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By N. Aouad

Dump truck operators are exposed to whole-body vibration (WBV) levels that exceed the International Standard Organization (ISO) 2631-1. The WBV level measured by RMS acceleration value, for operator comfort, and long-term health and safety is under 0.315 m/s2 by these standards. However, fundamental research by Frimpong and Aouad (2009, 2012) and field experimental study by Kumar (1999) have shown that operators are exposed to extreme WBV levels exposing them to injuries and musculoskeletal diseases in the long-term. These extreme WBV values in the vertical direction are equal to 3.56 m/s2, 1.12 m/s2 and 0.87 m/s2 for the operator?s seat, lower-back and cervical regions, respectively. This paper will outline current research to solve these problems. Keywords: WBV, Truck Vibrations, MSC.ADAMS, Virtual Prototyping

Feb 27, 2013

By A. R. Leach

Anomalous mining conditions can be described where the level of hazard is increased relative to normal conditions within a mining area. Normal conditions would be those defined as a Ground Control District in a mine’s code of practice, and for which mine standard support layouts are generally developed. It has been found that up to 80% of fall of ground accidents occur where anomalous mining conditions exists, typically in the vicinity of geological weaknesses. These areas require specific attention to ensure they are readily anticipated and identified and that appropriate strategies are used to reduce the hazards associated with them. As part of SIMRAC project GAP 607 checklists to aid identification and best practice mining methods were identified for a range of geotechnically anomalous conditions.

Jan 1, 2003

By Robert L. Parsons

This paper describes the results of a detailed analysis of a loess deposit at the deep foundations test site established by the Kansas Department of Transportation. Multiple CPT, SPT, and pressuremeter tests were conducted as part of the investigation. This paper includes an evaluation of the effectiveness of common correlations used with the CPT, SPT when used for classification of loess and estimating its properties. Results show that common correlations must be used with caution as significant errors in estimation may result from using methods developed for other soil types. Laboratory testing included direct shear, triaxial, collapse, and consolidation testing, with many of the tests conducted on both vertically and horizontally oriented samples to evaluate anisotropic behavior. The results showed that strength properties could be considered to be isotropic.

Jan 1, 2009

By Richard I. Miller

Science Applications, Inc. has developed for the U.S. Bureau of Mines a rapid response radon monitor capable of accurately responding within three minutes to changing radon levels of magnitude from 100 to 10,000 pCi/1, typical of the levels in working uranium mines. The instrument weighs 17 pounds, is sized 12" x 10" x 6", and is capable of 8 hours of continuous portable operation with a self-contained, rechargeable battery power source. Residual chamber contamination from a radon level allowed to remain in the chamber for 90 minutes is about 10 percent, decaying about a factor of two in one hour. The instrument sensitivity is a nominal 0.1 cpm/(pCi/1), with a background count rate of less than 1 cpm.

Jan 1, 1979

Bioremediation of Acid Mine Water Using Fly Ash and Desulfotomaculum nigrificans One of the major concerns for the mining industry especially after the mine closure is the generation of acid mine drainage (AMD), and its discharge into the environment surrounding the abandoned mines, leading to serious environmental pollution. AMD is usually characterized by high concentration of dissolved metal ions, sulfate and low pH. The efficacy of fly ash was assessed for the removal of metal ions such as iron, zinc and copper as well as sulfate from synthetic acid mine water. Complete removal of ferric and ferrous, 80 per cent of Zn, 83 per cent of Cu and 62 per cent sulfate removal could be achieved, with a concomitant increase in the pH value from 2.3 to 7 using fly ash as an adsorbent under appropriate conditions. The free energy of adsorption of the metal ions onto fly ash was found to be negative, while the adsorption process was endothermic and adhered to the Lagergren pseudo-first order rate equation. Bioremediation studies using a typical sulfate reducing bacterium namely Desulfotomaculum nigrificans, after pre-treatment of the synthetic acid mine water with fly ash, cumulatively resulted in about 94 per cent zinc, 100 per cent copper and 90 per cent sulfate removal. The possible mechanisms of metal ion removal and sulfate reduction from acid mine water utilising Desulfotomaculum nigrificans are discussed.

Sep 13, 2010

By Michael S. Miller

In 1984, at the request of Bureau of Land Management, the Bureau of Mines studied 8,500 acres of the 20,250-acre Seven Blackfoot Wilderness Study Area (WSA) consisting of all 3,950 acres of MT-024-657A and 4,550 acres of the 4,850 acre MT-024-657B in order to evaluate the mineral resources. Within this report these 8,500 acres are referred to as the study area. Located about 30 miles northwest of Jordan, MT, the study area is underlain by outcrops of Quaternary alluvium and Cretaceous to Paleocene sandstones, shales, clays, and coal. No mines or prospects were found in the study area. Except for some current interest in petroleum and natural gas, there has been no mineral exploration activity in the study area. The study area contains subeconomic clay, placer gold, and coal. Land within the study area is leased or under lease application for oil and gas.

Jan 1, 1986

By Pedro Lilienfeld

This report presents a design and cost investigation for several alternative versions of a field-worthy mining machine-mounted respirable dust monitor. Three main design variations are considered: (a) light scattering sensing, (b) Beta-filter tape sensing, and (c) a combination of the two preceeding methods. Eventual instrument production coats as a function of design complexity are tabulated. Cost estimates for the development and field testing of field-worthy prototypes are also presented. A general discussion on the technical aspects of these design alternatives is included following a modular-hierarchical approach of progressive complexity. The technical background to this report has been provided by the experience and results derived from the work performed under U.S. Bureau of Mines Contracts Nos. H0166097 and H0377092.

Jan 1, 1980

By V Barrera, A Brzovic, M Gaete, L Burgos, E Arancibia

Fragmentation is one of the most relevant parameters in the design and operation of a mine using the caving mining method. Fragmentation affects all subsequent operations, including extraction, comminution processes, secondary blasting and transportation.There are a number of different models in the literature to estimate the size of the ore fragments that report to the drawpoints; however, there is still no industry consensus about which one to use. This paper proposes a new model for predicting the fragmentation reporting to the drawpoints that is based on the geotechnical unit characteristics, extraction height and column of primary ore. The model is developed from observations of fragmentation measurements in different mine sectors of Codelco’s El Teniente mine in Chile.This work focuses on the following three steps:collecting fragmentation and hang-up data from several mine sectorsdeveloping a geotechnical block model using oriented core placed within the main geotechnical unitsanalysing the data and modelling the fragmentation process.The proposed model is used to discuss the mechanisms and the influence of preconditioning on the size of the ore fragments that report to the drawpoints.CITATION:Brzovic, A, Vallejos, J, Arancibia, E, Burgos, L, Delonca, A, Gaete, M and Barrera, V, 2016. Analysis and modelling of the fragmentation process – case studies at El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 305–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Donald O. Capstick

A mineral survey of the approximately 144,000-acre Borah Peak study area was conducted by the U.S. Bureau of Mines in 1985 at the request of the U.S. Forest Service. The area studied included the Borah Peak RARE II roadless areas (No. 14210, 119,864 acres of land recommended for wilderness designation; and No. X4210, 18,440 acres of land recommended as non-wilderness) and other contiguous Forest Service administered land. The study area is in Challis National Forest in southeast Idaho about 30 miles south-southeast of Challis, ID. Burnt Creek, a conterminous study area to the northeast, on lands administered by the U.S. Bureau of Land Managment, was examined concurrently. Dolomite and limestone inferred reserve bases exceed 1 billion tons each within the Borah Peak study area. The material is widespread and of high quality. Extensive sampling and more detailed mapping are required to better define the resources; however, ample dolomite and limestone occur nearby, outside the study area. Dolomite is the main constituent of several geologic formations within the study area. Sample analyses indicate that the more than 1,000-ft-thick Jefferson Formation dolomite is the most pure and is equivalent to material being mined at a dolomite-to-magnesium processing plant near Addy, WA. Analyses from limestone-bearing formations underlying much of the study area indicate that large quantities of the limestone may be suitable for a variety of uses.

Jan 1, 1987

This report has been prepared in response to a request by the Bureau of Land Management (BLM) Fairbanks Alaska District Office that the Bureau of Mines quantitatively assess the potential supply of minerals from undiscovered deposits in the White Mountains National Recreation Area (WMNRA) and the western part of the North Steese National Conservation Area (SNCA) in Alaska. The assessment will be used to assist in future land-use decision-making. Resource Management Plans (RMPs) for the WMNRA and the SNCA were approved by the BLM in 1986. These plans imposed significant restrictions on new mineral development in the two areas. The level of public concern regarding these actions, especially on the part of the mining industry, has spurred BLM to seek additional information about the potential supply of minerals from the two areas with assistance from the Bureau of Mines. The assessment focuses on an area within the WMNRA and the SNCA which has been administratively closed to mineral entry. The study area encompassed approximately 1.24 million acres and included all of the WMNRA and the western portion of the North SNCA (fig. ES-1). Three quantitative estimates of the potential supply of minerals from the study area were developed: 1) For all lands in the study area, assuming that they are open to mineral entry-the baseline analysis; 2) For those lands which have been closed to mineral entry; and 3) For eleven prospective mineral activity areas, assuming that all are open to mineral entry.

Jan 1, 1989

By R J. Mills, B S. Sinclair, D A. Fergusson, A G. Goldstone

In 2005, Solid Energy New Zealand Limited obtained non-notified consent for the disposal of 1Mt of coal ash at the Rotowaro minesite, forming part of a coal supply agreement with the Huntly Power Station. The consenting of major mine site activities has historically required wide consultation and involves notification of the application.   The risk and cost associated with consultation can be significantly reduced via a non-notified process. A non-notified consenting process necessitates environmental effects to be shown to be æless than minorÆ, which requires the combination of robust science and a pragmatic approach to design, assessment of environmental effects, and consenting issues.   Key issues examined included consideration of how to practically operate a significant disposal project within the confines of an operating mine, minimising the costs, civil and geotechnical design and practical issues associated with traditional disposal. Environmental issues specifically related to the coal ash, led to a site specific performance driven approach to management rather than relying on conventional prescriptive approaches. Environmental issues of concern include the leaching of boron and aluminium from ash into groundwater and mine water management systems where both boron and aluminium can occur at elevated levels.   Coal ash exhibits unusual geochemical characteristics reflecting the primary coal composition and the combustion process. The dominant coal type combusted at the Huntly Power Station is derived from Rotowaro and the resulting ash is cementitious and has a high alkalinity. As a result the disposal design is based on the characteristics of the ash itself rather than the material into, or onto which the ash is disposed. Non-notified status was able to be achieved through consideration of these key characteristics of the ash, ensuring that the dimensions of the disposal site and each location was designed to minimise the flow of groundwater through the ash and demonstrating that the physical ash disposal effects are less than minor compared to the consented mining operation.

Jan 1, 2006

By H. E. Lee, D. Ingvoldstad

AT Bunker Hill the original charge storage and preparation system was installed in 1917 to accommodate lead-silver gravity mill products. Only minor tonnages of wet fines such as vanner and flotation concentrates were received. Charge flux and diluent requirements were provided by an ample supply of siderite middlings and coarse lime-rock. While oversize material was crushed through %-in., the use of roll crushers in series resulted in a more or less granular, free-running charge of adequate porosity. Under such conditions, receipts could be proportioned directly from receiving bins, and suitable blending was obtained by passing the resultant layered composite through a small Stedman disintegrator. This elementary system served well for production and smelting of an extremely lead-rich sinter, in the low column blast furnace. Here sinter physical quality is less critical, and appreciable quantities of raw flux and oxidized ore may be charged directly to the blast furnace without seriously impairing furnace capacity. Prior to 1938 the relative proportions of zinc receipts were low and extraneous flux requirements at a minimum. However, subsequent war-inflated zinc demands brought marked increase in fine concentrate and slimy zinc leach residue receipts and an abrupt introduction to smelting a more refractory zinciferous charge. The higher temperature demands of the more refractory zinciferous charge required a higher smelting column and the higher column, in turn, rendered the blast furnace less receptive to improperly prepared feed. Inadequate presinter processing facilities prevented the production of acceptable sinter, and blast furnace production declined to 50 pct of former capacity. In view of a prevailing contention among lead metallurgists as to the deleterious action of high zinc slag on blast furnace capacity, it was natural to overstress this factor and to concentrate on possible changes in furnace design. Another interpretation was that primary correction should be sought through expanded sintering facilities. This divergence of opinion, together with the extreme material shortages of the 1940's, delayed corrective

Jan 1, 1957

THE object that the writer has mainly in view in presenting this paper is to draw the attention of those connected with the technical side of the industry to the unsatisfactory and by no means up-to-date methods employed in estimating the tin contents of an ore. At the same time, what is regarded, from the writer's personal experience, as a satisfactory and reliable method is explained in detail. It is a curious fact that for the last 25 years tin·assay methods have made little or no advance, while those now in general use ill connection with copper and lead ores can scarcely be compared with those then obtaining, so greatly have they been improved upon. Though it. is not altogether expected that the method herein advocated will at once meet with general approval, the writer hopes the resultant discussion may bring out points that have hitherto escaped detection.FIRE METHODSThe old Cornish method of smelting with anthracite is now obsolete. The cyanide assay, although unreliable, is still much used because of its simplicity. In the Malaya many buyers of tin ores use the cyanide assay, the smelting being carried out generally in a benzine furnace. It is essential that the smelting with cyanide be performed at a low temperature. Even then, impurities, such as Sb2S3 and...

Jan 1, 1912

By James D. Eklund

Towards the goal of improving safety, economy and efficiency of scaling in underground metal/nonmetal mines, Battelle developed a combination prying/hammering scaling tool. A prototype was subjected to limited testing 1) to verify its operational functions and 2) to assess its potential capability in future underground testing.

Jan 1, 1983

By using knowledge-based technology to create a Virtual Mining Enterprise and integrating it with existing technical and financial computer systems, a gold mining company has been able to reduce the time taken to produce a mine plan from 14 weeks to less than one week. Typically, the mine planning process requires circulating and managing large amounts of information. Even with the use of computers in todayÆs business, this is often still a manual process involving file transfers and individualised spreadsheets. Mine planning also involves understanding and managing large quantities of complex and interrelated variables. Added to this is the ever changing dynamics and constraints associated with the business of mining. These issues not only hamper the planning process but also question the validity and usefulness of the mine plans being generated. By integrating the information and knowledge of the numerous departments involved in mine planning into one core Knowledge Base - so called æone version of the truthÆ, - mining companies are able to overcome these pitfalls experienced in traditional planning methods. Once set up, the Knowledge Base creates and runs a virtual mining enterprise with which to visualise and test various scenarios of mining, business and logistical activities. The final output is an optimised enterprise-wide plan with clear and detailed instructions for each of the divisions of the company.

Jan 1, 2000

By Z. Duan

A novel concept involving the deployment of chemical stabilization has the potential to eliminate the need of slurry impoundments and significantly reduce the release of trace elements from the high surface area fine coal waste. The process involves mixing the fine waste generated from the underflow of a thickener operation with chemical stabilization agents to tie up the water and to create a solid waste material that can be discharged directly. Portland cement, sodium silicate, F type flyash, C type flyash and hydraulic lime were evaluated as stabilizing agents. A detailed experimental study has been conducted to identify the conditions that provide the maximum compressive strength within a short curing time. Results to date show the ability to achieve compressive strengths adequate for equipment to maneuver on using a Portland cement concentration of around 10% by weight. Quick-setting concrete was not found to enhance stabilization time and compressive strength.

Jan 1, 2012

By S. J. Frank

Ferroalloy furnaces are well known to be extremely difficult to control from a metallurgical perspective. Mostly metallurgical control is still reactive in nature, causing a significant amount of reworking and product blending to achieve a proper product specification. Despite numerous efforts towards the model based control of primary smelting operations, actual metallurgical feed forward control seems to remain elusive. One of the key reasons in the failure to model these metallurgical reactors well, is that fundamentally orientated pyrometallurgists, statisticians, data miners and control engineers very often have diverging ideas how to model these systems. Furthermore, metallurgists have often come to rely on their ability to develop empirical regression models of furnace behaviour, as they have lost their faith in the ability of thermochemical and metallurgical engineering fundamentals to accurately predict the outcomes from furnaces. This paper shows how good thermochemical modelling can be combined with proper technological and systems analysis, as well as a proper inventory model, to predict the alloy and slag chemistry with good accuracy one tap into the future, at a time horizon of typically around 4 to 6 hours. For this modelling approach, a number of tools will be used, such as data reconciliation, thermodynamic modelling using Fact Sage®, inventory and heel estimation, neural networks and statistical data exploration. Furthermore, systems identification theory will be combined with the approaches given above to develop a truly dynamic predictive model. This paper seeks to demonstrate the need for a hybrid approach, which incorporates plant data and readily accessible thermodynamic data to develop a proper dynamic model.

Jan 1, 2004

By Patrick R. Taylor

In the search for the development of more "environmentally friendly" and more intensive waste disposal approaches to meet more and more stringent environmental regulations, thermal plasma-based processes are considered one of the most promising alternatives to well- established technologies such as incineration. This paper presents an overview on the research and development status of thermal plasma-based waste remediation technologies. The properties of thermal plasma are described. Due to its unique feature of high-energy intensity and super high temperature, thermal plasma is particularly capable of destroying organic- containing wastes. Its potential and promising application to waste remediation may include: treatment of incinerator ashes; metallurgical dusts (especially, electric arc furnace dust); medical wastes; radioactive wastes; and other Resource Conservation and Recovery Act (RCRA) listed hazardous wastes. Many research institutes and vendors have been involved in the development of thermal plasma-based waste treatment technology encouraged by the cleanup programs supported by the Environmental Protection Agency (EPA), the Department of Energy (DoE) and the Department of Defense (DoD). More recently, thermal plasma-based waste treatment technologies (sometimes called plasma-enhanced pyrolysis) are focused more and more on not only just destroying organic wastes but also on how to practically, and economically recover energy contained in the organic waste materials in addition to the recovery of metals in order to offset the high operating costs.

Jan 1, 2003

By D. S. Saxena, Jack K. Tuttle

Lack of understanding of useful applications of explosives on construction work stem primarily from the fact that explosion is commonly associated with destruction. On rock excavation and other construction works a certain quantity of explosive is harnessed to perform useful work at the source e.g. blasts to disintegrate rock. Development in rock blasting techniques, including the use of multiple-row blasting with short delay ignition, have made it impossible to excavate rocks close to or below buildings even in closely built-up areas. To permit the use of explosives on construction projects, in ways that will not damage existing structures, guidelines have been developed from careful measurements of intensity of ground vibrations. Accurate electronic instruments are now available for doing this. PLANNING AND CONTROL Blasting operations must be carefully planned and carried out to avoid discomfort to persons or damage to property. This increase in the use of rock blasting in city areas alone has led to a number of problems due to ground vibrations, air shock waves, and the psychological effect of noise. While the latter seldom if ever causes damage, it does create irritation and discomfort to persons living or working near the blasting sites. A result of this is a steady increase in the number of complaints in respect of damage to houses and other premises. Many such complaints are genuine and damage may undoubtedly be caused when incorrect blasting techniques are used.

Jan 1, 1997

By C. Musingwini

The Bushveld Complex is economically significant and strategically important to South Africa, thus it is imperative that optimal extraction of platinum group metal (PGM) resources on the Bushveld Complex is achieved. Optimal extraction broadly requires that the maximum amount of ore is extracted by excavating and hauling the minimum amount of waste in the shortest possible time, at the least cost, and in the safest and most environmentally acceptable manner. In open-pit mine planning this entails among other things, minimizing the waste stripping ratio, whereas in underground mine planning it includes minimizing the metres of waste development. In conventional mining, the main development that is in waste or partly in waste and defines the mining grid pattern includes levels and raises. It was prudent to consider optimizing level and raise spacing in conventional mining because the method is a prevalent mining method on the Bushveld Complex accounting for nearly 70% of platinum production.

Jan 1, 2010