile in width. The active section of the mine extends from 2500 ft above sea level to 1600 ft below sea level. Production is presently at the rate of about 1700 tons of ore per day. A two-mile adit, the Kellogg Tunnel, at the 2500 elevation, provides access to the main shaft area. Ore is hoisted to the adit level through a 5000-ft, 500-inclined shaft, extending to the lowermost haulage level 1200 ft below sea level. Primary shaft service for men and materials is supplied by three major internal, inclined shafts equipped with double-drum hoists. Present production requires ten levels to serve for mainline track haulage. These range up to 5000 ft in length and are either 200 or 400 vertical feet apart. Also, many intermediate levels exist throughout the mine. The conventional and autoloader mechanized square-set and cut-and-fill mining methods used throughout the mine have been the subject of a recent paper(l). One-third of current production is from vein-type ore bodies which are long distances from main shaft areas. Such veins generally dip about 450, have relatively narrow widths of from 3 to 20 ft, and usually contain less than 500,000 tons of ore. For many years, ore bodies thus situated have been developed by means of a separate inclined, timbered service shaft-raise connecting two or more main haulage levels. These commonly range from 400 to 1000 ft in vertical extent and are equipped with 25 to 50 hp electric, single-drum hoists. Intermediate levels are driven as conventional track drifts at 100-ft vertical intervals between the haulage levels. Ore and waste from the intermediate levels are trammed to orepasses for delivery to the lowermost haulage level servicing an ore body. The final result may be visualized as a number of small mines within a large mine. The problems of high development costs and high total development time, and the large amount and high cost of providing materials handl ing and ore haulage service while producing from this isolated type of stope block, made it desirable to consider totally new approaches in developing and mining a number of similar areas.

Jan 1, 1971

By M. McPherson, G. Danko

Methods of measuring in situ rock thermo-physical properties are rapidly evolving. Among those existing in the literature, a particular measurement procedure was selected for further development. The measurement is based on creating a spherical temperature field in a drill hole using a point source heater of constant heat flux. The bivariate temperature distribution 0 (r, t) is measured at several points along the length of the drillhole, radius r from the heater and at particular time intervals (t). A number of different evaluation methods were tested for calculating the unknown thermal conductivity (k) and diffusivity [] from the measured temperature and the known heat flux. The results showed that evaluation using the finite difference scheme and small temperature differences measured at points close together, cannot give a reasonable result. In order to solve the problem a new general analytical evaluation method is developed. Using an appropriate technique, it is possible to simultaneously obtain values for k and [], incorporating a semi least square technique to reduce the uncertainty in the evaluation. The new device and evaluation method makes it possible to obtain from a single drill hole highly precise k and [] values within an 8 hour period. The method has been used in several underground mines in the U.S. with good results.

Jan 1, 1987

By Geoffrey G. Hunkin

This is a brief state of the art paper describing current (1975) Uranium recovery plant flowsheets, some notes on system selection, design philosophies, and materials of construction. The in-situ, or borehole solution mining, of Uranium is a process which has been developed over recent years to better match Uranium mining and milling technology with the size, shape, grade and territorial distribution of the remaining identified Uranium deposits of western United States. Solution mining recovery plants are pure hydrometallurgical units ideally suited to automation, modular design, and mobility. Similar to conventional Uranium mills, two basic flowsheets, one acid and one carbonate, are in use, but the predominance is reversed so that the majority of plants employ the alkaline carbonate flowsheet, All plants incorporate resin bead ion exchange Uranium recovery for both acid and alkaline circuits.

Jan 1, 1976

By O. J. R. Baena, D. E. Chaverra, C. D. L. Ramirez

Cyanide is one of the most used reagents in the precious metal extraction process; as well as the most efficient from the point of view of the dissolution process; but it is also a toxic product that requires a lot of care in handling. Likewise, the residual solutions of the process must be followed because they can be a risk of contamination of water, animals and human health. In the artisanal processes of obtaining gold and silver, neutralization of the residual solutions is used to passivate the present cyanide. During this process ammonium cyanate is formed which decomposes rapidly in the presence of air and sunlight in carbon dioxide and ammonia gas, contributing to the greenhouse effect. In this work the use of the ammonium cyanate obtained in the process of neutralization of the cyanide solutions as a reagent to obtain urea is proposed. Urea was obtained indirectly through the use of the reagent kit UREA/BUN-COLOR. The process is effective at pH ≤ 4.5 with a rapid increase in solution temperature, and addition of hydrogen peroxide. The urea crystals begin to form at 50°C. The cyanide / urea ratio obtained was 1 / 7.5 INTRODUCTION In the processes of extractive gold metallurgy, the use of cyanide leaching is perhaps the most widely used method worldwide; by the ease of operation, its low cost and high levels of precious metal recovery. However, neutralization, in most processing plants, is not done properly, and leftovers of solution with free cyanide are dumped in concentrations harmful to the environment, in particular animals and humans. Cyanide can enter surface water through releases from industries using cyanides. Due to its high toxicity, the presence of cyanide in water is a matter of great concern (Jawale et al., 2017). The pollution generated by the effluents from the leaching of gold ores is one of the main obstacles of social opposition presented by mining activity due to the impact of both surface and groundwater. During the cyanide decomposition process, a compound known as ammonium cyanate OCN(NH4), which is a raw material for the manufacture of urea, CO(NH2)2 is generated. In the case of good neutralization, cyanide is no longer a toxic compound through oxidizing reagents, but as a result, there is the generation and emission of ammonia and carbon dioxide into the atmosphere, generating both a greenhouse effect (Gómez, 2012). This is evidenced by the strong effervescence of the reaction, and a penetrating smell of ammonia, which can irritate respiratory mucous membranes and eyes; however because they are greenhouse gases they are considered pollutants.

Jan 1, 2019

By David R. Delling

Tenneco is a large, diversified, energy-based company which has grown rapidly during its forty year life. We're the youngest corporation among Fortune's top 20 companies. Tenneco Minerals Company is the division of the Corporation responsible for nonfuel minerals exploration, development and operations. Tenneco Minerals Company is headquartered in Lakewood, Colorado. Exploration offices are in Colorado, Nevada, Alaska, and Perth, Australia. We currently operate two gold mines in Nevada and a large underground trona mine and soda ash processing plant in Wyoming. The latter has a capacity of 907 000 tonnes per year of soda ash and is the subject of my presentation today.

Jan 1, 1984

By L. R. Berry

The successful selection of a slurry pump depends on the accuracy and completeness of the information provided for the application. Inaccurate or incomplete information can result in incorrect pump selection and / or operational problems. Some information is more critical to the selection process than other information. A full description of the slurry (liquid -solid mixture) including the particle size distribution and maximum concentration, the flow, head and NPSH requirements are most important for successful slurry pump selection and operation. Common problems resulting from improper slurry pump selection will be discussed to illustrate the need for correct selection requirements.

Jan 1, 1996

By G. H. Roybal

Humic-acid-rich deposits exist in Arkansas, Florida, Louisiana, New York, North Dakota, Michigan, Minnesota, Texas, and Wyoming (Burdick, 1965) and in New Mexico (Shomaker and Hiss, 1974). New Mexico humic deposits are associated with coal in the northwestern part of the state where humate and weathered coal are presently mined. Discussion of the humic -acid industry in New Mexico requires an understanding of complex terminology and coal geology. TERMINOLOGY Humic material is not a pure substance so an ambiguous and complex terminology is in use by geologists, chemists, soil scientists, agronomists, and producers. Material mined for its humic-acid content is an extremely variable mixture of base-soluble humic, fulvic, and ulvic acids and their salts, formed during partial or complete decay of organic matter. This decay releases a high-molecular-weight organic material which is darkly colored, partly colloidal, and weakly acidic.

Jan 1, 1985

Stillwater Mining Company (SMC) has an extensive history with tunnel boring machines (TBM) at the Stillwater and East Boulder underground PGM mines in Montana. The most recent TBM used is for the Blitz Project, where a 5.5m (18ft) diameter main beam unit, commissioned in Q3 2012, is being utilized to drive a 6,975m (22,500 ft) ventilation and haulage level East of the Stillwater Mine for the Blitz expansion project. The assembly/commissioning of the TBM, institution of the planned diamond drilling program, application of ground control systems, and the current tunneling metrics will be covered.

Feb 23, 2014

By Ken J. Richards

Industries dependent on pyrometallurgical processing generally find themselves facing a common set of problems, namely, serious environmental restrictions, heavy capital requirements for new facilities and for plant modernization, the certainty of rapidly escalating fuel costs, and the uncertainty of fuel availability. To remain competitive, it has become clear to industry that a new dimension of attention must be given to assuring the maximum performance from plant facilities already in place and from those that are built in the future. In the last decade or so, in response to these needs, there has been an acceleration in the development of new pyrometallurgical process concepts. Their application, though spotty, is increasing. A common factor in this developing base of technology is the need for effective process control. Digital control is an indispensable element of meeting the challenge. We cannot make the point, however, by looking to a general survey of instrumental control of pyrometallurgical processes. Computer control is in its awkward adolescence. Its application is so new that only isolated applications can highlight the trends. For this reason, the authors have chosen to focus on the nonferrous smelting industry to illustrate the status of pyrometallurgical processing and control. We believe this approach will best meet the interests of most readers of this edition and the background of the authors.

Jan 1, 1979

By E. W. Geist, W. J. Bronkala

PRINCIPLES OF MAGNETIC SEPARATION The application of magnetic separators relies on the different behavior of individual mineral particles under the influence of magnetic forces. When exposed to a magnetic field, all materials are affected in some way. According to whether materials are attracted or repelled by the magnetic field, they are designated paramagnetic or diamagnetic, respectively. Paramagnetic materials are attracted along lines of magnetic force from points of lower magnetic field intensity to points of higher magnetic field intensity. The very strong response of some materials to a magnetic field is sometimes designated ferromagnetic and the particles attracted frequently retain magnetic properties after the applied magnetic field is removed. Diamagnetic materials are repelled along the lines of magnetic force from points of high magnetic intensity to points of lower field intensity. Only limited commercial use of diamagnetic effects has been made. For practical applications, the paramagnetic groupings are: 1. Strongly magnetic (ferromagnetic) 2. Magnetic 3. Weakly Magnetic 4. Non-magnetic The limits of these groupings are not well defined and will vary in some mineral species. Only a few minerals are ferromagnetic (magnetite is an example) and arbitrarily some investigators have selected 10,000 gauss, or 1 Telsa, as the dividing line between low and high intensity magnetic fields. I. S. Wells has developed a table indicating the magnetic intensity required to separate a selected grouping of minerals which is shown in Table 1 on page 2. A similar table has been developed by Carpco Inc. of Jacksonville, Florida in conjunction with the use of its high tension separators. This table, Table 2 on page 3 shows other minerals grouped in the broader categories cited above. Magnetic separation methods are used either to separate valuable minerals from nonmagnetic waste or magnetic impurities or other valuable magnetic minerals from bulk nonmagnetic values. Magnetically susceptible mineral particles occur as either individually discrete particles,

Jan 1, 1986

By R. D. Coursen

Tin has been one of the very few commodities which has been covered by an international commodity agreement. It is the only metal so covered. The reason behind tin's prediliction for an agreement has been the inconsistency of the price pattern for tin during the entire 20th century. It is not surprising in view - of the wide and wild fluctuations in its price that tin has been called the Cinderella metal. An examination, for example, of prices in 1977 alone attests to the erratic behavior of the tin markets. The high was recorded on October 27 at M$1,895 per picul and the low on January 3 at M$l,314 3/8, on the Penang market, a spread in Malaysian dollars of $581 for a picul weighing 133 1/3 pounds. The first steps in international cooperation on tin were taken after the price bonanza of the First World War. Despite a lack of increased consumption, and in spite of the fact there was no shortage of mining production during the war, prices boomed. Shipping shortages and thinning stocks brought about a situation where in the U.S., industrial stocks were only 1/6 of what they had been in 1914. The boom busted early. In 1921 the tinplate industry of the world had cut its output in half and total world consumption of tin fell by 1/3. Tin producers became so concerned that they created what was called the Bandoeng Pool. It accumulated stocks held by countries now known as Indonesia and Malaysia, amounting to 28 percent of the combined production of the two countries and about 15 percent of the total world for 1921. The pool holdings were shortly exhausted and thereafter in the years 1924 to 1928, general boom conditions existed for tin.

Jan 1, 1978

By Charles Banks Belt

In 1925, Niggli (1925, pp, 1-69), formulated a physico-chemical, explanation for the origin of hydrothermal ore deposits, from a concept that had appeared earlier in the literature in the writings of Von Groddeck, Stelzner, Beck, de Launay, Kemp, and Lindgren. Niggli proposed that pressure at depth could force volatiles from deep-seated magmas. The volatiles would In turn form pegmatites and then ore deposits as the fluids cooled. This is one view of a general theory of ore genesis that gained secondancy for years among such prominent geologists as Fenner (1926, p, 697) and Emmons (1936, pp. 29-70). It was, proposed that ore deposits were precipitated from solutions or fluids that had escaped or been separated from a deep-seated magma by means of liquid immiscibility or crystallization or gas transfer. This theory is based on the presence of igneous rocks close in space and age to hydrothermal ore deposits in many mining districts of the world. As is well known, there are many ore deposits apparently of hydrothermal origin that are neither spatially nor chronologically related to igneous rocks, In still other localities where there are no hydrothermal ore deposits, igneous rocks occur that are similar in composition to those in mining districts. In view of such facts, the applicability of the Niggli theory to all hydrothermal ore deposits may well be questioned. The chief purpose of this paper is to test the Niggli theory by studying the primary petrology, hydrothermal alteration, and distribution of copper and zinc in silicic igneous plutons supposedly genetically related (in the Niggli sense) to nearby hydrothermal ore deposits, Silicic Tertiary plutons in three New Mexico mining districts were chosen, the Hanover-Fierro intrusive at Hanover and Fierro, the Granite Mountain pluton at Magdalena, and the four outliers of the Lordsburg stock at Lordsburg. First, it had to be established whether the observed plutons were or were not the source of the adjacent ore deposits. This was done by studying the relation between the copper or zinc distribution-and the primary or secondary features in the plutons studied, and the time relations between instrusion and ore deposition. Primary igneous features of a pluton are defined as the minerals, texture, shape, and character of the pluton which were formed prior to the complete solidification of the rock, secondary features include all changes that took place in a pluton after solidification. They are identified by their cross cutting nature or as replacing primary minerals, Under the Niggli concept, it is proved that the ore ions did not originate from the parts of the pluton now visible as immediately adjacent to the ore deposits; it must then be established, if possible', that the ore ions were separated from deeper parts of the intrusive, Some idea as to whether the copper or zinc ions originated from a related magma at depth may be gained by a comparison between the primary (that is, pre-alteration) zinc and copper abundances found in ore localizing intrusive studied and the average abundances for copper and zinc in silicic igneous rocks most recently given in the literature. Finally, the relation between ore deposition and hydrothermal alteration was studied on a regional as well as on a local scale.

Jan 1, 1958

By Peter W. Lipman

In the Rocky Mountain region, variations in Tertiary mineralization correlate with changes in tectonic setting and associated igneous activity that can largely be related to tectonics along the west boundary of the American plate. Successive settings include compressional tectonics and associated continental-arc igneous activity; transitional igneous types associated with intra- and back-arc extension; and basaltic or bimodal basalt-rhyolite assemblages associated with Basin and Range extension in- ward of a growing transform boundary between Pacific and American plates.

Jan 1, 2013

By Bruce Congleton

One year ago this month, we in Central Florida witnessed the beginning of a most exciting and glamorous attraction. After three years of construction and anticipation, Walt Disney World opened its gates near Orlando and during its first year of operation received a flood of over 10 million visitors---half of all who came to Florida last year! The side effects of this newest addition to Florida have been phenomenal. Traffic on heavy days has been backed up for 30 miles from the amusement park along a major interstate highway. Hotels and motels have been jammed packed for months, and reservations are still difficult to make. Gasoline stations, restaurants and souvenir shops are doing a booming business. Everywhere you look as you ride the highways of Central Florida you see the signs of growth. New hotels spring up almost overnight. Golf courses galore. New housing projects and apartments sprawl where orange groves used to be. New roads criss-cross areas which were once deserted. There seems to be no end to the steady influx of tourists and new residents to the Sunshine State. And it's mainly because that we are the Sunshine State that they come. Air and water pollution is and has been at a minimum in Florida. Pollution and emissions are fighting words among some groups dedicated to preserving the bountiful environment we share in Florida. Little wonder then that some of these people display concern when they learn that just 50 miles from the entrance to the Magic Kingdom of Disney, phosphate draglines strip away thousands of acres of land each year to extract one of our nation's most precious

Jan 1, 1972

By Choon K. Quan

Subsidence is a surface manifestation of the underground development and exploitation of minerals, and its impact on the environment is becoming of increased concern, particularly in the face of an accelerating demand for energy and minerals. In the United States, the state-of-the-art in subsidence prediction, control, and prevention and in subsidence-related damage abatement has not progressed to the level achieved in other countries. To bridge this gap, the Bureau of Mines, through its Mining Environmental Research program, is pursuing a comprehensive subsidence investigation, specifically designed to address major problems on the local, regional, and national level.

Jan 1, 1979