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By Joel A. Hunt

The Bunker Hill Mine, located in north Idaho, consists of over 150 miles of passageways within highly fractured and faulted Precambrian metamorphosed rocks. The Bunker Hill Mine was at one time a major producer of lead and zinc; currently it is on inactive but maintained status. Ground water moving along flow paths that have been disturbed by mining reacts with pyrite and oxygen to produce acid water within the mine. Discharge of this acid water averages more than 5 cubic feet per second, with an average zinc concentration of 160 mg/L and pH of 2.8. Treatment of this acid mine drainage is required by the National Pollutant Discharge Elimination System (NPDES). Cessation of all underground activities at the Bunker Hill Mine will not terminate the production of acid mine drainage. Reclamation alternatives that could either reduce the quantity or Improve the quality of the drainage upon mine closure are highly attractive. This project is directed towards delineation of reclamation alternatives based upon an understanding of the characteristics of ground water recharge near the mine. A variety of field techniques were used to identify areas of rapid infiltration and to investigate the ground water flow system associated with the upper portion of the mine in a portion of the Milo Creek drainage. These techniques include Installation of piezometer nests, dye tracing, surface resistivity, dye dilution, spring surveys, and hydrochemical analyses. Sites of direct Infiltration into the mine have been located. These include mine workings directly below perennial streams, intersections between streams and faults, and a caved area adjacent to an ephemeral stream. Results of these investigations indicate that recharge through these sites is not as rapid as suggested by previous studies. Inflow to the underground workings from the ground water flow system around the margin of the mine may account for more mine water than sites of direct infiltration. Recharge control at areas of direct infiltration could result in a net decrease in the quantity of acid drainage from the Bunker Hill Mine. Locations suggested for recharge control are West Milo Creek above the Guy Caving Area, the intersections of the Cate Fault with South Milo and Milo Creeks, and an area of Milo Creek below the Milo Creek Dam that overlies shallow mine workings.

Jan 1, 1984

By P. A. Olubambi1

Representative samples of the hydrothermal vein deposits of the bulk complex sulphide ore deposit, 10 km south of Ishiagu, in Ebonyin State, South Eastern part of Nigeria were collected from two small scale mining companies. The samples were mixed and successively crushed in a jaw crusher and cone crusher, and ground in a rod mill. Characterization was carried out with SEM, EDX, XRD, XRF and ICP-OES. Mineralogical analysis revealed the presence of sphalerite, galena, siderite, pyrite, quartz and chalcopyrite. X-ray Diffractometry showed that sphalerite mineral in the ore occurs as sphalerite ferrous with varied percentage of Zn and Fe within the various sizes while chalcopyrite occurs as a chalcopyrite group mineral with chemical formula Cu2MnSnS4. Results of the elemental analysis showed variations in elemental composition within the different sizes.

Jan 1, 2006

Gippsland has perhaps the most colourful history of exploration of any area in Australia. Hydrocarbons were first discovered in the Gippsland Basin in 1924 when a water well at Lakes Entrance encountered oil and gas shows. In 1942, the Commonwealth and Victorian Governments, in an effort to supplement a wartime oil shortage, sank a shaft near this well and produced 8000 barrels of low gravity oil up to 1956, when the field was abandoned. A total of 64 shallow wells had been drilled in the Lakes Entrance area by that time. Elsewhere in the onshore Gippsland Basin, 30 wells were drilled from 1925 to 1941. In 1960 BHP Ltd was granted an exploration permit covering much of the offshore area of the Gippsland Basin. Esso Australia Ltd joined BHP in 1964 and drilled the Barracouta-1 gas discovery in 1965. Since then over 100 exploration and appraisal wells have been drilled in the basin resulting in the discovery to date of some 3.6 billion barrels of recoverable oil and 8.8 trillion cubic feet of recoverable gas (Current remaining recoverable reserves are 906 million barrels of oil and 5.7 TCF of gas). Exploration in the offshore areas is actively continuing today and new discoveries are still being made.

Jan 1, 1992

By S. M. Spottiswoode

Crush pillars are widely used in mine workings on the Merensky Reef in the Bushveld Complex to prevent panel collapses. Crush pillars are expected to fail as or soon after they emerge from the face and failure should occur non-violently. Unfortunately, violent failure occurs frequently and is said to be the main cause of seismicity associated with mining of the Merensky Reef. Recent work by Napier, Malan, and du Plessis has shown that limitequilibrium quasi-static models are able to simulate pillar failure using three states of strength of rock in pillars, namely intact, residual after failure, and decayed strength after later time-dependent (viscous) weakening. We have previously introduced an additional state of strength to account for the dynamic failure that results in seismic events, and found that this approach could be used to generate synthetic seismic catalogues similar to observed seismicity for deep-level gold mines, where seismicity takes place mostly on advancing faces. The less brittle seam material of the Merensky Reef, compared to the brittle quartzites and lavas of the Witwatersrand reefs, results in little or no face bursting and is modelled with an assumed plastic strain of some 0.005 over an effective stope width of 2 m before failure. When this plastic yield is surpassed, we allow the reef to fail ?seismically?. We show that synthetic seismic catalogues modelled in this way have some of the features of observed seismicity. Analysis is greatly facilitated using our custom-built software that reads the mine?s survey data into a database and presents results in an interactive graphical form.

Jan 1, 2014

The Wamum and Idzan Creeks Prospect, located 79km W of Lae, Morobe Province, Papua New Guinea (PNG) was discovered by the exploration arm of Conzinc Riotinto of Australia Pty Ltd (CRAE). The detailed surface exploration and 11 vertical holes drilled by CRAE, combined with the recent work by Highlands Gold Limited, indicate the occurrence of porphyry copper-gold mineral- isation and associated alteration. The prospect occurs within andesitic volcanics of the Middle Miocene Langimar Beds. It is bounded by NE trending faults to the NW and SE. The alteration and mineral- isation is hosted in the andesitic tuffs adjacent to high level quartz diorite and hornblende diorite stocks. A NW trend to alteration and mineralisation is obvious in Wamum and Idzan Creeks. The main alteration type is propylitic with minor zones of potassic alteration. A late sericite-quartz-kaolinite-pyrite alteration overprinted the earlier alteration and mineralisation. Copper and gold mineralisation is related to a quartz-carbonate-chalcopyr-ite-pyrite (¦ bornite) vein stockwork and biotite ¦ K-feldspar alteration. The mineralisation system at Wamum and Idzan creeks is low in total sulphides. It is considered as a high- level fracture-controlled system with limited low grade Cu-Au mineralisation.

Jan 1, 1991

By V. Kecojevic

Environmental and economic costs related to equipment fuel consumption and carbon dioxide (CO2) emission present a substantial challenge to the mining industry. Haul trucks are an integral part of the overall surface mining system and they consume a substantial quantity of fuel. Consequently, they produce a significant amount of CO2. The objective of this research is to (i) establish a mathematical relationship among a truck?s fuel consumption, power and engine load factors and (ii) determine the amount of a truck?s CO2 emission and the associated cost that may arise from potential CO2 legislation. In order to achieve these objectives we have considered original equipment manufacturer (OEM) haul trucks, commonly used in surface mining operations. The research presented here may be used by mining professionals to help determine the cost and environmental burden of the trucks? application, and efficiently manage energy consumption.

Jan 1, 2011

The following pages discuss the objectives, the background, the scope and a statement of the problem of the study of methods to improve the pillar extraction practices in underground coal mines. 1. OBJECTIVES The objectives of this project were: ? to determine the principal factors contributing to high accident frequency and severity in both conventional and continuous mining operations; ? to compare and evaluate the safety aspects of the "open end" and "split and fender" systems of pillar mining; to establish basic data required to decide what constitutes an adequate pillaring plan that will optimize efficiency, recovery, and safety; ? to determine what measurements or information should be collected, (e.g. roof sag, pillar stress,) to make on-the-spot judgment of impending roof or pillar collapse; ? to make recommendations to improve existing methods or to insure proper techniques are implemented, and ? to suggest areas where additional studies or new research may be of value.

Jan 1, 1975

Fresh coal refuse was sampled at 21 US mines. Five of the sites were drilled, sampled and tested more extensively. Field tests included Standard Penetration tests, and in-situ density determinations. Laboratory testing included specific gravity, gradation, maximum, and minimum density tests, as well as 9-inch) drained triaxial tests, 9 and 10-inch, permeability tests, slake-durability tests, and accelerated slaking tests. Some refuse sites had significantly lower shear strengths and permeabilities in old, slaked or weathered material than in fresh refuse. Testing did not show useful correlations between strength and permeability changes and other material properties which could serve as "predictors". Testing of refuse under "accelerated slaking" conditions showed promise as a comparative tool and as a potential means of preparing artificially aged samples for evaluations of long-term behavior. The state-of-the-art in slaking research, and the implications of slaking on coal refuse disposal, and on practical methods of managing slaking, were also studied.

Jan 1, 1981

By R. Karl Zipf

The sudden, violent collapse of large areas of room-and-pillar mines poses a special hazard to miners and mine operators. This type of failure, termed a "Cascading Pillar Failure" (CPF), occurs when one pillar in a mine layout fails transfering its load to neighboring pillars causing them to fail, and so forth. Recent examples of this kind of failure in coal, metal and nonmetal mines in the U.S. are documented. Mining engineers can limit the danger posed by these failures through improved mine design practices. Whether failure occurs in a slow, nonviolent manner or in a rapid, violent manner is governed by the local mine stiffness stability criterion. This stability criterion is used as the basis for three design approaches to control cascading pillar failure in room-and-pillar mines, namely, the containment approach, the prevention approach, and the full extraction mining approach. These design approaches are illustrated with practical examples for coal mining.

Jan 1, 1996

By W. H. Ryback

When a fire or explosion occurs in an underground coal mine, the atmosphere guickly becomes irrespirable. Highly irritant smoke and toxic levels of carbon monoxide and dioxide are produced, and consumption of oxygen by the fire or blast can reduce its concentration below that needed to support life. Work parties entering such a hazardous atmosphere for rescue or recovery operations are required to use, as their primary respiratory protection, a fully self-contained breathing apparatus of at least two hours duration. Apparatus used in this role has primarily been of the closed circuit rebreather type, using pressurized oxygen storage and chemical removal of expired carbon dioxide. Typically, commercial self-contained breathing devices for mine rescue have been heavy, bulky, and uncomfortable to use. The McCaa apparatus, long the industry standard, represented the best art available when it was First designed in 1926. It weighs 41 Ibs., protrudes about six inches above shoulder height, and provides breathing gas at temperatures up to 120° F. More recent designs, such as the Drager BG174A and Scott Rescue-Pak, using modern light weight materials and fabrication techniques have improved on all parameters of the McCaa to some extent. It was the intent of the Bureau of Mines, acting under the authority of the Coal Mine Health and Safety Act of 1969, to fund the development of a new self-contained breathing apparatus which would incorporate the best available technology and serve as a benchmark for future commercial designs, as the Bureau-sponsored McCaa had 45 years previously.

Jan 1, 1974

By Parkhurst D. H

It is shown that a differential colorimetric technique can be used as a routine method for the estimation of titanium in beach sands, and their ore dressing products. The method will tolerate the presence of most of the other elements usually found in beach sands. The accuracy is shown to be within the limits of ±0ò31 per cent for concentrates containing more than 95 per cent titanium dioxide and ±1 per cent for tailings containing 0ò2 per cent titanium dioxide. The method is described for use with a Hilger "Spekker" absorptiometer.

Jan 1, 1957

When asked to lecture at Bendigo on the geological factors that determine the depths of ore deposits, I hesitated for a little before agreeing to lecture on the theory of deep ores in the city world famous as the pioneer of deep gold mining. If there be one place, wherein the conditions of deep-seated ore deposits should be sufficiently well understood, it is the city where the 180 mine made its bold plunge to previously neglected depths; and where the record of that famous mine has been broken by the skill of the managers, and the pluck of the proprietors, of the New Chum Railway and Lazarus mines.In the face of such practical triumphs, theoretical discussion may seem a waste of time, especially since it is often dedared that the existence of such deep-seated ores was denied by geological theory. This assertion is, however, startling since the oldest and best supported geoiogical theory of ore deposits, has taught for more than a century tliat ores must descend far below the regions of practical mining. This charge against Victorian geologists is generally based on opinions attributed to the late Sir Fredrick McCoy. It has been repeatedly affirmed that he declared that gold cannot occur pelow a depth of 300 feet. But so far I have not been able to discover that McCoy ever made any such assertion or ever held such a view.

Jan 1, 1902

In late 1989, first-pass reconnaissance exploration delineated a 4km x 6km geochem- ically anomalous area centred 10km WNW of Kainantu in the Eastern Highlands Province at 6¦13'S and 145047'E. The area, named the Basangka prospect, lies between 2 200 and 2 400m asl. Interest in the area was prompted by a 14ppm Au assay of a silica-pyrite breccia float sample taken near Henkai village. The prospect was defined after several acid-leached silica- pyrite breccia and comb textured quartz float samples returned assays above lppm Au and relatively high Ag. Very encouraging and anomalous Au values were obtained from panned concentrates, despite the absence of visible Au colours. Several pan concentrates returned greater than 1mg Au and it is believed that the Au occurs as inclusions within iron oxides which were originally pyrite. In this early stage of prospect exploration, any Au value above 0.lppm in- 150# fraction stream sediments is treated as anomalous. Rock chips, panned concentrates and -150# fraction geochemistry all vividly define the areas of interest at Basangka.

Jan 1, 1991

By Wayne Trudel, Eric Saderhold, Lloyd McEvers, Lori Clarke, Charles Lynn Bolin, Leroy Schutz

Editor’s note: This is the second part of a two-part series on how mine geologists added about 141t (4.53 million oz) at Newmont Mining’s gold operations in Nevada during 2003. Part one (ME, July2004, pp. 19-26) showed how cross-functional teamwork among mine geologists, engineers, metallurgists and operators added $65 million in revenues at Newmont’s Gold Quarry Mine. Part two deals with how this same cross-functional team added about 25.8 t (830,000 oz) of gold reserves and two years of life at the company’s LoneTree Mine. This was done through improved reconciliation methods, pit optimization designs and updated geotechnical parameters. Part two also discusses how Newmont’s Nevada mine personnel added about 62.2 t (2 million oz) of gold reserves at its Twin Creeks Mine, extending the mine’s life by several years. The Lone Tree Mine is a sediment-hosted, micron gold deposit. It is dominantly situated in the Golconda thrust footwall. The north-south trending Wayne Zone fault controls the highest-grade ores and

Jan 1, 2004

The 1969 Lignite Symposium was held at Grand Forks, N. Dak., on May 1-2, 1969. Cosponsored by the University of North Dakota and the Department of the Interior, Bureau of Mines, the meeting was the fifth in this series. Registrants from many States and Canadian Provinces attended the meeting representing many segments of energy-oriented companies, State and Federal Government, and universities. At 2-year intervals, these symposia provide a common meeting place where recent research and developments in technology and utilization of energy resources with emphasis on solid fuels (lignite) are presented. Proceedings3 of the previous symposia including a Forum held in 1958 have been published.4

Jan 1, 1970

By S. S. Venkata

This volume describes a comprehensive program of research into the reliability of mine electrical power system components and the resultant reliability of the total system. The research effort encompassed analytical models, laboratory testing and field testing. The analytical work included definition of terms, fail rate functions and distributions, failure rate estimation and techniques and procedures for theoretical reliability assessment. One of the primary mine power system components addressed in the study was the ac molded case circuit breaker. This device is known to have low reliability and hence an unfavorable impact on mine safety and productivity. Ac molded case circuit breaker reliability was studied by analytical means, laboratory testing and field monitoring. A similar three-pronged' effort was made to study the reliability of undervoltage relays/releases. Particular emphasis was placed on new solid state undervoltage relays. The reliability of bulk power components, such as trailing cab les, motors, control gear, and other equipment, was assessed by gathering maintenance records from active mines. These data were compared to similar records from other industries. The work was extended to include the reliability, availability, maintainability and safety of these components.

Jan 1, 1979

By Steve Kral

The mining industry has had three difficult years. Commodity prices have remained low and investor confidence in the industry has been shaken. And even though the Asian economy appears to be improving, it will be some time before this improvement will translate into better commodity price conditions for mining. In addition, increased environmental and social restrictions that have been placed on the industry in developed and developing countries have made mining a more difficult proposition. And, if that is not enough, the global mining industry has found itself in fierce competition with Internet businesses for investor capital. Despite that gloomy picture, more than 10,500 mining industry professionals from about 70 countries gathered in Toronto, Ontario March 5-10, 2000 for the Mining Millennium 2000 conference. This meeting was a joint effort between the Canadian Institute of Mining, Metallurgy and Petroleum(CIM) and the Prospectors and Developers Association of Canada (PDAC).The joint meeting also featured two trade exhibitions and more than 150speakers. PDAC’s trade show attracted about 400 exhibitors and an additional 200 in the concurrent Investors’ Exchange. CIM’s exhibition attracted about 600 equipment and service companies.

Jan 1, 2000

By Robert L. Lagace

The objective of this task was to perform theoretical analyses related to identifying and increasing the understanding of wireless propagation mechanisms in mines, and for predicting the performance ranges and limitations of proposed systems. This was to be achieved by building on and extending previous ADL work* and utilizing experimental data as they became available in the radio frequency bands of interest. B. TASKS Theoretical radio wave propagation investigations undertaken on this task centered on three areas. The first area dealt with extending previous UHF wireless propagation results*: to estimate the losses caused by the presence of haulage vehicles such as trains in coal mine tunnels; to estimate the propagation losses and wireless communication ranges expected along a longwall coal face tunnel; and to assess the applicability of previous analytical approximations to tunnels having reduced crossectional dimensions, such as those found in low coal and in the presence of haulage vehicles. The second area dealt with the development of a suitable propagation model to adequately explain the unexpected, highly favorable LF to MF band wireless radio wave propagation behavior experimentally observed in Consolidation Coal Co.'s Ireland mine. The third area dealt with the formulation of a model for evaluating the overall system transfer function and transmitter requirements for a hoist shaft LF communications system, taking into account the hoist rope/shaft transmission line characteristics, the cage and sheave wheel line terminations, the signal inductive couplers, and hoist shaft signal and noise data.

Jan 1, 1975

By William H. Schiffbauer

The Bureau of Mines has developed a passive encoder for range knobs, a device that automates the task of obtaining the range settings from devices or instruments to be input to microcomputers. It is easily constructed and installed and will not disrupt the device to which it is being attached. It consists of a custom knob and a small printed circuit board that has light-emitting diodes and magnetic reed switches attached. A ribbon cable connects it to a microcomputer. This encoder eliminates one source of human error in an automated process.

Jan 1, 1983

By J. P. Kennedy, O. A. Bascur

Large metallurgical complexes have more data than a small city and these data change as internal and external conditions evolve. Staffing turnover hinders experienced-based decisions especially with simple tools like spreadsheets. Lack of current information can contribute to decisions that result in significant deterioration in the quality of operation. Timely, unified information from sophisticated analyses presented to the broadest possible reach will improve operation. The major innovation is the addition of the web browser to the suite of software people will use with no training – the other two are spreadsheets and graphical presentations – and the consistent organization and transformation of the real time data to support broad access. This paper describes the data transformations and presentation methods necessary for a Web view, especially the special needs of real time data and analysis required for active operations decision-making. Many people inside and outside the complex, not just operators, need timely information that is abstracted, aggregated, organized and unified. Unification and aggregation of real time data presented via the Web opens a new paradigm for collaboration. The analysis tools are as important as the data. These rule-based tools add significantly to the operations database in the form of results stored for viewing with plant data. Mining and metallurgical plants already use many sophisticated analysis tools such as predictive maintenance policies based on statistical analysis vibration analysis, and oil and lube analysis for critical equipment. These add real time events, similar to an alarm package, and unified production information to the operational database. Simple models are used on line to create key indices that provide a real time indication of performance. Key indices include metrics for losses due to plant availability, performance efficiency, and overall process equipment effectiveness. These additional data in the operations database are used for early fault detection, increased production, better quality, higher availability of equipment and faster detection of process bottlenecks. An important feature is the ability for people to create their own key indices and store the results for use by anyone in the plant historian, but accessible by a browser. Keywords: plant information, principle components analysis, data reconciliation, gross error estimation, Internet, Word Wide Web

Jan 1, 2002