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By Robert E. Barry

For new coal-fired power plants, federal regulations require that emissions of sulfur dioxide be limited to 1.2 pounds for every million BTU'S burned. This is equivalent to coal with a sulfur content of roughly 0.7 percent for Eastern bituminous coals and roughly 0.6 percent for Western sub-bituminous coals. The states and their political subdivisions are free to apply more stringent standards and to develop implementation plans covering existing and new units. Most Western-sub-bituminous coals contain less than 1% sulfur and hence their use, in many cases, will allow a utility to meet the regulations. However, there are problems in using such coals in furnaces designed for Eastern bituminous coals, and furthermore it will take many years to open mines and provide transportation facilities to utilities which are now burning coals with a higher sulfur content. Moreover, pending federal legislation would outlaw strip mining on land to which the federal government owns the mining rights. Those utilities who, for one reason or another, intend to continue burning Eastern bituminous coals with sulfur contents in excess of 1 percent are faced with removing SO2 from the stack gases. The alternative of utilizing coal gasification where the sulfur is removed prior to burning in a power plant is still in the early stages of development. Therefore, a large number of processes are under development for SO2 control.

Jan 1, 1974

By Stephen J. Swan

Feed-forward control (i.e. the forward flow of information in a control system ) is a simple and flexible approach to over-all control of a ball mill-rake classifier grinding circuit. The system described here uses mill power, feed rate, mill dilution water flow rate, and classifier dilution water flow rate only, to control mill load, throughput, mill solids, and classifier solids as well as classifier overflow grind. The mill load is controlled by a simple feed-back control loop, while mill solids and overflow grind are controlled within close limits by a unique non-linear feed-forward water control system. In effect the control follows a limited mathematical model of the grinding circuit. The configuration minimizes deviations in overflow grind due to changing ore conditions, but since it is open-loop, and the model is not complete, it is affected by changes in total ball charge and liner wear. These effects are fortunately gradual, and changes in the grind can usually be kept to within ± 1% of a target continuously for several days without adjustment. Control adjustments are made with feed-back from laboratory composites. This control system has won enthusiastic operator acceptance; it is easily started up and shut down; grind-outs have been eliminated along with flotation machine flooding and mill spills. Standard measurements and components are used throughout providing a trouble-free system design at a moderate cost.

Jan 1, 1970

By I Canbulat, A Mcquillan

This paper presents a parametric analysis showing the impact of virgin in situ stresses on a shallow (less than 100 to 150 m) high slope in a jointed sedimentary rock environment. Slope stability is assessed at varying ratios of slope orientation and horizontal stresses. The results of this study indicate stress conditions should be included in stability assessments of excavated slopes, particularly where structure is orientated perpendicular to the direction of horizontal stress. Some consideration of stress state is applied in deep open cut pits (eg those with planned excavations of 400–1200 m) (Myrvang et al, 1993; Stacey et al, 2003; de Bruyn et al, 2014; Kozyrev et al, 2015). Dodd and Anderson (1972), Kalkani and Piteau (1976), Lee (1978), Coulthard et al (1992), Noorani et al (2011) have studied the effect or horizontal stress and its impact on slope stability, showing that tensile stresses tend to develop at the crest of the slope, with larger tensile zones for higher horizonal stresses and steeper slope angles (Stacey, 1970, 1973; Sjoberg, 2013). However, the consideration of virgin stresses on shallow slope stability is less frequent (Lynch et al, 2005; Dight, 2006; Lucas, 2006; Sjoberg, 2013). This has led many geotechnical engineers to believe the impact of virgin in situ stresses on open cut slope stability is minimal and not worth time or consideration in modelling, or their effects on slope stability are still poorly understood (Stacey et al, 2003; Sjoberg, 2013).

Nov 29, 2022

By A. Lashagri

This paper presents research results on assessment of environmental impact of digging and loading equipment in surface coal mining. Environmental impact is accessed through the equipment exhaust and dust emissions, and sound level. Exhaust emission is related to carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOx), and volatile organic compounds (VOCs). Dust generation is expressed through the particulate matter PM10 and total suspended particulate matter (TSP), while sound is presented through the sound pressure level. Modeling of environmental impact of digging and loading equipment is conducted in Microsoft Visual Studio.NET software package. This research is a part of a boarder project on development of software system for the selection of productive, cost-efficient and eco-friendly mining systems, which is sponsored by the Appalachian Research Initiatives for Environmental Sciences (ARIES). The research work presented here may be used by mining professionals to aid in quantifying environmental impact of digging and loading equipment and determinate strategies for reducing its overall impact.

Feb 27, 2013

By P Aspinall

Safe work Australia (SWA) has a number of proposed amendments to existing Workplace Exposure Standard (WES) values that may dramatically change how mining workplaces using personal gas monitoring instruments will operate. In consultation with leading gas monitor manufacturers and distributors, an assessment of common Australian alarm settings values and analysis of potential frequency of increased alarm likelihoods has been conducted. This assessment explores the relationships between current monitoring practices, using instruments as health and not just safety tools and identify what will be needed to minimise worker ‘alarm fatigue’ and for common tasks to continue safely. This paper provides the necessary information to aid industry and hygienists to be ‘future ready’ given the likely impact that order of magnitude reductions in time weighted average (TWA) values for NO2, SO2, H2S and other common gases will have on current working practices. Reductions to gas alarm values will provide significant challenges to existing work methods and will require, practical application of the pending future values. Improvements and awareness of instrument capabilities by safety and hygiene professionals will better utilise gas monitors real-time data monitoring capacity and no longer be just ‘safe or not-safe’ instruments. The presentation seeks to promote the practical steps required in setting alarms based on risk consequence and likelihood, increase general awareness of the tools and data available in modern instruments and will enable industry professionals to better manage the challenges of any potential future changes.

Apr 16, 2024

Bowen, R., and Gunatilaka, A. Copper, its Geology and economics. London, Applied Science Publishers, 1977. Miller, D. S. Internal flow systems. (Volume 4 in the BHRA Fluid Engineering Series). 1978. 288 pp. £21,50. MACH 80 The Machine Tool Trades Association of Great Britain (M.T.T.A.) announce that MACH 80 - The International Machine Tool Exhibition - will take place from Tuesday, 22nd April, to Friday, 2nd May, 1980, at the National Exhibition Centre, Birmingham.

Jan 1, 1979

By R. W. O. Kersten

The South African Institute of Mining and Metallurgy recently held a School on iMine Project Planning, the objective being to educate mine personnel who are involved in the planning and management of major projects, as well as young engineers who may become involved in this field. Book prizes for universities Prizes are awarded annually by The South African Institute of Mining and Metallurgy for outstanding academic achievement by mining and metallurgical students at South African universities.

Jan 1, 1985

By Majorkiewicz A

Engineering of gold treatment facilities complete with infrastruc- ture in a remote location such as Papua NewòGuinea present unique problems to the design team. Site location, topography, ground conditions and infrastructure are some of the major hurdles to overcome when setting out on the design of such plants. This paper discusses two such plants, located in two distinctly different areas of Papua New Guinea and the solutions evolved in order to design successful operating facilities.

Jan 1, 1991

By P. Greenfield

The German steelmaking industry has come up with a novel solution to the problem of waste plastics-grind them into particles and use them in the steelmaking process. Plastics make ideal agents for removing oxygen from iron ore in blast furnaces, and save on oil and coal as well. The aim of replacing heavy oil and coal with plastics in blast furnaces is to use them as reducing agents as well as an additional energy source.

Jan 1, 1996

Commonwealth of Virginia, Department of Labor and Industry, Rooms 313-318, State Office bldg , Richmond, Va John Hopkins Hall, Jr., Commissioner of Labor The Department of Labor and Industry publishes an Annual Report containing a review and statistics of industry in Virginia. One section is devoted to the statistics and a review of mining and quarrying during the year The latest or 34th Report (1930) will be sent to those with a particular interest in these matters

Jan 1, 1933

By U. S. Kusel

Extractive metallurgy in Iron Age South Africa U. S. KUSEL, B.A. Hons. (Pta) (Visitor) The finds relating to the metal-working of Iron Age Bantu tribes are reviewed, the following metals or alloys being considered: gold, tin, copper, bronze, brass, and iron. Most is known about copper- and iron-working, but even this is very little, and no one has successfully been able to demonstrate how iron was smelted in the primitive furnaces that have been found.

Jan 1, 1974

By A. Morley

It is difficult to evaluate exploration properties in a manner that is transparent, repeatable and easily re-calculated to cater for different geological interpretations, but the risk-based assessment methodology, the Geological Risk Method, developed and described by Lord et al (2001) attempts to satisfy all these criteria. This paper examines a case study example based on valuations of exploration projects conducted by SRK Consulting using this methodology, and describes some of the advantages and limitations of the method.

Jan 1, 2007

By A Lu, C Wang

The natural semiconducting mineral rutile and sphalerite exhibited highly photocatalytic activities on degradation of methyl orange under visible light irradiation. The isomorphous substitutions of host metal ions by foreign ions and other defect states in natural semiconductors altered the band structure, decreased the intrinsic band gap, and then made them very attractive for solar energy utilisation. Our study indicated that natural semiconductor minerals might be suggested as a new class of cost-effective and solar light-responsive photocatalyst.

Jan 1, 2008

By J. W. Parkinson

A coal-cleaning plant's environment can be hazardous to a computer system. The computer must be more reliable than the coal-cleaning plant mechanical processes if it is to help improve clean-coal quality and yield by performing data gathering and process control tasks. This paper discusses coal-cleaning plant environmental hazards and installation philosophies that can protect the computer. Specific reference is made to a computer system installed at the Electric Power Research Institute's Coal-Cleaning Test Facility.

Jan 1, 1983

By Dan A. Permenter

This paper assesses some of the critical factors that must be considered and addressed in the implementation of small computer systems for technical applications within a coal company. Aspects of hardware selection that are somewhat specific to the coal industry are discussed, and a table of potential areas of application is presented. The dilemma of internal software development is presented and a software development program based on a users group approach is outlined and discussed in detail.

Jan 1, 1983

By Earle J. Klohn

Tailings disposal has rapidly become an area of increasing importance to both existing and planned mining operations. In recognition of the significance of this topic, MINING ENGINEERING is presenting a series of articles on tailings disposal. The first, published in June, outlined some site criteria that influence tailings disposal and some of the design options available to meet these criteria. The following article explores in more detail important design criteria for tailings dams and provides several case study illustrations.

Jan 7, 1981

By Marling J. Ankeny

MINING research in the U. S. today is indeed complex, whether it involves the Government, a small private concern, or a large one. And it promises to become more so, despite great advances already made in developing equipment and technology. The U. S. Bureau of Mines is committed to place greater emphasis on mining research as expressed in a recent policy statement to Congress on the "Long Range Minerals Program," by Secretary Fred A. Seaton, quoted above.

Jan 1, 1958

By Felix A. Vogel

Flue-dust, to most blast-furnace operators, means a troublesome by-product, the formation of which should be curtailed, if not prevented entirely. However, with the increasing use of fine ores, larger furnaces, and high-pressure blast, the production of flue-dust is constantly increasing, and amounts annually in the United States to from 3,000,000 to 3,500,000 tons, an exceedingly high tonnage, of which a large part has been discarded as valueless.

Jan 1, 1913

By R. Hogg, T. F. Dumm, L. G. Austin

The applicability of SEM/EDS techniques to particle-by-particle analysis of respirable coal dust is evaluated. It is demonstrated that the correction procedures needed to account for the failure of most EDS systems to detect light elements (especially carbon) become unreliable for particles in the respirable size range (< 10 µm). Other serious limitations arise from x-ray counting errors for coal particles with low but significant mineral content and particle counting errors for liberated mineral matter.

Jan 1, 1991

By Lyall Workman

New mines are frequently located at altitudes above 3,000 meters (10,000 ft.). Drill selection must take the altitude effects into account, to insure high productivity and good bit life. In particular, compressors must be sized differently than for low altitude operation. A larger compressor is required to deliver adequate air to the bottom of the blasthole. Many drills in remote locations use diesel engines as the prime mover. Altitude effects on engine performance should also be considered.

Jan 1, 2007