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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 D. A. Barr

High-grade gold-silver mineralization associated with electrum and argentite was discovered in a quartz vein at the Chappelle property, 273 km north of Smithers, B.C., in 1969 following a regional geochemical reconnaissance program in the Cassiar-Omineca Mountains. Subsequent exploration resulted in the discovery of numerous quartz veins with associated precious-metal values in a belt 17 by 3 km in area centrally located within Toodoggone Group volcanic and sedimentary rocks of Lower to Middle Jurassic age and a window of Takla Group volcanic rocks of Upper Triassic age. More detailed investigations, consisting principally of 5677 m of surface drilling in 57 holes and crosscutting, drifting and raising on Chapelle Vein A, has outlined a high-grade gold-silver-bearing shoot with a strike length of 200 m, an average width of about 3 m and extending to an average depth of about 40 m below surface.

Jan 1, 1978

By Jos. Kalbhenn

PART of the plan of re-allocation evolved by the engineers of the Dominion Steel and Coal Corporation in 1932 to retard the rapid advance of the submarine workings seawards was the opening of Dominion No. 20 Colliery, in the Harbour seam, by a pair of cross-measure tunnels from the workings of an older mine working the Phelan seam, which lies 430 feet below the Harbour seam. The tunnels, 8 ft. by 13 ft. in size, were started away from the old workings of Dominion No. 2 at a point 1.5 miles beyond the shore line and were driven on a rising grade of 1 per cent for a distance of 5,335 feet, tapping the Harbour seam at a point 2 ¼ miles off-shore. For transportation and ventilation, shafts and roadways already existing in the Phelan seam were made use of during the stages of development and up to the present time. One of the two tunnels served as a main haulage road and an intake airway, and the other as a return airway and travelling road. However, as the workings of this new colliery expanded, the need for additional airways arose as was anticipated when the plans for the development were formulated. To meet this need, work was started on October 1st, 1942, to establish a new opening between Nos. 2 and 20 Collieries in the form of a vertical shaft to provide a passageway for the ventilating air current of some 250,000 cubic feet per minute on its return to the upcast shafts in No. 2 Colliery, thus making both tunnels available for intake airways. In the interest of safety, speed, and economy, the shaft was raised from the Phelan to the Harbour seam. It is 20 ft. by 12 ft. in size and, with the exception of three timbered compartments across the narrow end, is untimbered. One of the three timbered compartments housed the ventilating tubing and pipe lines, the centre one served as a cage-way for hoisting men and material during the operation of raising, and the third one contained a ladder way. The rest of the shaft was filled with debris during the period of shaft raising.

Jan 1, 1944

By Christopher C. Jobes

Computer-assisted control of a mining machine can place the operator in a safe, remote location. A guidance system aids remote positioning of a mining machine by determining its position and heading. The mechanical position and heading system (MPHS) is one of several guidance systems being developed at the U.S. Bureau of Mines. The MPHS uses linear position transducers (LPT's) to provide navigation information during face maneuvers. This report presents an overview of the MPHS theory and implementation, including recent design modifications made for more successful underground testing. This report also presents the experimental setup and procedure for the underground test. The test showed that the MPHS provides reliable and accurate results and can, therefore, provide useful guidance information for face navigation.

Jan 1, 1992

By John B. Ivey

This is a geologic study of the U.S. Bureau of Mines Oil Shale Tract in the Piceance Creek Basin of Rio Blanco County, Colorado for the preparation of a set of detailed surface geologic maps, measurement and identification of joint attitudes and frequencies, and the classification and mapping of the soils of the area.

Jan 1, 1978

A unity of viewpoint emerged from the workshop. The concept that transmission is via characteristic modes was a common theme in many of the presentations. Also, the confusion an the meaning of monofilar and bifilar to describe these dominant modes was cleared up. But, there was still a healthy divergence of opinion on what constitutes an optimum system. It was generally agreed that further analytical and experimental work is definitely needed. In particular, it was stressed that independent measurements of the constitutive properties of the electromagnetic environment are needed. Also, there was considerable concern that laboratory measurements of rock samples could lead to misleading results for the effective conductivities. Also, there was a general recognition that over simplified propagation theory should not be used to interpret field data. From a theoratical and practical point of view, it was realized that mode coupling plays a vital role in the transmission channel. One must not only understand which and how many propagation modes are excited by the transmitting antenna, but the conversion of energy from one mode type to another must be accounted for. This conversion can either be done intentionally (by fixed mode convertors) or non intentionally (by random wall roughness). In fact, mode conversion can be quite complicated when various propagation paths exist such as when insulated cables, leaky feeders, grounded rails, coal seams, etc. all convey portions of the electromagnetic energy. However, this state of affairs should be regared as an. opportunity for extended communication coverage in mines rather than a limitation of a desig. procedure based on preconceived notions of the dominant propagation mechanism.

Jan 1, 1978

By Judy K. Todd

Double benching has been utilized as an excavation technique in open pit mines for many years. This process involves drilling, blasting, and excavating the material for the design bench height. A second bench is then excavated without the creation of a catch bench, i.e. only minimal offset from the first bench face is allowed when drilling off the second bench. The result is a double high bench face or double bench. When drilling off the second bench, the offset of the drill from the bench face projects the lower bench face into the pit up to an extra five meters. This reduces the maximum attainable bench angle, enhances the probability of rock escaping the catch bench and increases the overall strip ratio. The generally utilized process of trim blasting also can impact on the final bench profile by contributing to blast damage of the face. BHP Billiton Diamonds Inc., Ekati Mine Diamond MineTM, has pioneered the usage of a technique that eliminates this offset. Double benching is accomplished by drilling a single, 30m pre-shear (two 15m benches) to define and protect the final bench profile. This article provides a comparison of the attained face angles obtained in the field utilizing both of the above methods, as well as a comparison with the analytically predicted angles prior to excavation.

May 1, 2002

By Andrew McGrath, Geraldine Lyons, Sarah Barcelona

In the dynamic and challenging modern industry landscape, understanding and unleashing the true role and contribution of technical teams is crucial to business success. The cyclical nature of industries has led to shifts in the technical professional’s place within the organization and the technical skills that are desired most. This paper reframes the pivotal role that technical professionals play within complex operating assets to maximize value and realize full potential. This investigation focuses on the Rio Tinto Kennecott Technical group’s cultural journey, which is underpinned by an investment in its people. The conflict between legacy industry beliefs and the necessity for cultural change emerges. This is illustrated by a deep dive into the evolving case study of Kennecott’s Bingham Canyon Open Pit Mine Technical team. Here, a multi-faceted approach to cultural change is helping to unlock the team’s contribution to the life extension of an aging asset. Guided by a vision and strategic roadmap, this approach is part way through a 5-year implementation period and is yielding encouraging business outcomes.

Feb 1, 2024

By K. J. Ladwig

The Bureau of Mines conducted a field investigation of the water quality in inundated underground coal mines in the Northern Anthracite Field, eastern Pennsylvania. Water samples were collected at multiple depths from nine abandoned mine shafts in the Wyoming Basin, ranging from 68 to 650 m (223 to 2,132 ft) in depth and intersecting as many as seven mined seams in a single shaft. The shafts were also monitored for fluid resistivity, fluid temperature, Eh, and pH using downhole instrumentation. The monitoring program showed that the formerly highly acidic mine water is now slightly alkaline. Sulfate concentrations decreased as much as 74 pct in the flooded workings and 54 pct at a mine water discharge from values reported in 1964 and 1968, respectively. These data are consistent with the inhibition of pyrite oxidation and gradual flushing of oxidation products in flooded mine environments. The monitoring program also revealed significant vertical stratification in water quality in five of the nine shafts, each characterized by two easily recognizable zones. The transitions between zones were sharp, marked by rapid changes in Eh, pH, and ionic composition, the upper zones being less contaminated than the lower zones. The development of stratification appears to be a function of shallow localized flow conditions, arising primarily from the relative positions of mine openings and structural features of the coalbeds.

Jan 1, 1984

By Hal J. Kelly

A number of problems that developed in processing the halloysitic clays of eastern Washington and northern Idaho were investigated by the Bureau of Mines. The deflocculating effect of tetra sodium pyrophosphate is compared with several other compounds, and on the basis of current theory, the advantage of sodium pyrophosphate as a deflocculating agent is explained. The adsorption of the sodium ion by clay in a clay"-water system was established by a radioactive tracer technique, and the deflocculating action of sodium pyro- phosphate was postulated. The effective dispersion of the halloysitic clays was limited by the occurrence of tightly bound aggregates of small, individual crystals. Disaggregation of the agglomerates was investigated by liquid extrusion and ball milling of dilute slurries and by extrusion of the clay in a plastic state. The greatest increase in the production of small particles was by high? pressure liquid extrusion.

Jan 1, 1963

By Wendell L. Reich

Percussion drilling dates back to the hand operated star drill and hammer. Eventually steam and compressed air were substituted for muscle power and the mechanical percussion drill was born. From the hand held jack hammers, driving a forged steel bit into the rock, there evolved the jack leg, the rubber tired and crawler mounted drill carrier with automatic feed, increasing power and reducing man?s muscle requirements. Because the reaction of a blow on one end of a piece of steel has to be transmitted to the other end there is a limit to the depth or length of drill steel that can economically be used in out of the hole percussion devices. During the late 1800?s there is evidence that designers were attempting to put the percussion tool at the bottom of the hole, directly on the bit, in order to avoid the long drill steel which absorbed much of the blow, leaving little to be applied to the bit and the rock being drilled.

Jan 1, 1972

By CIM Mineral Resource, Mineral Reserve Committee

The CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines (MRMR Best Practice Guidelines) were prepared by the Canadian Institute of Mining, Metallurgy and Petroleum's (CIM) Mineral Resources and Mineral Reserves Committee (CIM MRMR Committee) to update an earlier version that was accepted by CIM Council on November 23, 2003 (CIM, 2003). These 2019 MRMR Best Practice Guidelines supersede and replace the November 23, 2003 version of the MRMR Guidelines. These 2019 MRMR Guidelines are not intended to be prescriptive and are not intended to provide detailed and exhaustive instructions for preparation of Mineral Resource and/or Mineral Reserve (MRMR) estimates. Rather, they are intended as general guidance to assist professional geoscientists (or equivalent) and engineers (or equivalent) in preparing high quality estimates of MRMR that incorporate sound geoscientific, engineering, evaluation and design practices. They are based on well-established estimation and mine planning principles and are designed to provide general guidelines of best professional practices employed in the preparation of MRMR estimates. Although the 2019 MRMR Best Practice Guidelines are intended for use by Canadian-based mining/exploration practitioners, many of the concepts and practices presented herein are in general agreement with current industry practices in jurisdictions with membership in the Committee for Mineral Reserves International Reporting Standards (CRIRSCO). For this document, persons preparing MRMR estimates are called Practitioners. Preparation of MRMR estimates should be carried out by Practitioners who either hold the status of Professional Geoscientist (or equivalent) or Professional Engineer (or equivalent), or who prepare the estimates under the supervision of a Professional Geoscientist (or equivalent) or Professional Engineer (or equivalent). For the purposes of this document, all references to reporting describe such necessary reports and related documentation that are created as part of the normal-course work flow of preparing MRMR estimates for internal purposes. For clarity, all public disclosure of MRMR estimates made by, or on behalf of, an issuer and intended to be, or reasonably likely to be, made available to the public in a jurisdiction of Canada must comply with the requirements of National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101), as amended from time to time. At least one Qualified Person (QP) must take responsibility for each part of the estimation process when publicly disclosing the results of MRMR estimates. The intended audience for these 2019 MRMR Best Practice Guidelines includes Practitioners at all levels of skill and experience, government agencies, academic institutions, and the public.

Nov 29, 2019

By T. Lane Carter

(Canal Zone Meeting , October , 1910.) INTRODUCTION. IT is a curious fact that while in our Transactions there are papers dealing with mining-districts in all parts of the world, in Europe, Asia, Africa, and Australia, there is not one which describes the mining possibilities of Nicaragua; our near neighbor. To be most interested in distant objects, like the moon, .and to neglect what lies at our feet, appears to be a trait of human nature. The neglect of Nicaragua is not confined to the American Institute of Mining Engineers. In no other transactions am I :able to find papers dealing with mining in Nicaragua, some parts of which are as much in need of discovery and research as the North Pole.. I hope this paper will be the precursor of many others to be printed in our Transactions, dealing not only with the mining possibilities of Nicaragua, but with the whole of Central America, where there are vast areas awaiting skill and capital for their development. Much of this capital and skill should come from the United States in the future, although it is probable that European capitalists, when they appreciate fully the possibilities, will investigate more and more the mining-resources of Nicaragua and other Central American republics. Fig. 1 is a sketch-map of Nicaragua showing the principal mining-districts. II. HISTORY. Mining in Nicaragua did not begin yesterday. It was commenced by civilized man when the Spanish conquerors penetrated into the interior and forced the natives to procure the precious metal for them. It is strange that the Spaniards did not find more gold, and work on a scale as extensive as in Colombia and other parts of South America. Probably in Nicaragua the Indians covered up most of the rich prospects

Dec 1, 1910

By Otto L. Schumacher

The Overthrust Belt in portions of Montana, Idaho, Utah, and Wyoming, an area that has contributed generously to the Nation's mineral supply, is one of the few remaining oil and gas frontiers on the North American continent. Determination of the oil and gas potential and development of mineral resources of the area have been affected by a variety of land withdrawals and other restrictions, The purpose of this study is to determine the extent of these withdrawals and restrictions and to discuss the mineral resource potential within the study area. Statistics in this report refer to land status on January 1, 1979. At that time, of the 27.3 million acres of Federal mineral lands within the study area, applications tor Federal oil and gas leases for more than 4,4 million acres (about 16 percent) were pending; the average length of time was 2 years. Federal oil and gas leases covering 8.8 million acres were also on record. Although drilling has occurred on some of these leases, others are subject to restrictions that discourage or prevent development. Some in fact contain stipulations disallowing any development.

Jan 1, 1981

1. Domestic Production and Use: Twelve companies operated 31 primary aluminum reduction plants, three firms accounting for 66% of production. Washington, Oregon, and Montana accounted for 32% of the total production; Gulf Coast States, 25%; Northern States, 29%; and other Southern States, 14%. Output of primary metal in 1973 was valued at $2.2 billion. About 80% of the secondary recovery was from new aluminum base scrap and 20% was from old scrap. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1972, building accounted for 28%; transportation 19%; electrical, 13%; packaging, 16%; and consumer durab1es, 10%.

Jan 1, 1974

By K. Muralidharan, P. R. Rao, M. Momayez, K. A. Runge

The evolution of trapped geothermal heat in hot underground mine along with emission of toxic gases and dust during mine activity makes the mine environment unfavorable is hazardous to worker’s health. This imposes significant demand on cooling and ventilation systems. As a result, substantial costs are incurred while implementing environmental regulation processes to dissipate the heat and provide comfortable working conditions. Thus, as an alternative, the development of cost effective materials to act as efficient thermal insulators is on the rise. Thermal conductivity is an important property that is a direct measure of a material’s ability to facilitate/deter heat flow. In addition to their superior chemical resistance, adequate mechanical strength, abrasion and fire retardant as well as environmental benefits in comparison to existing building materials such as ordinary Portland cement, aluminosilicate based geopolymers are now gaining widespread interest as promising thermally insulating and sustainable materials. This paper begins with an overview of geopolymers, transitioning into a discussion of recent developments in the field of geopolymer development as a thermally insulating material broadly classified into: filled geopolymers and porous geopolymers resulting in structures with enhanced ability to impede heat flow.

May 9, 2020

By Pat McCarran

WHEN this Government was founded, the framers of the Constitution wrote into that instrument a provision that Congress should "coin money and fix the value thereof;" and the Constitution prohibits making anything but "gold and silver" lawful money. So silver is written into our basic law. Shortly after President Washington took office in 1789 the Congress passed the first Mint Act, setting up the U. S. Mint. In that Act, signed by President Washington on April 2, 1792, the weight of the American dollar was fixed, and it was provided how much silver should be contained in a silver dollar and how much gold should be contained in a gold dollar. It was decided that 371 1/4 grains of pure silver was to be the standard dollar of America. That standard with respect to the pure silver content of the dollar has never changed.

Jan 1, 1947

By Douglas W. Fuerstenau, Pradip Pradip

The design and development of selective flotation collectors has been the key to the remarkable success of flotation in beneficiating complex, difficult-to-process ores. Sustained research efforts in the field over the past hundred years have led to delineating the scientific basis of selective mineral flotation in terms of the crystal chemistry and the surface and colloid chemistry of minerals including their solubility, and the aqueous solution chemistry of added reagents. It is now well-established that the electrical double layer theory (EDL) is the most powerful means of quantifying the relative strength of mineral-reagent interactions in the case of nonsulfide minerals. We illustrate the utility and the power of the EDL in delineating the science underlying selective mineral flotation with the help of a few examples taken from our own work, in particular on the selective flotation of rare-earth minerals (bastnaesite) from associated semisoluble minerals (barite and calcite) using alkyl hydroxamate collectors and the flotation separation of lithium-containing minerals (spodumene) from associated alumino-silicate minerals with oleate (fatty acids). Both of these mineral separation systems are of contemporary research interest and of immense value to the industry today. Recent advances in utilizing molecular modeling computations, particularly in the context of quantifying the effect of crystal chemistry and the relative distribution of adsorption sites available on mineral cleavage planes, are also reviewed.

By Russell R. McLellan

The Tertiary channel gravel deposits in northern California were selected Or detailed investigation by the U. S. Bureau of Mines as part of a national program to locate potential sources of gold that might be developed rapidly by large-scale mining operations. Five bureau research centers representing mining and metallurgy subsystems coordinated their efforts in a team operation to identify and investigate possible solutions to the problem area, that long have discouraged the resumption of large-scale mining in the deposits. This report summarizes the individual investigations, conclusions and recommendations conducted and prepared by all mining subsystems research groups after the completion of two years of field work at the deposits on San Juan Ridge in Nevada County, California. The studies indicate that modern mining technology can cope with the environmental problems that closed the immense hydraulic mines in 1,884. however, they also indicate that mining can be conducted with only marginal profits its unless the price of gold remains substantially above $70 per ounce or unless sufficient by-products can be recovered and sold to place the average value per cubic yard of gravel into a positive commercial range. The by-product potential of the Tertiary gravels remains to be investigated in more detail.

Jan 1, 2012

By Arthur R. Rattew

In conjunction with the research study of the Coronation Mine recommended by the National Advisory Committee on Research in the Geo-logical Sciences and coordinated by the Geological Survey of Canada, Canadian Aero Service Limited per-formed a detailed, low-altitude air-borne survey over a block of ground encompassing the .Coronation Mine. The in-phase/out-of-phase air-borne electromagnetic data are com-pared with "horizontal-loop" ground data with reference to: size and nature of conductors detected; criteria in selection of targets for drilling. In-formation provided by Hudson Bay Mining and Smelting Company on their drilling of the numerous conductors in the area is employed in this comparison. The merits of combining a sensitive airborne magnetometer with an air-borne electromagnetic unit are discussed. The magnetic data are considered very important in assessing conductors as prospects for commercial sulphida deposits in this area of numerous electromagnetic anomalies. The "Coronation" survey illustrates

Jan 1, 1962