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By L. A. Weakly

The requirement for large diesel equipment to be certified for operation in potential gassy mine conditions in western oil shale mines motivated a design engineering project to develop a dry exhaust conditioner system to replace traditional wet scrubber technology. A dry exhaust conditioner for a 600 hp diesel engine was designed and fabricated for retrofitting into a 600 hp underground haul truck. The engine conditioner package was taken through a simulated certification process at the Mine Safety and Health Administration (MSHA) Approval and Certification Center to refine test procedures and to uncover any flaws in the dry exhaust conditioner technology. The engine/exhaust system was then installed in an underground haul truck to demonstrate mine-worthiness of the system. No inherent features were discovered that would prevent the system from meeting test requirements. However, the tests did point out several deficiencies in the prototype design.

Jan 1, 1989

By John L. Stafford

The ROEMMC combustion system was originally conceived as a means of utilizing solid fuels that would otherwise have been wastes requiring disposal and convert these fuels into useful energy sources. This concept follows as an extension of the application of residual waste incineration with energy recovery practiced in the lumber, manufactured board, sugar cane, and other industries. The incineration of these wastes in the furnaces of steam generating equipment is thoroughly described (1, 2, 3, 4, 5, 6, 7). The fundamental principle of the ROEMMC system is temperature control which makes possible the maintenance of the non-combustible fraction of these solid fuels in a dry solid state and their separation from the gaseous products of combustion. This philosophy of ash removal and the "slagging" philosophy are compared. The ROEMMC equipment function and applications are described.

Jan 1, 1978

By A. W. Laughlin

Laser-Induced Breakdown Spectroscopy or LIBS can be used to provide exploration companies with precise and accurate chemical analyses in the field, in real-time, resulting in major time and cost savings. Using a Field-Portable Analyzer (FPA), anomalies can be followed up immediately while crews are still in the field. Lower limits of detection (LLDs) are element dependent, but many are sufficiently low to be useful in exploration. LLDs in ppm for selected elements of interest are: Be-2, Cu-3, Zn-20, As-200, Sb-500, Pb-30, Ag4, Mo-100, B-33, Ti-500, V-350, and Cr-1. LIBS analyses require little or no sample preparation.

Jan 1, 1999

By P. Somasundaran, J. T. Kunjappu

Spectroscopic techniques are becoming increasingly popular for characterizing the interior of adsorbed layers of surfactants and polymers at solid- liquid interface as well as in the identification of com- pounds on mineral surfaces. This review encompasses the application of fluorescence and ESR spectroscopic techniques to reveal the microscopic environment of the adsorbed layers of surfactants and polymers on minerals with a special reference to the adsorption of anionic surfactants (e.g., sodium dodecyl sulfate) and polyelectrolytes (e.g., polyacrylic acid) at positively charged mineral (e.g., alumina) - water interfaces. Finally, the utility of XPS and auger techniques to identify the surface elemental composition of different mineral species has been related to their flotation efficiency.

Jan 1, 1987

By Michael Robert Hodson

The views expressed in this paper are those of the author and do no necessarily reflect those of CRU. The Extent of Government Involvement In 1982 national governments in the Non-Socialist world owned at least some equity share in an estimated 49 percent of the bauxite mining capacity located in their own countries.* By comparison, as Figure 1 shows, in the same year governments owned at least part of an estimated 33 per cent of primary aluminium smelting capacity. In other industries, national, or state governments in 1982 held at least part ownership of mining capacity in 42 per cent in the copper industry, 34 per cent in the tin industry, 23 per cent of the zinc industry, 15 per cent of the lead industry and 11 per cent in the nickel industry. Thus while within the aluminium industry attention has focussed on the share of government ownership in the primary aluminium sector, national government involvement through ownership is larger in the bauxite sector. Moreover, ownership by government is more widespread in the mining of bauxite than in the mining of all other principal non-ferrous base metals. Yet while the equity participation of governments in the bauxite sector is widespread, it is but one of many forms of government involvement. In addition to direct ownership or equity participation domestic government involvement has taken the form of legislation to protect the environment, controls on the level of production, insistence on the export of ore, pressure to maintain levels of employment, controls on the type of fuel used, foreign exchange *Capacity which is owned in whole or in part is included within the state sector, but capacity in one country which is owned by a wholly or partly owned government company in another company is not included in the state sector; e.g. the capacity of the Trombetas mine is included in the state sector but the capacity of Delphi bauxite would not be included.

Jan 1, 1984

By S. K. Kawatra, T. C. Eisele

Coal-cleaning operations commonly produce a fine-waste stream containing a considerable amount of coal. The recovery of this coal is normally not economical because the coal is mixed with large amounts of difficult-to remove clay slimes and is often heavily oxidized or contaminated. Conventional froth-flotation machines cannot, in a single flotation stage, produce an acceptable product from such material, and even flotation columns often have difficulty cleaning this type of feed. A new type of flotation column was designed specifically to deal with these problems, and a column of this design was installed and tested in a coal-cleaning plant in Ohio. The feed coal tested was the plant&apos;s tailings-thickener product. The coal was 80% -176 µm and had a heating value of 8401 Btu/ lb. The coal contained 39.8% ash, as fine clay, and 2.83% total sulfur. Because previous attempts at conventional flotation of this type of material had been abandoned, plant personnel believed that the coal was too heavily oxidized and contaminated for flotation to be effective. However, by using the new column it was possible to recover up to 85% of the calorific value in a product containing < 11 % ash, and it was possible to recover 60% of the calorific value in a product containing <8% ash. In addition, the bulk of the pyritic sulfur was also rejected from the coat.

Jan 1, 1996

By J. Fox, C. Allen, A. Greth, K. Kocsis

"It is the duty of the mine operator to ensure the mine environment is healthy and safe for the mine workers. For deep and hot underground mines, this requires maintaining adequate working temperatures by means of mitigating the heat load generated by strata, auto-compression, mining equipment, explosives, ground water, and human metabolism. The heat load is best reduced by minimizing the amount of heat transferred to the mine air from these sources and through the use of efficient ventilation with effective cooling systems. The heat emitted by mining equipment and vehicles contribute a significant proportion to the combined heat load of an underground mine. This is especially a problem for diesel equipment due to the fact that besides heat, a large amount of water vapor is produced, which increases the humidity in the production workings. Diesel engines have proven advantageous in recent history due to their high power output and reliability. However, as mines continue to become more mechanized and deeper the climatic problems introduced by elevated heat generation will continue to rise. With that, the issue of heat generated by diesel equipment must be addressed. The economic alternative for diesel engine equipment fleets in underground mines is the electric engine. Technological advances in battery technology, increased mechanical output and improved reliability have made the electric engine significantly more competitive in comparison to diesel engines. Because electric engines do not utilize internal combustion, the heat produced by them is significantly less than of the diesel engines. Battery powered mining equipment likewise eliminate diesel particulate matter (DPM) produced by diesel engines. Utilizing battery electric equipment in underground mines provides many advantages, such as: (a) reduced heat load, (b) healthier and safer environment for the mine workers, and (c) reduced mine operating costs due to lower ventilation requirements. This paper will highlight the health and cost benefits of using battery/electric fleets versus diesel fleets in deep and hot underground mines. The study analyzes simulations produced from thermodynamic ventilation models. Early simulations show significant cost reductions in terms of net present value (NPV) when comparing the air volume requirements for battery/electric equipment versus diesel powered equipment for the same production rate. INTRODUCTION The competitiveness of the world mineral market demands that mine operators continue to increase production and decrease costs as commodity prices fluctuate in often unplanned directions. This has forced underground mines to operate at deeper depths and to become more mechanized to remain competitive. Because of these changes, ventilation challenges have continued to increase as the mines combat an enlarged influx of contaminants such as heat and diesel particulate matter (DPM)."

Jan 1, 2018

By Richard J. Robbins

This paper is presented with particular reference to the findings of the OECD Advisory Conference on tunneling held last July in Washington D. C. A great deal has been said about the Conference in the past few months, but it may be appropriate to review briefly the background and objectives of the Conference to better understand how the mining community can relate its underground excavation problems to the results of the Conference. OBJECTIVES OF THE OECD CONFERENCE The world demand for tunneling (the term tunneling is used here loosely to include almost all forms of underground excavation) is expected to grow at an in- creasing rate. During the decade of the ?70&apos;s, the demand is expected to at least double by comparison with the previous decade. Much of this increase in demand will be due to the rapid growth of urbanization around the world. As urban populations grow larger and denser, the conservation of surface land and the quality of the environment become more important. This aspect of the increasing demand poses a difficult challenge to those who must plan and implement urban development.

Jan 1, 1970

By Yuting Xue, Lihong Zhou, DAVOOD BAHRAMI

The paper discusses the use of machine learning (ML) to develop a predictive model for determining the location and size of underground mine fires using simulated ventilation data. The study highlights the importance of prompt fire location determination for effective firefighting strategies and reducing injury risks. The ML model was trained with simulated data and achieved an accuracy score of 0.920, which improved to 0.962 by grouping closely connected airways.

Sep 1, 2023

By R. S. Shoemaker

Expanded markets for copper in the past few years and a consequent search for new ore bodies have revitalized the widely known but seldom applied method of producing copper called heap leaching. This term should be differentiated from dump leaching in that the latter is applied to dumps of mixed oxide and sulfide ores (although either may predominate) that have been too low grade to beneficiate and have, therefore, been stripped off the higher grade underlying sulfide ores. Heap leaching is defined here as the process applied to oxide ores which have been mined solely for the purpose of leaching. In this case, all costs of mining the ore become a part (and a substantial one, as will be shown) of the cost of the copper produced, whereas in dump leaching the mining cost has already been accounted for as a stripping cost for the sulfide ore. Of course, with newly opened ore bodies, stripping costs may be divided through accounting procedures, between the copper produced by the mill and that obtained by leaching, but in general this type of operation must be economic on the basis of the sulfide ore alone. Heap leaching, as a beneficiation method, is unique in that it is the only process used for the recovery of a metal in which the time involved from mining the ore to metal production is measured in months instead of hours or at the most, days, Then too, after the ore body has been depleted and mining has ceased, metal production will continue for some substantial period of time. Heap leaching is also unique because unlike any other method of beneficiation, metal recovery cannot be accurately forecast ahead of time and recovery will never approach that of a conventionally milled sulfide ore or even that of a vat leached oxide ore. Counter-balancing this drawback, however, is the relatively low capital expenditure necessary to put a heap leaching operation into production and the consequence that smaller ore bodies which would not support the higher capital cost involved in a vat leaching plant can be made into producers. Stated more simply, in heap leaching the operator accepts low recovery in exchange for low capital costs and the break even point, that is, where the operator should go to vat leaching with its higher recovery and higher capital costs, is a matter of economics and also, to a great extent, a matter for the nature of the ore to decide. For instance, an ore that will vat leach in 7 to 10 days using 7 pounds of sulfuric acid per pound of copper produced might use double or triple that amount of acid during the months that are required for heap leaching.

Jan 1, 1968

By F. L. Pirkle

A heavy mineral deposit about 1.6 km (1 mile) in length, 0.13 km (0.08 mile) in width and averaging about 3 m (10 ft) in thickness is exposed approximately 130 km (80 miles) east of Denver, along Interstate 70, in Elbert county, CO near the town of Limon. The deposit is exposed in a geomorphic feature known locally as Titanium ridge. The dominant heavy minerals, accounting for about 70% of the total heavy-mineral suite by weight, are ilmenite, garnet and zircon. The mineralized zone appears in a series of visually interpretable facies that are stacked vertically and represent subtidal, forebeach, backbeach, washover fan and aeolian depositional environments. These paleoenvironments are analogous to depositional environments represented by a modern heavy-mineral bearing facies tract on St. Catherines Island, Ga. Thus, Titanium ridge provides evidence that heavy-mineral accumulation models for late cenozoic deposits in the Georgia and Florida coastal plains are applicable to heavy-mineral deposits of the Western Interior subsurface and, by implication, the Western Interior Seaway, extending from Mexico to the Canadian Arctic.

Jan 1, 2012

By D. A. Poukhovski

Two integral components of the 30 CFR 48 training requirements mandated for new miners, newly employed experienced miners, and the annual refresher training of all miners are hazard recognition and prevention of accidents. In these categories, instruction shall include the recognition and avoidance of hazards present in the mine, and a review of accidents and their causes. Unlike instruction preparation for fact-based material, program development for hazard recognition places a particular challenge before safety-training specialists because they are often limited in their ability to adequately gauge the trainees&apos; levels awareness prior to training. Further, they must also assure that the training is relevant, and it is presented in a thought-provoking manner. Computer-based instruction is particularly well suited for assisting trainers in developing hazard-recognition topics because it can be used in pre-training and post-training modes for assessment of training effectiveness, in addition to use as a presentation tool. Therefore, this paper will present a recent approach developed at Penn State to apply this technology for assessment and instruction of accident prevention through hazard recognition, with an application prepared for surface coal mines.

Jan 1, 1997

By C. N. Bensley, S. K. Nicol, R. Lamb, G. W. Kidd

Flotation circuits in the metalliferous industry recover high value concentrates from very fine (minus 0.lmm), low grade, slow-floating feeds. Flotation columns acting as final cleaners within these circuits offer the benefits of higher grade concentrates, reduced circuit complexity, improved control and reduced power consumption. By contrast, in the coal industry, these benefits have not been realised, principally because columns are not well suited to the treatment of conventional coal flotation feeds (minus 0.5m). However, this does not imply that columns do not have a place within the coal industry, rather that they must be applied in a role where all the unique advantages of column flotation can be of benefit. The development of a commercial scale column to recover discarded ultrafines from the Riverside preparation plant of BHP-Utah Coal Limited is discussed. Particular emphasis is placed on the column design features pertinent to the recovery of ultrafine coal. Pilot and commercial scale column performances are compared. The results of the commercial scale testwork indicate that a full installation at the 5.5 MTPA Riverside plant would annually recover additional coal worth $US 6.6M.

Jan 1, 1988

By William Gleason

With its 2011 acquisition of rival equipment company Bucyrus International, Caterpillar added underground mining and large shovels to its line of products and further solidified its standing as the leading mining equipment manufacturer in the world with solutions for every aspect of mining. When Caterpillar spent $8.8 billion to acquire Bucyrus, the global mining business was flourishing, as mining companies around the world worked to keep up with demands for nearly every commodity. Flash forward to 2013, and the global mining landscape looks very different. Lower demand for raw material from China and India and falling commodity prices have forced most mining companies to pull back on their production. The reductions from the mining industry have hit equipment makers like Caterpillar and Komatsu hard. In October, Caterpillar reported that its quarterly earnings had fallen 44 percent. The changing conditions have also changed the narrative from Caterpillar and other equipment makers to customers from offering solutions to move the most tons per hour, to now offering solutions for the lowest cost per ton. In September, Caterpillar hosted some of its mining customers and the trade press at its Tinaja Hills Demonstration and Learning Center near Tucson, AZ to talk about its range of products, from its MineStar System designed to help increase efficiency through better equipment management and planning, all the way up to the massive Cat 7495 and 7495HF electric rope shovel lines acquired through the Bucyrus takeover

Dec 1, 2013

By J. Rothschild

I would like to thank the Society of Mining Engineers for inviting me as well as the other distinguished panelists to spend a morning reviewing and discussing the handling and shipping of industrial minerals. I also would like to thank my management, Cometals. Inc. for permitting me to take time out from the daily hectic pace of marketing and trading to share with you some of our experiences and expertise. Cometals, Inc. is a wholly-owned subsidiary of Commercial Metals of Dallas. The transportation and handling costs of industrial minerals frequently are a major component of the value of the goods marketed and, therefore, it is only natural that close attention should be paid to them. Many of the industrial minerals require special handling to assure that the material reaches the consumer without being contaminated or getting wet. I invite you to accompany me through the various steps involved in "delivering the goods" to the consumer.

Jan 1, 1989

By R. G. Lundquist

The idea that fragmentation for mineral processing results from some tradeoff between increased drilling and blasting and increased load on the primary crusher is well known. In a previous paper (Lundquist and Konya, 1963) the authors reported on the results of a laboratory scale study which attempted to quantify this tradeoff in energy terms. If we look only at the production of new surface area, blasting is 1700 times as energy efficient as crushing. On an energy cost basis, crushing is 57 times as expensive per unit surface produced as blasting with dynamite and more than 700 times as expensive as blasting with ANFO. The comminution process at an open pit operation starts with the drilling of blast holes and ends after the material has gone through the fine grind circuit. Operators usually break the process into several separate operations and do their cost analysis based on this approach. Often drilling and blasting is considered as one system and crushing and grinding are considered as one or two separate and independent systems. Operators will independently optimize each system. The cost for the drilling and blasting system is obvious in operations which use contract drillers to do the drilling and either contract the blasting to a distributor or do the blasting themselves. The cost of rock breaking in this manner is readily available since the contract driller will supply a monthly drilling cost to the operation and either the distributor who is contracting the blasting or the distributor who is supplying the powder to the blasting operation will also supply a monthly billing. In either case, the costs can easily be seen on a monthly or per ton basis. They are not difficult to compute even when drilling and blasting are done entirely in-house.

Jan 1, 1985

By Thomas Pea, Heiner Kontrus, Jérôme Steinkühler

In tunnel condition assessment, the trend is towards comprehensive 3D measurement combined with high quality image texture to document and quantify damages to the tunnel surface and to create a cohesive data base of the structural conditions throughout its lifespan. The faster such measurements can be made on site, the less it impacts traffic conditions of the highly sophisticated subway systems. The Dibit high-speed 3D scanning system which is based on Photogrammetry and LiDAR technology enables data acquisition in tunnels at a speed of up to 60 mph. Given the high rate of speed the system can operate, tunnel shutdowns can be drastically reduced, and tunnel safety increased. The photorealistic texturing of the 3D-model allows the identification and analysis of smallest material damage (e.g., cracks ≥0.3 mm wide). The publication illustrates technical details and 3D results of the innovative system from measurements that were performed in the subway tunnels of the Bay Area Rapid Transit System in San Francisco, CA (total length 66.23 km).

Jun 13, 2021

By David A. Summers

Historically, the presence of methane has been a problem, mainly in and around the working areas of active coal mines, and only in these area has drainage been considered. Drainage, where practical, has been achieved through the drilling of holes forward into the coal and the surrounding strata from the working area. These holes generally have been short in length, although where methane drain- age operations around a longwall face have been undertaken, the holes have had to be longer in order to adequately drain from the center of the face into the access gate roads. In recent years, attempts have been made to degasify the coal seams in advance of mining, without disruption of the mining cycle. This is done by drilling much longer horizontal holes through the coal in advance of the working area. Under the aegis of the Federal Government, methods have also been developed for draining seams of coal of their methane content in advance of mining, but from shafts sunk from the surface, without using the active area of the mine as the location for the drill holes.

Jan 1, 1979

By S. Michael Feroz, Paul Gribbon, Jan Rosholt

Approximately six billion gallons of combined sewage are discharged annually into Willamette River and Columbia Slough through Portland’s combined sewer system. The Columbia Slough Consolidation Conduit (CSCC) is an important element of mandated Combined Sewer Overflow (CSO) abatement. It includes2,548m (8,361 ft.) of 3.7 m. (12 ft.) internal diameter tunnel. The CSCC alignment traverses the UP railroad, Columbia Boulevard and parallels an old sewer. Geologic conditions include river alluvium and fine to coarse-grained flood deposits containing cobbles and boulders. This paper describes design and construction of a tunnel in soft-ground, with shallow cover and close to an old concrete sewer.

Jan 1, 1999

By L. C. de Kooker, K. Esmaeili, I. Musonda, M. Ferentinou

This paper presents the results of an investigation into the effect of pore pressure regime on the factor of safety (FS) and the anticipated critical failure mechanism for a fly ash storage facility. In this study, pore pressure measurements from standpipe piezometers and pore pressure estimated from seepage analysis were used for a comparison of the estimated FS for a fly ash slope. This comparison was applied for static and seismic scenarios. To account for the uncertainties resulting from the limited data available and support a qualitative risk assessment evaluation, a probabilistic analysis was performed. The slope stability analysis was conducted in 2D and 3D, adopting the limit equilibrium analysis approach, and a finite element seepage analysis. The results suggest consistency of failure surfaces for 2D and 3D and an increase in FS values of 5 percent for the 3D approach, limitations of standpipe piezometers. The study demonstrated the sensitivity of the FS value, and the implication of adopting representative material properties, and water table levels, especially in cases where limited data are available, and assumptions need to be made to assess the long-term stability of a fly ash dam facility.

Aug 1, 2024