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By A. Livingston

This paper on mining practice at the Fresnillo silver mines is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts of North America. Two classes of ore are produced at Fresnillo. A low-grade oxidized silver ore; end a complex-base sulphide are containing gold, silver, lead, zinc, and copper. This paper is confined to a discussion of operations relating to the production of oxidized silver ores. To date, more than 10 Million tons of this ore rave been mined. The present (June, 1931) daily production is 2,000 tons of ore, and approximately 600 men are employed in the mining operations.

Jan 1, 1932

By Mark E. Emerson

1967 will be remembered as the year the world realized it was running out of silver. In May of this year a new era in tin the history of the white metal was begun as the power of the U.S. Treasury to regulate world .silver markets was staggered by one of the most intense speculative flurries in recent times. In the past few months the price of silver has risen from $1, 29 to over $1.80 per troy ounce and with it have spiraled the prices of a host of silver-bearing consumer items. Legislation has, been enacted to conserve our coinage and meager silver stocks and today large quantities of non-existent silver are trading hands at a fast pace on the commodity exchanges throughout the world. Now that the price of silver has been set loose, forces are in motion to dull the world's appetite for silver. At the same time there is strong incentive to provide greater quantities of silver to satisfy the world's hunger' for the metal.

Jan 1, 1967

By H. R. Banks

IF you have ever travelled in the valley lying between the Selkirks and the Rockies in the East Koorenay district, you will have noted that the former mountains are rounded and massive, while the serrated peaks of the latter, fingering into the sky, bring an entirely different. picture. These two mountain ranges, with the comparatively level valley between, serve splendidly to introduce the subject for discussion. It is rather strange that, despite the fact that wear is undoubredly the greatest force with which human ingenuity bas to contend, it has come in for very little study from the stand point of pure science. Empiricism has been the sole ally in the fight for improvement! That we may have a clear understanding as to what we mean by wear, I would include in the term the breaking dawn of ail solid matter, from the natural wearing dawn of the mountains previously mentioned, to the hale in the mill pipe-line, which forces one to shut-down-usually at some un-earthly hour-to carry out a repair. It seems a far cry from mountains to mill launders or pipe-lines, but, magnified sufficiently, most of the materials with which we have to deal would show surfaces not unlike those we see around us. The progressive steps of wear, or ?erosion' as our geological friends would prefer to term it, are exemplified in the two ranges of mountains and the valley between. True, the wearing dawn by natural forces is a slow process. The aeons which have passed since first these mountains were formed seem endless. The natural forces pitted against them seem puny in the light of the interminable rime that has been needed to effect the changes. But here, as in the case of the materials with which we are dealing day by day, the combination of many forces ultimately brings about that condition which we describe as 'worn out'. In the case of the mountains, it is when they are finally levelled into plains, and in the case of equipment which we use, it is when that equipment will no longer serve its purpose.

Jan 1, 1943

By Yongbao Zhu

The Ag2O-mediated reactions of cycloaurated compounds with a general formula Au(L)Cl2 (L = bi-dentate C?N ligand) with thiosalicylic acid, N-acetyl cysteine or 1,2-benzenedithiol in DMF proceeds via ligand substitution of the Au?Cl bonds to afford the S-O and S?S adducts all in good yields. The reactivity of the dichloro, S-O and S-S adducts towards thiols were examined by reacting with cysteine in an aqueous medium, revealing that all of Au-Cl, Au-O and Au-N are labile for thiol displacement. The measurement of the inhibitive activities of these compounds against human cathepsins B and K showed that the dichloro and S-O adducts are effective inhibitors with IC50 values ranging from 0.1 to 2.6 -M, and that the S-S adducts are inactive.

Oct 1, 2003

By Duane L. Whiting

The National Environmental Policy Act of 1969 (NAPA) provides guidance for federal agencies in making informed decisions. The Act has been used to determine the potential environmental impacts from mining and other natural resource operations, primarily in the Western USA. To accomplish the purpose of the Act, a process for developing environmental documents was established. The documents (EA/EISs) evaluate environmental impacts and are produced by federal agencies through public participation and cooperating agency review. Effective interactions and up front coordination between agencies and industry is required. An abbreviated history of environmental protection in the USA leading to NEPA, the driving regulation, objectives, provisions and limitations of the Act, and select mining related NEPA projects III the Western U.S. are discussed in this paper.

Jan 1, 1998

By Thomas G. Chapman

The four major steps in the production of marketable copper are mining, concentrating, smelting, and refining. In a few cases, however, leaching takes the place of concentrating, smelting, and refining, and in others ores are smelted without being concentrated. Copper ores have been milled since the early days of mining in the United States. Except in the Michigan district, most copper ores went direct to the smelter until the so-called porphyry mines were developed. At present, although considerable leaching and direct-smelting ores are produced, the bulk of the copper ore mined is concentrated. Improved methods of concentration have kept pace with the increased tonnages of ores milled.

Jan 1, 1936

By Robert A. Cummings

A rock mass classification system has been developed for recommending drift support requirements in block caving mines. This development follows a two-year program incorporating field observations of support practice and performance in rocks of different classes, at several U. S. block caving mines. Popular rock mass classification systems presently in use for tunneling were applied at the various field sites; and were evaluated for conformance with caving mine support requirements and for general utility to caving mine operations. The developed system (MBR System) accepts readily-obtainable engineering and geologic data to yield a rational estimate of support requirements. The background and development of the MBR system is described in this report (Volume I). The use of the system is given in the Manual, a separate volume (Volume II).

Jan 1, 1984

By P. Nicholls

Patent records show that the idea that the burning of fuels can be improved by mixing or pretreating them with chemicals 6 dates back to the early years of the last century. By 1845, English and French patents included the specific beneficiations of elimination or reduction of smoke, soot, and clinker; reduction of the ashes, presumably meaning the total weight of refuse from the ashpit; elimination of sulphur fumes; increase in the rate of burning; increase in the time a given charge of fuel would last; and, in most patents, a saving of fuel. The earlier patents specified additions up to 80 pounds or more per ton of fuel, but after 1860 the quantity was rarely more than 4 pounds. There is no record of the extent to which these patents were commercialized, but after 1884 many American patents were assigned to companies specializing in treatment of coal, so it is probable that the products were marketed on a considerable scale at least as early as that date. From 1900 on, many companies marketed proprietary products that were sold under the general name of "fuel savers." Since its establishment in 1910, the Bureau of Mines has continually received inquiries about these products and, at the request of other govern-mental departments, has tested some used in accordance with the instructions of the purveyors; the results were all negative and, within the accuracy of measurements, the products had no effect on the burning.

Jan 1, 1937

By Edwin Higgins

SINCE the "Days of Forty-nine" California has been the premier gold producing state of the union. The greatest production was recorded in 1.852, during which year the state's placer and lode deposits yielded over 81 millions. This peak was followed by a steady decline to about 12 millions during the years 1888 to 189.3, a period marked by the cessation of gravel mining. After 1893, production increased to a new peak of over 22 million in 1915, thereafter decreasing steadily to something over 13 million in 1923. Today; California's gold production shows a decrease of 84 per cent. as compared with the output of 1852, and a decrease of 41 per cent, as compared with 1915. It is not a difficult matter to find the causes of this more recent decline. In 1916 there began an upward swing in the cost of labor, which represents approximately 60 per cent. of the cost of mining, and in the price of supplies, representing the remaining, 40 per cent. This rise continued until 1922 and since that year there has been no decided tendency either upward or downward. The increase in the cost of mining since 1916 is variously estimated at from 50 to 75 per cent.; the price of gold has remained fixed at $20.67 per oz. This condition resulted in wiping out the profits of the low-grade operations which, in recent years, have constituted California's main source of supply of gold ore. It is now predicted that there will be renewed activity in California- gold mining. What are chances for the materialization of this forecast? A boom or even a revival of gold mining must of necessity be brought about or accompanied by one or more of the following factors: 1. A decrease in the cost of mining. 2. An increase in the price of gold. 3. New capital for development. 4. The discovery of new deposits. 5. The revival of hydraulic mining.

Jan 1, 1925

By Don M. Coulter

"INTRODUCTION The Lookout Mountain coal deposits were examined by J.L. Stratton, an engineer of the Bureau of Mines in April and May 1943. The area investigated includes that part of southern Lookout Mountain in townships 4 to 8, south, ranges-9 to 11 east, and contains approximately 140 square miles in DeKalb and Cherokee Counties in northeastern Alabama (fig. 1.)Six coal seams having a minable thickness of 18 or more inches are represented in the area. The third seam, known locally as the Hill seam, has been correlated with the Upper Cliff No.1 seam and is referred to as such throughout this report. The preliminary investigation indicated that the Upper Cliff No. 1 seam is a low-volatile, high-grade coking coal. The work done on this project was confined principally to determining the amount and grade of coal in this seam.The only existing maps of mines in the area were one of the Lookout Fuel Co. at Lahusage, Ala. (fig. 2), and one of the Lookout Mountain Iron Co. at Battelle, Ala. (fig. 3), Consequently, to gain some knowledge of the grade and tonnage mined, surveys of the other mines were necessary. Many of them were caved, and many were filled with water, necessitating considerable preliminary work."

Feb 1, 1947

By E. A. Mevissen

With the ever increasing consumption of mineral commodities, the vital question is not whether sufficient mineral quantities will be available, but rather can the known existing low grade resources be mined economically. Conventional conveyor systems are being used in some open pit mines to decrease haulage costs. n an effort, to take this concept one stop further, this contract study examines the use of a high angle conveying system in an open pit mine. It identifies available high angle conveying equipment and examines the haulage and crushing costs associated with both a conventional truck and shovel mining operation and a high angle conveyor operation. These costs analyses were performed on a hypothetical copper, taconite and phosphate mine. Information was gathered from a series of high angle conveying equipment and open pit mining operations in the U.S. Volume I includes a detailed review of the state-of-the-art in high angle conveying concepts, the, hypothetical mine development, and the cost analyses. Volume II includes the appendices.

Jan 1, 1981

By John H. Johnson

This report covers the third and final year of work conducted under U. S. Bureau of Mines Grant G0166027, "Monitoring of Mine Air Pollutants". The report discusses work performed in three areas. These are the White Pine Mine (WPM) Experimental Unit, diesel mine-vehicle tailpipe emissions monitoring, and mine ambient air concentration data analysis. The WPM experimental unit was used to study diesel exhaust stratification in an 80 foot long dead-end heading while loading ore with a Wagner ST-5D scoop train LHD. The MTU Mine Air Monitoring Laboratory (MAML) was used to gather temperature and CO2 concentration data at 10 locations. Three different ventilation conditions were compared. The data substantiate the presence of strong buoyant forces of the hot exhaust gases which result in temperature stratification in dead-end headings. The diesel mine-vehicle tailpipe emissions monitoring study involved laboratory measurements of diesel undiluted exhaust pollutant concentrations by the portable tailpipe emissions measurement apparatus (EMA) assembled for in-mine use. The results were compared with simultaneous measurements by standard laboratory exhaust monitoring instruments. These results indicate that accurate field source quality control measurements can be obtained for CO2, CO and NO but NO2 results were low for all engine conditions. The mine ambient air concentration data analysis study included analysis of diesel pollutant concentration data in the Orchard Valley Mine air and comparison of the results with data collected earlier in the White Pine and Brushy Creek mines. The analysis included preparation of lognormal frequency distributions and calculations of C02-based concentration ratios and correlations. In the three mines compared, pollutant concentrations are distributed quite similarly, and the concentrations appear to be controlled to present standards.

Jan 1, 1979

INTRODUCTION The pager phones used in many underground coal mines are battery- operated, party-line telephones with provisions for loudspeaker paging. The system is two-wire, non-polarized, and is operated by self-contained batteries. Many of the individual units are certified as permissible. Requirements for installation are specified in state and federal regulations, such as in the Code of Federal Regulations, Title 30, Mineral Resources, Part 75. The major federal regulations that affect communication in coal mines are noted below, with a brief description of the subject matter in each of the relevant paragraphs. Refer to the cited paragraphs of Title 30 for explicit details of these regulations. (This brief description is for reference purposes only.) Minimum Requirements (paragraphs 75.1600, 75.17 13-2, and 75.1003-1) Approved telephone or two-way communication will be provided between the surface and each main shaft landing and each working section ; to the nearest medical assistance; and shall be protected from contact with trolley wires or trolley feeder wires. Installation Requirements (paragraphs 75.5 16-2, 75.52 1, and 77.508-1 ) Communication wires will be supported on insulated hangers, attached to messenger cables, or buried, to protect against mechanical damage ; installed opposite trolley wires; and insulated near power conductors . . . each cable will have lightning arresters within 100 feet of going below ground . . . and arresters will be provided wherever telephone wires enter a building. Wire and Cable Requirements (paragraphs 75.5 16-2, 75.5 17, and 75.52 1) Communication cable means two or more insulated conductors, covered by an additional abrasion-resistant covering; power wires and cables shall be adequately insulated and fully protected; and lightning arresters shall be connected to low-resistance grounds, more than 25 feet from neutral grounds.

Apr 1, 1975

By Robert S. Sanford, Harold C. Pierce

"At one time the Alaskan Eskimo lived in many small settlements scattered along the Arctic coast. These settlements extended as far south as Bristol Bay and several miles inland on the large rivers. When the white man established trading posts, schools, hospitals, and missions, these people gradually congregated around them in a few large villages. The natural fuel supply near many of the large villages along the Arctic coast became exhausted as a result of the abnormally large influx of people from small outlying settlements.The population of Barrow, Alaska, according to the 1940 census, is 363 persons, but since that time it has increased considerably, and later estimates place the present population between 400 and 500 persons. With the exception of 25 white persons, the entire population is comprised of Eskimos.The government maintains a school, hospital, radio station, and weather station at Barrow. In addition to the government, installations, there is a church, a privately owned trading post, and cooperative store owned by the Eskimos.For many years the Barrow Eskimos depended on driftwood and petroleum residue from Cape Simpson for their fuel supply. This fuel provided not only warmth for the Eskimo during the long cold winters but also heat for melting ice, the only source of 'water during .the winter. In recent years the sources of petroleum residue and driftwood have not been adequate to meet the demands for fuel During the winter of 1942-43 and again in 1943-44, Barrow experienced an acute shortage of fuel.The fuel problem at Barrow was brought to the attention of Governor Ernest E. Gruening, who was instrumental in getting a Bureau of Mines engineer4/ to investigate reported coal occurrences in the vicinity. Coal deposits along the Meade River and at Peard Bay were examined during the spring and fall of 1943. The Alaska Native Service shipped in mining equipment in September 1943 and commenced stripping an open-pit mine on the Meade River in June 1944. In conjunction with this work, an engineer5/ of the Bureau explored by churn drilling to determine the tonnage of- coal in the vicinity of the mine. In addition to this work, the Bureau of mines examined coal deposits in Peard Bay area and along the Kuk River south of Wainwright."

Nov 1, 1924

By R. Gallinger, B. Kelley

"In 1997, a group of Canadian mining companies met to review the Mine Environment Neutral Drainage (MEND) program and to consider future activities. They concluded that (1) that Canadian industry and Natural Resources Canada (NRCan) should fund a small secretariat in Ottawa to support technology transfer in Canada and, (2) that it was important for industry to continue the momentum of MEND on an international scale.The need for the International Network for Acid Prevention (INAP) was strongly endorsed by consultants, company, university, and government experts from Australia, Canada, and the United States who convened in Vancouver in February 1998. The initial focus was the development of a solid knowledge base covering the collective experience of INAP’s members to promote the dissemination of successful practices, the identification of knowledge gaps, and the formulation of effective research proposals. The sharing of information on past successes and failures alone was viewed assufficient justification for the formation of INAP.INAP was officially launched in October 1998, and is now an effective, industry-based initiative to globally coordinate research and development in the management of sulphide mine waste. Significant improvements in the management of sulphidic mine materials through knowledge sharing, research, and development of technology by INAP will reduce liability associated with acid drainage.This paper will explore the international efforts and activities of INAP."

Jan 1, 2005

By R. Curtis

To achieve compliance with 2015 EPA Tier 4 Final regulations, which permit only around 10% of Tier 3 particulate matter (PM) and NOx emissions, a number of technologies are being implemented. Use of a fuel borne nanoparticle combustion catalyst reduces the level of PM and unburned hydrocarbons exiting the combustion chamber, alleviating the burden on downstream exhaust after-treatment systems. The impact of an iron-ceria combustion catalyst (GO2) on carbon oxidation kinetics and on diesel engine emissions is presented. The iron-ceria nanoparticles catalyze carbon oxidation at lower temperatures and increase the oxidation rate by a factor of 18 at 400 °C. Engine tests on a generator powered by a John Deere Model engine and field tests on a Cummins ISC 330 tractor truck and CAT 3508B propulsion engines are presented. Use of GO2 resulted in a reduction in PM10 (particulate matter under 10 um) emissions of up to 26% and a hydrocarbon emission reduction of up to 41%. NOx emissions did not increase in these trials and the amount of change depended on engine type. Application of this fuel borne technology for emissions reductions in mining equipment offers significant benefits.

Feb 27, 2013

By V. K. Srivastava, T. Gupta, T. Ghosh

"In recent years, the demand for rare earth elements (REEs) has grown due to increasing demand and global supply shortage. The supply deficit of these critical elements has encouraged the search for new sources, with coal and coal byproducts as possibilities. Coals from certain parts of the world can be rich in REEs and can approach a total concentration of 1,000 ppm. Two Alaskan coal samples, from Healy and Wishbone Hill, were investigated for the effects of density and particle size on REE concentrations for three selected size fractions, and flotation tests were conducted on finer fractions. Additionally, bottom ash and fly ash samples from a power plant were examined for their REE concentrations. The results show that the upgrade potential for REEs on an ash basis from a whole-coal basis ranges from 2:1 for the Wishbone Hill samples to 4:1 for the Healy coal samples. Flotations of the finer fractions of the two coal samples, conducted under similar conditions, revealed higher concentrations of REEs in the tailings. Both coal samples had comparatively higher contents of light-group rare earth elements (LREEs) than heavy-group rare earth elements (HREEs). REE content trends for the power-plant products on an ash basis indicate that fly ash has slightly higher concentrations of both LREEs and HREEs than bottom ash. IntroductionRare earth elements (REEs), also known as rare earth metals, and their compounds are vital components in industrial, automotive, petrochemical, defense and medical applications. Dysprosium in combination with other elements is used in laser materials and nuclear control applications. Neodymium is present in magnets that are used in the manufacture of wind turbines and hybrid cars. Europium, terbium and yttrium are used in devices that have visual displays such as computer screens and laptops (Haxel, Hedrick and Greta, 2002; Bunzli, 2013). REEs pose fewer environmental problems of disposal and recycling than their conventional heavy metal counterparts (Haxel, Hedrick and Greta, 2002). They are key materials for radar systems, avionics, modern national defense and satellites (Cammarata and Sieradzki, 1994; Hedrick, 2010; Martin, 2010; Szumigala and Werdon, 2011; Cordier, 2011; Bunzli, 2013). REEs are often classified into light-group rare earth elements (LREEs) and heavy-group rare earth elements (HREEs). This classification is primarily based on the electronic configuration in the outermost shell. LREEs, ranging from lanthanum to gadolinium, have a single or no spinning electron in the outermost 4f shell while HREEs, ranging from terbium to lutetium, have paired electrons in the 4f shell. This difference in electronic configuration is responsible for the differences in physical and chemical properties of REEs."

Jan 1, 2017

By Jack M. Campbell

The regulatory process by which governmental authorities acknowledge and, in turn, permit the location, construction, and operation of large scale energy-related facilities has become extremely detailed in recent years. One example of the detail that is entailed in the regulatory process is the number of permits that must be acquired by operators prior to the construction and operation of energy-related facilities. It has been estimated, for example, that 75 permits are required prior to the opening of a new coal mine in Pennsylvania while 50 are required in Kentucky. From the perspective of facility owners and operators the regulatory process often appears overly complex and may be perceived as a constraint to the corporate decision making process. From the perspective of those responsible for administering regulations, the process is perceived as a mans by which public desires - pursuant to social objectives such as environmental protection and occupational safety - can be achieved. As a result of conflicting organizational interests, the clash between energy facility owners and operators and their regulators appears to be inevitable. Furthermore, the resolution of this conflict lies in the tradeoff between objectives and the costs of regulation. The balance of objectives and costs is a subject of the political process and not a topic of consideration in this paper. This paper is concerned with the actual administration of regulations, that is, the implementation of that which arises from the interplay of organizational interests. The paper assumes that environmental control laws will not likely be repealed, that regulations to implement the intent of these laws are here to stay and thus the paper seeks to assess how regulations are administered at various levels of government pursuant to objectives. The paper hypothesizes that the administration of objectives (or policy) has an impact on decision making which affects energy facility decision; making while recognizing the fact that regulatory policy cannot be totally divorced from administration, this paper proceeds

Jan 1, 1977

By N. Shariatmadari

In recent years, determining bearing capacity of piles from in-situ testing data as a complement of static and dynamic analysis has been used by geotechnical engineers. In this paper, different approaches for estimating base bearing capacity of piles from SPT data has been compared and evaluated. A new method for pile base bearing capacity in sand is proposed using SPT records. Data averaging, failure zone extension, and plunging failure of piles have been addressed in the proposed approach. A data bank comprising 10 full scale static load tests on instrumented piles and 26 dynamic tests, analyzed with signal matching technique by CAPWAP software, was used for validation. The SPT data that was performed close to pile locations is also included in the data base. Comparison of current methods by error investigation with Log-Normal approach demonstrates that the proposed method predicts pile base capacity with more accuracy and less scatter in comparison to other methods.

Jan 1, 2006

By J. Thompson

Paper written on project work carried out in partial fulfilment of B. Eng (Mining Engineering) degree A study into the stability of strike gullies at TauTona mine was to be carried out. In reaching the conclusions to follow, a three-stage process was followed. ?A literature study as well as discussions with management and workers alike to gain their inputs and perceptions. ?An ESH Department survey into the history of transgression from proper mine standard in TauTona strike gullies. Unfortunately records were found to be scarce and obscure and the importance of better inter-departmental recordings cannot be stressed enough. ?An underground survey of 11 pre-selected gullies distributed in both the UCL and LCL reef horizons. This stage is to carry the greatest weight in the points to be brought forward in this report. The process highlighted and ranked the following areas as the most critical role players in the deterioration of strike gullies: ?Poor blasting practice ?Sub-standard siding depth and lead-lags ?Split sets ?Off line gully development ?Adverse geological features. The following has been suggested to the mine to help reduce strike gully instability. ?Where possible, maintain lead-lags below 7 m?else increase the siding depth to suit. ?Decrease the gully width standard to 1.2 m (especially in ?high risk areas?). ?Discourage drillers from drilling side holes in gully face blast pattern. This will allow for time in which tendon support can be kept up to date. ?Ensure split sets are installed 1 m behind the gully face so as to prevent opening up of fractures. ?Utilize the centre split set in the 1:2:1 pattern to maintain the proper gully line. ?When adverse conditions prevail, it is necessary to apply a special support plan not only to the panel face, but also (just as importantly) to the gully as well. Shotcreting of the gully hanging is a suitable long-term consideration for providing the additional a real coverage needed. List of Abbreviations [CL Carbon Leader M/O Mine Overseer UCL Upper Carbon Leader FOG Fall of Ground LCL Lower Carbon Leader H/W Hanging Wall ERR Energy Release Rate F/W Foot Wall WDL Western Deep Levels ESH Environmental Safety and Health ]

Jan 1, 2002