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By Lynch A. J

A method has been developed for the prediction of the performance of multi-stage grinding-cyclone classification circuits of any degree of complexity on any ore for a wide range of operating conditions. The method involves the simulation of the circuit on a digital computer by means of. mathematical models of the individual units. At present, to establish the characteristics of the ore and the machines in mathematical terms, it is necessary to know the performance of a simple system on the ore for one known feed rate and feed sizing analysis.Further work on the separate identification of the terms defining the characteristics of the ore and the machines may permit the method to be applied directly to the data derived from small scale tests on ores.INTRODUCTIONThe cost of preparing metalliferous ores for concentration processes by, grinding and classification frequently represents a major portion of the cost of treating such ores, and it is necessary both from an economic and a metallurgical point of view that grinding and classification circuits should be operated at their optimum efficiency. It will be realized that the processes carried out in all units in such circuits behave according to physical laws and, if a mathematical representation of the laws applying to each unit could be derived, optimization of the overall process for any given conditions of feed or product may not be difficult.The physical processes in both tumbling mills and hydraulic classifiers are extremely complex and do not appear at present to be amenable to a rigorous mathematical analysis. However, empirical mathematical models of grinding units which have been presented previously (Callcottand Lynch, 1963; Lynch and Moore, 1963) may be used to discuss the operation of the grinding units in multi-stage circuits. Another type of model, which leads to a reasonable...

Jan 1, 1965

This is the story of a blast - not a large blast by todays standards as it only involved a total of approximately 50 cubic yards of rock. Nor did this blast involve any new or revolutionary blasting technique or require involved analysis or the applications of rock mechanics theories. Instead, it was a blast that involved the tried-and-true principles of good blasting: precise alignment of blastholes; selection of explosives and detonators designed for the conditions encountered; extreme care in loading and hooking up and the use of several ingenious devices and techniques to achieve the proper loading and firing of the blast

Jan 1, 1976

By Doris Hiam-Galvez

The latest technologies that improve mining and mineral processing efficiency and significantly reduce the emissions and effluents will be briefly reviewed. In this sense, the paper point out that the water treatment using techniques such as nanofiltration through membranes to achieve purity levels equal to the incoming water supply is now possible and examples of how this is done will be presented. Membrane technology using nanofiltration can be effectively used for recovering valuable products in water from mining operations and also to remove contaminants. The resulting water is of prime quality equalling potable water standards. The technology can be adapted to most mining operations.

Sep 12, 2011

By R. L. Urie, L. Burdzinski

Non-operational mine facilities are subject to placement on the EPA's National Priority List (Superfund). Once a mine site is undergoing investigation and/or remediation, MSHA regulations for health and safety may no longer be applicable. This paper addresses the changes in the applicable and relevant standards that apply to health and safety and public health related to site contaminants. The implementation of health and safety plans, and the development of public health risk assessments are described. Examples are presented from Superfund activities at the Eagle Mine, near Minturn, Colorado; the Anaconda Smelter near Mill Creek, Montana; California Gulch near Leadville, Colorado; and Bunker Hill, Idaho.

Jan 1, 1991

By E. W. Felegy

THE need for improved mine communication to increase efficiency and to insure greater safety has long been recognized. General and unrestricted communication between all points underground, and between the surface and all points underground, is probably the least advanced phase of the mining industry. An ideal system of mine communication must re- quire no fixed wire installations. The equipment must be small, lightweight, and readily portable, and the power requirements low. A system that can be used not only under normal circumstances but also in an emergency, when the continuity of wires, tracks, and pipelines may be disrupted, must function independently of any aid furnished by standard installations.

Jan 5, 1953

By William F. Kane, Eric C. Drumm

Rock slope failures in the Great Smoky Mountains of Tennessee are a continuing problem. A study of the geotechnical factors affecting such slopes was conducted in this geologically complex region. Seven rock slopes, five of which had undergone failure, were identified and mapped. Other parameters were mapped in addition to the standard geologic and geometric parameters. These were joint frequencies across and down the slope, and surface hardness from Schmidt hammer tests. Regression analysis on the various data revealed that Schmidt hammer hardness correlates very well with joint cohesion back-calculated from failure geometries. This approach suggests an alternative means for estimating joint strength.

Jan 1, 1986

By A. A. Shook

For relatively little capital outlay, the metal delivery control system in the BHP Copper Rod Plant at San Manuel' was significantly upgraded using the UNAC process simulation and control system (CICS Automation, Newcastle, Australia). An accurate simulation of the metal delivery process was developed with UNAC, which was then used to design a robust controller capable of dealing with plant complexities such as noise, time delays, and nonlinearities. This controller was implemented online using UNAC. Thanks to the extensive preparatory simulation, the controller worked immediately and required no additional online "tuning". Operator response has been favorable, and the UNAC control system has become part of the standard operation of the plant.

Jan 1, 1999

By John E. Caffrey

The Federal Coal Mine Health and Safety Act of 1969, Title III, Interim Mandatory Safety Standards for Underground Coal Mines, is devoted to protection of workmen from hazards of electricity, roof, ribs, fire, and explosions. The Rules and Regulations, promulgated through the Federal Register, provide the criteria by which the law would be administered. Certain aspects of the law involve features that could be summarized under entrapment. These are sections 303 (y)(1), (y)(2) and 317 (f) (4). This paper is intended through the use of the figures to describe how these features of the law affect mine ventilation design, what are the problems, and possible solutions to them.

Jan 1, 1974

By D. C. Valdemeri, Oppermann J. P. Z., R. G. Schaarschmidt, C. S. Mendonca

This case study was conducted in an aggregate company, located at Estância Velha town, RS, Brazil. The study was based on the results of vibration monitoring mainly in terms of PPV (peak particle velocity) and frequency. Changes in the blasting design were performed to adjust the limits determined by the Brazilian standard NBR 9653:2005. Understanding the seismic wave attenuation for the site, changes in the blasting design were tested to fit the limits, such as reduction of maximum charge per delay, initiation orientation and sequencing and finally the replacement of accessories like "shock tube" by electronic initiation system. The results are shown below.

Jan 1, 2015

By M. Akser, F. L. Pirkle, B. W. Stratford, B. Ipekoglu

To date, no ilmenite, rutile and zircon deposits of commercial importance have been reported in Turkey. However, information from recent reconnaissance activities indicates the possibility of an economically viable heavy-mineral deposit in the vicinity of Ormanli, which is located northwest of Istanbul along Turkey's Black Sea Coast. Consequently, beach coil sand-dune samples were collected from that area for additional analysis. Laboratory methodologies drat were designed to simulate standard industrial heavy-mineral plant practices were used to analyze and evaluate the samples. Based on these analyses and current market needs, none of the deposits in the Ormanli area qualify as a commercial heavy-mineral deposit.

Jan 1, 1997

By Thomas Lautsch

After a short description of geology and gateroad roof support technology in the German coalfields the development of roof bolting as primary roof support is presented. Based on geotechnical parameters, different strategies used for roof support at depths of 3,300-4,600 ft. are explained. Strict quality management and a strict monitoring program are part of the entry development. A number of recently finished developments are described such as the introduction of standardized bolts and accelerated resin systems. An outlook of future goals is presented. The paper concludes with a comparison of roof control systems at RAG's mines in the US and Germany.

Jan 1, 2000

The general principles of technical due diligence best practice that are involved in assessing a mineral property in the early stages of its development are described and a bibliography of relevant papers is attached. The issues specific to the evaluation of gold deposits are highlighted. The Australasian Institute of Mining and Metallurgy's (The AusIMM) initiatives in this area, dealing with the proper public reporting of Reserve/Resource information (JORC Code) and property assessment/valuation (VALMIN Code), will be used as a framework against which the illegal tampering with drilling samples to artificially boost their gold content (salting) from the Busang gold deposit (Kalimantan, Indonesia), owned by Bre-X Minerals Limited (Calgary, Canada), will be reviewed. While the Busang saga was based upon fraud, through salting the samples, the general lessons to learn from such a scam are worth documenting. In Australia, most of those working in the mineral industry belong to long established professional institutes and consultant associations (eg The AusIMM or Mineral Industry Consultants Association [MICA]) that require their members to work within their technical limits and to comply with best practice guidelines, or risk being judged and found wanting by their peers in the context of strong Ethics Codes. There is also a strong interface between such representative professional bodies and the corporate and financial market regulators (ASC/ASX), which closes the monitoring loop. Canada has only now seen the wisdom of having this type of early warning system in place. Fraud and deliberate deception will be always possible, but deception on the enormous scale that occurred at Busang is most unlikely with proper surveillance systems in place and the use of accredited technical professionals. There should have been more hard data available about so big and rich a deposit owned by a C$6Bn company.

Jan 1, 1997

By Thomas H. Holley

This presentation will describe the underground excavation at the Bad Creek Pump Storage project. It consists of approximately 3,650 m of various size tunnels ranging from 4.2 m to 9.0 m finished diameter, a powerhouse cavern 45 m high by 135 m long by 22.5 m wide, and 422 m of 9 m diameter shaft. A total of 350,000 m of rock will be excavated, hauled, and placed in a submerged wier. Temporary rock support consisting of shotcrete and/or rockbolts is installed as required.

Jan 1, 1987

By A. Wahab Khair

This paper presents an analysis of surface ground movements recorded from two longwall mines in Northern West Virginia which operate in the Pittsburgh Seam. The instrumentation areas consisted of four panels, two at each mine, covering various sections with unique topographic features. Instrumentation consisted of survey monuments on 25 to 120 ft. spacing. Vertical and horizontal ground movements were measured at specified intervals to determine subsidence rate, developing and final subsidence profiles, angle of draw, horizontal displacements and associated strain profiles. A relationship between panel depth and width and the subsidence factor was also developed.

Jan 1, 1988

By Ren Bryce

The ninth annual Mineral & Metallurgical Processing Division (MPD) student poster contest was held in February at the SME Annual Conference & Expo in Minneapolis, MN. A total of 33 students presented their work at the contest. The competition began in January when the students submitted a one-page abstract for judging. In February, they prepared and presented a poster that explained their research. A panel of judges went to each student and listened as the students explained their research in five minutes. The students worked hard at their research and then set aside time to complete all the necessary steps to enter the contest. The MPD recognizes the effort required to enter and, as a result, provides monetary rewards to all participants. As in past years, there are separate levels of competition for undergraduates and graduates, and the prizes are designated accordingly. At the graduate level, first place receives $1,000, second place $500, third through seventh $200 each, and all others $125 each. At the undergraduate level, first place receives $1,000, second place $500, third place $250, and all others $125 each.

By Sam Kangwa, Thomson Sinkala

In the mining industry, drilling accuracy has a significant effect on the economy of operations. In this paper, results from the Nkana Division of the former Zambia Consolidated Copper Mines are presented. For the stope investigated, it was found that the extra operational costs alone were 462% of the planned costs! Clearly, there is more than good reason to pay attention to drilling of good quality holes.

Jan 1, 2004

By Jon A. Hummer, Aleksandar D. Bugarski, Shawn Vanderslice, Teresa Barone

A study was conducted to examine the potential of diesel emissions control strategies based on retrofitting existing power packages with exhaust aftertreatment devices and repowering with advanced power packages. The retrofit systems, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF), were evaluated individually using a US EPA tier 2 (ter 2) engine operated under four steady-state conditions and one transient cycle. The DOC effectively curtailed emissions of CO, and to some extent organic carbon (OC), elemental carbon (EC), and aerosol number concentration. The DPF system offered substantially higher reductions in OC and EC mass and aerosol number concentrations. Both, the DOC and DPF achieved reductions in the aforementioned emissions without adversely affecting emissions of NO2 and nano-sized aerosols. The strategy of repowering with an advanced system was examined using a US EPA tier 4 final (tier 4f) engine equipped with a cooled exhaust gas recirculation system and diesel exhaust fluid-based selective catalytic reduction system, but not with a DPF system. The tier 4f engine contributed substantially less than the tier 2 engine to the EC and OC mass, aerosol number, and CO, NO, and NO2 concentrations. The tier 4f engine was very effective in reducing aerosol mass, NO, and NO2 concentrations, but it was not equally effective in reducing aerosol number concentrations. The implementation of viable exhaust after treatment systems and advanced diesel power packages could be instrumental to the underground mining industry to secure a clean, economical, and dependable source of power for mobile equipment.

By Richard H. Olson

Talc deposits in the Precambrian of southwestern Montana (Beaverhead and Madison Counties) are unique within the U. S. A. in that large bodies of tremolite-free talc can be open-pit mined. All known deposits are in pre-Beltian dolomite units. The origin is suspected to be metasomatic, with the siliceous component having been contributed by an intrusive Precambrian granite gneiss. Precambrian deformation was extreme and is characterized by multiple periods of tight isoclinal folding and the flowage of less competent rocks, rather than by faulting. Post- Precambrian folding has been relatively negligible; the characteristic Laramide structure is block-faulting developed along northwest-southeast trends. The talc is thought to have been formed in Precambrian time; the high-angle block-faults probably have no significance with regard to the formation of the talc, but do tend to complicate mining operations. Tremolite-free talc ore bodies with horizontal widths of more than 200 feet, vertical depths of several hundreds of feet, and strike-lengths of as much as one-half mile are known in the Ruby Range and the Gravelly Range. Where dolomite is interbedded with tremolite-free talc in the Gravelly Range, the scale of this relationship permits the use of conventional open-pit mining methods with subsequent upgrading by hand-sorting techniques. Underground mining has been used in the past, but all current Montana talc-mining operations are on the surface. The hand-sorted ore, some of which is shipped overseas, is finely ground or micronized in roller mills and fluid-energy mills. The products are distributed both nationwide and abroad.

Jan 1, 1975

By T Mizuta, H Satoh, M Ogasawara, M Miyata, M Fukuyama

The Miocene Chichibu granitoids associated with the Chichibu skarn deposit are divided into North Body, South Body and Daikoku altered stock. Orebodies of the Chichibu skarn deposit are mainly distributed in the north-western part of the North Body and Daikoku altered stock. The North Body consists of magnetite-series granitoids ranging from tonalite to granodiorite and to monzogranite from the margins to the centre of the intrusion. The South Body consists of tonalite and granodiorite, and most of these rocks are also classified as magnetite-series granitoids. The Daikoku altered stock consists of a quartz diorite porphyry. The SiO2 contents of the granitic rocks of the North Body and South Body range from 61.6 to 70.7 wt per cent. During magmatic differentiation, Cu, As and Zn contents in fresh granitic rocks of the North Body and South Body increase with SiO2 content up to 63 wt per cent SiO2, and then progressively decrease with increasing SiO2 contents as SiO2 exceeds 65 wt per cent. Estimated pressure for the emplacement of the granitoids is about 0.5 kbars. Cathodoluminescence studies on quartz from those granitic rocks show that vapour rich two-phase fluid inclusions tend to occur in the core of quartz crystals, while halite-bearing poly-phase fluid inclusions occur in the margins of quartz crystals. The distribution of fluid inclusions suggests that fluid composition changed from low to high salinities during the growth of magmatic quartz crystals. Texture showing quartz crystals with an oval shape enclosed by radial aggregates of a mixture of fine-grained quartz, plagioclase and K-feldspar composing the groundmass of the monzogranite also suggests a pressure decrease during solidification of North Body. These findings show that high salinity fluids were present during magmatic differentiation and that Fe-Cu-Pb-Zn-Au-Ag skarn mineralisation of the Chichibu deposit was possibly associated with these high salinity fluids. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Niles E. Grosvenor

Complex underground mining problems are increasing as mining depths increase. Many of these problems have been solved mainly by unsystematized trial-and-error methods based on individual experiences. This system of solving mining problems has resulted in over-cautiousness whereby a large quantity of our mineral resources are left in the ground, or not enough caution with a resultant failure of the underground opening. From studies made of physical properties of rocks, large volumes of data have been collected as a source of finding correlation among the different physical tests or among certain rock types. Most of these studies have not produced satisfactory results because the investigator usually arrives at the conclusion that the results are too scattered to be reliable. The reasons usually given as the cause of this scatter are that rocks are nonhomogenous and non-isotropic. Similar types of poor correlation that were being obtained from compression tests in the Colorado School of Mines Mining Research Laboratory led to an investigation of a good method of making a simple unidirectional compressive strength test.

Jan 1, 1963