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By A. C. Fieldner

Much activity is called for in the present period of hightened national effort, and wise direction of such a program must always be conditioned by positive knowledge gained in years of slow and painstaking study and development. Research and technologic investigations on coal by the Bureau of Mines have been described in a series of annual

Jan 1, 1941

By F. W. Gray

Summarized Foreword This paper is one of a series arranged by Institute Divisional Committees for the Fiftieth Anniversary Meeting, reviewing the experience of the major mining and metallurgical industries during the life of the Institute. The viewpoint is national and broadly technical. Geology is stressed on a continental scale without regard for provincial boundaries. The boundary between Canada and the United States is, however, so decisive a factor in our coal-mining economics and our political evolution that mention of its implications cannot be avoided. The Laurentian Shield in Canada makes the occurrence of coal deposits a geological impossibility between the St. Lawrence Lowlands and the Great Plains. All but five per cent of Canadian coal resources occur west of Winnipeg. The utilization of this ninety-five per cent of our coal wealth has to date been a consequence of transcontinental railways' development, and the small fuel needs of thinly populated wheat farming and cattle-raising territory, in what- to judge from the development of mixed farming and greater population density of Manitoba- is merely an initial stage of agricultural intensification and accordant population growth. There is no useful purpose in measuring coal resource against consumption rate in the West as a whole, because the resource is but partially known, and it is difficult to believe that industrialism based upon coal utilization is in any but its infant stage of growth. Canada west of Winnipeg possesses, moreover resources of petroleum and natural gas, which, together with the power-potential in the long watershed of the eastern slope of the Rocky mountains, give to population centres such as Calgary and Edmonton a choice of energy resources that is almost an embarrass des riches.

Jan 1, 1948

By J Joy, A Bye, G V. Kizil

This paper demonstrates an application of a recently developed Risk-Cost-Benefit (RCB) Framework to environmental risk management in the mining industry. The environmental application of the RCB Framework as part of an ACARP project (Kizil, Bye and Joy, 2012) involved a thorough selection process with site visits and in-depth discussions with the case study siteÆs environmental management team. Under their guidance, the highest risk of environmental impact at the case study site was identified as æroad subsidenceÆ at the time when the project work was undertaken. This paper presents the unique application of the RCB Framework to examine the risk of mining-induced subsidence and its impact on one of AustraliaÆs busiest highways, with a traffic volume of 38 000 vehicles per day (NSW RTA AADT, 2008). The RCB Framework was employed to assess the optimum group of controls for road subsidence risk management to ensure highway availability while mining occurs. Whilst this paper focuses on road subsidence, the methodology employed can be directly applied to other environmental concerns including preparation for mine closure, rehabilitation planning and waste management. The RCB Framework incorporates mathematical modules which were developed to enable complex yet tightly integrated RCB calculations. The process integrates the risk-control effectiveness assessment to determine that the selected safety initiative is financially beneficial to the mine site and company. This concept has been applied to a number of high-risk mining areas targeting safety, productivity and environmental issues. This paper introduces the five-staged RCB Framework, incorporating the RCB tools RCBGEN (Risk-Cost-Benefit Generator) and RCEMETHOD (Risk-Control-Effectiveness Method), and demonstrates its practical application to the risk management of a road subsidence case study. The case study looks at potential pavement damages, in particular, the occurrence of pavement stepping on the surface of the highway as a result of vertical subsidence. This type of road damage was previously experienced at another major inter-city route while underground mining occurred in the region where the case study site is located. The RCB Framework has been successfully applied to the analysis of the road subsidence case study and determined the risk reduction and financial benefits of implementing a range of risk-controls. User-friendly RCB Charts to provide an aid for decision-making were produced. The value of using the RCB charts to achieve balance between risk, cost and productivity in the decision-making process for risk management has been explained. The case study determined that pavement slots and fibre-optic cable monitoring were relatively low-cost and effective controls applied in the mining industry for the first time at a global level.This paper supports the industryÆs ongoing efforts to manage risk to ALARP (as low as reasonably practicable) and achieve æzero harmÆ by providing a new Framework to more effectively establish the adequacy of controls.CITATION:Kizil, G V, Bye, A and Joy, J, 2012. Application of risk-cost-benefit analysis to highway subsidence due to mining, in Proceedings Life-of-Mine 2012 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Dirección General de Promoción y Sostenibilidad Minera del Ministerio de Energía y Minas

El artículo da cuenta de la situación del sector al 2019, año en el que pese al panorama adverso se superó la meta de inversiones con más de US$ 6 100 millones ejecutados. Se reportan asimismo las importantes mejoras efectuadas en la normativa minera para actividades de exploración, como son —entre otras— la ampliación por 3 años de la vigencia de la Ley N° 27623 y el adelanto de inicio del proceso de consulta previa para actividades de exploración. El artículo incluye la nueva cartera y el Mapa de Proyectos de Exploración Minera, actualizados a febrero 2020.

Feb 28, 2020

By J B. Magee

Sheep Creek Mines Limited has developed several operating techniques that have greatly assisted in keeping unit costs at reasonable levels. Some of the techniques, as described in this paper, include organization, accounting, warehousing, bonus and contracts. INTRODUCTION THIS paper is a non-technical report on operating techniques developed by Sheep Creek Mines Limited at their Mineral King mine, located near lnvermere, B.C. Depressed metal prices and continually rising labour and materials costs have necessitated a continuous search for method to keep operating costs down. The newly developed techniques and practices have greatly assisted in maintaining unit costs. Sheep Creek Mines Limited is a mining company incorporated under the laws of the Province of British Columbia. The Company's share capital is 3,500,000 common shares, witl1 a par value of 50 cents each, of which there are 1,875 000 shares is-sued. The Company has eight di-rectors. The administration, exploration and accounting offices are located in Nelson, B.C. The Company's working capital is approximately $1,500,000.

Jan 1, 1963

By A. Hekmatnejad

"The objective of this work is to validate a methodology for spatially predicting the fracture intensity, defined as the average fracture area per unit volume. First, using the observations from drill holes, the fracture intensity is directly inferred at the support of drill-hole composites based on a Terzaghi correction. Subsequently, the composite values are interpolated to larger blocks. The methodology is tested on sets of simulated fracture networks, in which each fracture consists of a disc with a random diameter, random position and random orientation. For each of these simulated networks, one can calculate the actual fracture intensity within any region of space, based on geometric considerations. A regular sampling mesh is then defined to emulate a set of vertical drill holes and the proposed methodology is applied to predict the fracture intensity, both globally and locally. The actual and predicted fracture intensities are finally compared, showing that predictions are unbiased, insofar as, on average, the prediction error is always close to zero. Also, the error dispersion increases when the support of the prediction decreases, which is consistent with the well-known support effect. In practice, the proposed methodology allows predicting fracture intensity based exclusively on drill-hole information, without the need for simulating fracture networks in space, hence its interest. INTRODUCTION The characterization of fractures in rock masses is an important part in the evaluation of mechanical and hydraulic properties of rocks. Fractures have a large impact in disciplines such as reservoir engineering, safety of underground storage of CO2 or of nuclear waste, assessment of high-enthalpy geothermal installations, safety of mining exploitations, efficiency of in-situ leaching operations or of extraction by block-caving. As a rock mass property, fractures must be characterized in the three-dimensional space, whereas observations are limited to 1D (drill holes) and 2D (outcrops, drift walls), moreover very often to rather short stations, so that the available data are subject to geometric bias, truncation and censoring. Fracture characteristics includes the number of fracture sets and, for each set, the number, orientation, spacing, location, shape and size of the fractures must be inferred from data sampling. Some important parameters that are considered nearly in all models are fracture intensity and fracture size."

Jan 1, 2016

By A E. Annels, G F. Johansen, B W. Cuffley

Nuggety gold-quartz reefs are characterised by localised, high-grades and in many cases coarse free-gold. Geometrical and grade complexities are often observed. The high-grade regions are generally erratic and have a low continuity; though may make the deposit economic. Viable grades are generally contained within discrete oreshoots, which are surrounded by barren/low-grade material. Drilling is an effective measure of geological continuity, however grade distribution can only be reliably obtained from underground development and bulk sampling. In general terms, only an inferred resource is likely to be estimated from surface drill data alone. Underground development, further drilling and probably bulk sampling will be required to delineate inferred and indicated resources. Closely spaced development with bulk sampling is likely to be the best way to determine a probable reserve. The resource evaluation process must driven by a clear geological model that should attempt to understand the controls to reef geometry and grade distribution. Geological interpretation has traditionally been undertaken in two-dimensions, though computer software is now being used to produce three-dimensional models. Grade interpolation has generally been undertaken using classical methods, typically weighted averages, zone of influence weighting and polygonal/sectional blocks. Tonnages can generally be calculated from diamond drill and development information with a reasonable degree of confidence. Grade is much more difficult to define with confidence because of its highly erratic and discontinuous nature. To account for variability it is recommended that a best estimate be reported within a grade range, as this more accurately reflects the uncertainties involved. Reporting should be undertaken within the framework of the JORC code, but should involve special consideration of grade reliability.

Jan 1, 2000

By R. W. Stahl

Coal mining has been revolutionized by the continuous miner. This machine has replaced, or has combined into 1, 3 former operations: Cutting, blasting, and loading. During the 25-year period before this machine was introduced, advances had been made in transportation, but the actual "coal getting" remained virtually the same. As frequently occurs, the multiple-purpose continuous miner introduced a new hazard--more rapid liberation of methane. The coal output formerly obtained from 10 to 20 working places might now be obtained from 1. It is true that circulation of air was generally increased; but the bulk of this machine virtually precludes continuous flow of air across the face, where gas may accumulate. Apprehension about this possible hazard led the Bureau of Mines to test face atmospheres during operation; and Report of Investigations 5288, Methane Buildup During Cutting and Continuous Mining Operations (published in 1956), presents proof that real danger may be present in many otherwise well ventilated mines.

Jan 1, 1958

By Karl J. C. Harries

"14.1. INTRODUCTION1The boilerplate of an agreement is not a single provision, but a series of provisions that are expected in “every agreement”. They are sometimes also referred to as the “lawyer’s provisions”. Many businessmen consider the boilerplate to be superfluous and, to some extent, window-dressing by the lawyers – even legalese. They will often offer advice to the effect that it can “pretty well be ignored”. Such advice could not be more wrong.Most boilerplate provisions are essential parts of every agreement. Some may be part of a “standard package” and may have little relevance to the agreement at hand, but these are the exception rather than the rule. The exceptions should not be treated as justification for giving all these provisions short shrift. The boilerplate should receive the same review, consideration, and negotiation as the provisions that set forth the business deal. It is often these provisions that make the deal work or that are turned to at the time of disputes. If they are inadequate, as they sometimes are (unfortunately, some draftsmen are also loath to review or update their standard boilerplate provisions or to tailor them to the deal at hand), they can create problems, rather than offer solutions. Such problems can be costly and time-consuming for the parties to address. Inadequate or incomplete provisions may ultimately be one of the reasons for the parties to turn to the courts to settle their differences. On the other hand, good boilerplate provisions can help keep them out of the courts.One of the principal objectives of an agreement should be to provide procedures, or mechanics, for implementing agreed principles and for the parties to follow to settle their differences, real or perceived, without going to the expense and disruption of a lawsuit. An agreement should aim to keep the parties away from the courts, not serve as a springboard to the courts. It must nevertheless be acknowledged that, if there is a major falling-out among the parties to an agreement, the chances are that, however carefully the provisions of that agreement have been negotiated and drafted, the parties will end up before the courts or some other adjudicating body."

Jan 1, 2003

By M Olsson, U Nyberg, K Widenberg, P Svedensten, F Ouchterlony

During 2007 and 2008, the project Optimal Fragmentation in Blasting II was conducted at the Långåsen quarry of NCC Roads AB near Arlanda. The main goals were:an evaluation of the effect of using electronic delay detonators (EDDs) in quarry blastinga validation of the design curve concept introduced at the Vändle quarry.Five production blasts were monitored. After a first trial round, the remaining four rounds each had about 100 Ø89 mm holes in a 14–19 m high bench charged with site mixed emulsions. In rounds 1 and 2, a tighter pattern than normal was used in one half of the rounds, raising the specific charge there from 0.7 to 1.0 kg/m3. Non-electric initiation was used with two holes per 25 ms delay in-row and 67 ms between rows. In rounds 3 and 4, electronic delay detonators were used instead, with 10 and 5 ms in-row delays respectively.The monitoring encompassed drill hole collaring and alignment, in-hole deviations, the rock structure in the bench faces from 3D imaging, first row burdens, etc. Eleven 400 t samples were taken from the muck piles and sorted in the quarry and sieved in the laboratory (lab). The lab data made up a fines tail that was grafted onto the in-pit sorting data to form sieving curves for the test piles. These curves were then compensated for the absence of boulders to construct the sieving curves for the blasted muck pile.These have been used to derive fragmentation model formulas for the non-electric rounds, also called design formulas. They are based on blast geometry, charging data and the properties of the rock mass. The formulas may be used to estimate the effect of changing blasthole pattern, borehole diameter and stemming length for example.The use of EDDs gave several unexpected results. In comparison with non-electric initiated rounds with a somewhat lower specific charge the fragmentation was much coarser; x50 increased from 160 to 200 mm. The effect of raising the specific charge in the non-electric initiated rounds from 0.72 to 0.99 kg/m3 was a much finer fragmentation; x50 decreased from 160 to 120 mm.CITATION:Ouchterlony, F, Nyberg, U, Olsson, M, Widenberg, K and Svedensten, P, 2015. Effects of specific charge and electronic delay detonators on fragmentation in an aggregate quarry – building fragmentation model design curves, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 727–740 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By C. G. Anderson

Throughout the world, there are many orebodies or materials which have significant value but also contain arsenic. As regulations on the transport, exposure, disposition and emission of arsenic have become more stringent; it has become increasingly more difficult to derive the values from these resources. This paper will outline the fundamentals of alkaline sulfide hydrometallurgy and its successful application to arsenic bearing ores, concentrates and materials.

Jan 1, 2005

By C McCamley

"The requisite for maintaining optimal carbon concentration levels in a carbon-in-leach (CIL) circuit is of paramount importance in the prevention of gold losses. The process’s ability to recover gold from the aqueous phase is primarily dependent on the carbon loading profile of the CIL train.Newmont Boddington Gold (NBG) have over 2015 tested the Mintek online carbon concentration wmeter (C2 Meter) suitability for effective carbon concentration measurements in their CIL circuit compared to the standard method where the readings are taken twice a shift by the operations staff. The C2 meter works by passing a 1MHz ultrasonic signal through a slurry containing carbon where there is a relationship between the carbon concentration and the attenuation of that signal.It also highlighted another area where the C2 meter could be implemented at NBG whereby the instrument can be as a cautionary device for carbon losses in place of carbon safety screens.Citation:McCamley, C, 2016. Continuous Carbon Concentration Measurement at Newmont Boddington Gold, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 207–212 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By J. D. Sargent

Selenium might be described as a paradoxical element, being either a metal or a nonmetal, a conductor or nonconductor, amorphous or crystalline, colorant or decolorant, and a hydrogenator or dehydrogenator. Selenium was discovered in 1817 by the Swedish chemist, Berzelius, while studying flue dust from the lead chambers of the sulfuric acid works at Gripsholm, Sweden, The ordinary stable form of selenium is a crystalline, grayish solid with semi-metallic luster. It melts at 217° C., boils at 684.8° C., and has a density of 4.79.

Jan 1, 1955

By R. P. Tavares, M. Isac, R. I. L. Guthrie

"The configuration of the metal delivery system used in twin-roll casting can play a significant role in determining both internal and surface quality of the strips produced by this process.In the present work, a mathematical model for coupled turbulent fluid flow, heat transfer and solidification was developed and used in the study of metal delivery systems for twin-roll casting of low-carbon steels. This study was applied to a pilot twin-roll caster being investigated in Canada, with a roll radius of 0.3 m, producing strips of thicknesses from 4 to 7 mm, at roll speeds ranging between 4 and 12 m/min. Various configurations of metal delivery systems were simulated and their effects on the advance of the interdendritic solidification front and levels of turbulence and temperature within the caster investigated. According to the predictions of the model, an extended nozzle with inlet flow towards the surface of the rolls seems to be the best alternative for feeding liquid steel into twin-roll casters.A full scale water model of a pilot twin-roll caster was also built and used to qualitatively validate the predictions of the mathematical model.Various techniques for fluid flowvisualization were applied. In general, the predictions of the mathematical model were in reasonable agreement with the experiments with the water model."

Jan 1, 1999

By J. R. Schafler, J. L. Brinkman

"Since the year 2000, 59 miners have lost their lives to explosions occurring in underground coal mines in the US. More accurately, those explosions were methane ignitions that propagated through the mines due to coal dust involvement; despite current explosion prevention standards. There are 4 basic strategies employed to manage the risk of coal dust explosions in many other coal mining countries around the world: removal of the coal dust, wetting of the coal dust to prevent it from becoming airborne, mixing of the coal dust with stone dust to increase the total incombustible content, and explosion activated barriers which make the entire roadway inert. However, American standards only mandate the first 3 of these 4 methods. It is possible that US coal mine safety measures could benefit from the implementation of the 4th method, the use of explosion barriers. This paper will discuss differences/similarities in barrier regulations used in other countries, as well as some potential difficulties with adapting a stone dust bag barrier system to US underground coal mines. Also, details and feedback gathered from two operating mine site trial barrier installations will be shared.INTRODUCTION Since the year 2000, 59 miners have lost their lives to explosions occurring in underground coal mines in the United States (US); 29 miners were killed at the Upper Big Branch mine in 2010, 5 at the Darby Mine No. 1 in 2006, 12 at the Sago Mine also in 2006, and 13 at the Jim Walter No. 5 Mine in 2001.[14] To be more accurate, the explosions that killed those miners were methane ignitions that propagated through the mines due to coal dust involvement.[18, 19, 20, 21] These deaths occurred despite current explosion prevention strategies, standards, and regulatory oversight. This poses the question, can more be done in the US to prevent coal dust explosions and their widespread damage. In review of current practices and regulations from several large coal mining countries, a disparity in prevention strategies arose. The main difference between the US and other countries was that the US does not encourage, mandate, or regulate the use of explosion barrier systems as an additional coal dust explosion mitigation measure. This raised many questions. First and foremost was whether or not the US coal mining industry and its miners could benefit, in terms of safety and fatality prevention, from the implementation of the explosion barrier systems that are used in other countries. Furthermore, are there significant differences between the coal mines in countries where explosion barriers are used and US coal mines, which would preclude the system from being adapted and implemented in the US? Also, what are the similarities and differences in explosion barrier systems, use, and regulations between other countries that use them?"

Jan 1, 2017

By D. S. Yantek, R. J. Matetic, A. K. Smith, E. D. Thimons, J. Srednicki

In a 2007 report to the U.S. Congress, the Office of Mine Safety and Health Research of the U.S. National Institute for Occupational Safety and Health (NIOSH OMSHR) stated that built-in-place refuge alternatives (BIP RAs) provide significant advantages over mobile refuge alternatives. At present, the requirement to locate refuge alternatives within 305 m (1,000 ft) of working faces makes BIP RAs impractical in most coal mines. BIP RAs would be practical if three issues are addressed: (1) allowing BIP RAs to be located at greater distances from the working face, (2) developing a reliable process for the design and approval of BIP RA stoppings that meet the 0.1-MPa (15-psi) design criteria, and (3) developing systems that reliably deliver breathable air to the refuge alternative. In 2015, NIOSH OMSHR conducted a study of these three issues and issued a report. In the report, justification was provided for allowing the placement of BIP RAs at greater distances from the working face than the currently mandated 305 m (1,000 ft), guidelines were developed that could be used by industry when submitting BIP RA stopping design applications for approval which are patterned after the Mine Safety and Health Administration guidelines for coal mine seal design applications, and insights were provided into options for providing a reliable supply of clean, breathable air to BIP RAs. This paper presents a summary of the study’s findings and also addresses issues discovered during the building and designing of a BIP RA that OMSHR researchers constructed in NIOSH’s Experimental Coal Mine in Pittsburgh to research the testing and improving of BIP RAs. These issues include several issues related to the delivery, distribution and exhaust of ventilation air to the BIP RA and some general construction issues that require further investigation.

Jan 1, 2016

By L. C. IlsLey

The theory and practice followed by the Bureau of Mines in investigating electrical equipment4/ made for service in gassy mines are of particular interest not only to manufacturers but also to those organizations that deal with safety anal inspection at the mines. This publication purposes to discuss the theory upon which tests of equipment in explosive atmospheres are based and to consider inspection and other matters pertaining to investigations made by the Bureau in ascertaining whether a machine merits approval. The material in this report is taken from an earlier bulletin,5/ which is row out of print, and has been revised and brought up to date to make the information again available to manufacturers, inspectors, and others interested in the development of safe equipment.

Jan 1, 1954

By R. J. Fantel

The Bureau of Mines investigated the resource potential of 201 mines and deposits in 28 market economy countries and 17 mines and deposits in the U.S.S.R. and China. The 201 mines and deposits evaluated from market economy countries contain an estimated 34.2 billion metric tons of recoverable phosphate rock (at the demonstrated resource level), with Morocco and Western Sahara accounting for 61% (21 billion tons), followed by the United States with 19% (6.4 billion tons). The 17 mines and deposits evaluated in the U.S.S.R. and China contain approximately 1.5 billion tons of potentially recoverable phosphate rock. Potential annual capacity from low-cost, high-grade producing mines in the United States is estimated to decline significantly during the latter half of the next decade, and the United States will have to develop new, higher cost, lower grade mines in order to satisfy demand into the next century. Of the world's new production capacity which could likely be developed over the next decade, slightly over one-third could be produced at an estimated 1981 cost of $40 per ton or less, and about two-thirds would cost in the $40 to $50 range (including a 15% rate of return). In comparison, moot of the competing phosphate rock from producing mines in Morocco could be produced for under $40 per ton. The United States has sufficient demonstrated resources of phosphate rock (plus huge quantities at the identified and hypothetical resource levels) to satisfy domestic consumption for many years to come, but its future ability to compete in the major export markets against low-cost competitors is much more uncertain.

Jan 1, 1984

By Larry A. Haas

The Bureau of Mines constructed a torsion effusion apparatus to measure the equilibrium vapor pressure of pure metals, alloys, and compounds at temperatures up to 1,500° K. The reliability of the apparatus was established by determining the vapor pressure of silver. The data obtained on solid and liquid silver in the temperature range 1,200° to 1,500° K can be expressed by the following equations:

Jan 1, 1965

By W. J. Asselstine

Introduction This paper is prepared from data gathered for a similar paper to be submitted to the United States Bureau of Mines, for publication as one of their information circulars. It covers the history and development of the present milling practice at Premier. The authors wish to acknowledge the assistance and suggestions given during the preparation of this paper by D. L. Pitt, Manager of the Premier Gold Mining Company, Limited; also their indebtedness to various members of the Engineering Staff and of the Accounting Department who have assisted materially in gathering the data used. Location The Premier mine and mill are situated in northern British Columbia, approximately fifteen miles north of the head of Portland canal, in the Salmon River section, about half a mile east of the Alaska-British Columbia boundary line where it crosses die Salmon river. The mill is located on a rather steep hillside on the horizon of the main haulage level of the mine, and is within a hundred feet of the mouth of the tunnel. Both the mine and mill are connected with tidewater at Stewart, B.C., by an aerial tramway (1) eleven and one-half miles in length, which delivers both ore and concentrate to the bunkers at the dock for shipment to the smelters. All mine and mill supplies are transported from Stewart dock to Premier over this tramway, except heavy machinery. Heavy pieces have to be hauled either by truck in summer or sleighs in winter over a good road which runs from Stewart dock to Premier.

Jan 1, 1933