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By W. R. Reed, D. E. Pollock, T. W. Beck, J. A. Organiscak, J. D. Potts

"In underground continuous mining operations, ventilation, water sprays, and machine-mounted flooded bed scrubbers are the primary means of controlling respirable dust exposures at the working face. Changes in mining arrangements, such as, face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation, and equipment operator positioning, can impact the ability of dust controls to reduce occupational respirable dust exposures. This study reports and analyzes dust concentrations measured by the Office of Mine Safety and Health Research for both remote-controlled continuous mining machine operators and haulage operators at ten U.S. underground mines. Results of these respirable dust surveys show that continuous miner exposures varied little based on depth of cut, but are significantly affected by ventilation configuration. Haulage operators experienced elevated concentrations in blowing face ventilation. The type of cut influenced exposures, with elevated exposures observed for both continuous miner operators and haulage operators when working in crosscuts driven into, or counter to, the section airflow. Individual cuts are highlighted to demonstrate instances of minimal and excessive dust exposure attributable to particular mining configurations. These findings form the basis of recommendations for lowering face worker respirable dust exposures when performing a variety of continuous mining cuts.INTRODUCTION Underground continuous coal mining operations may encounter a wide range of conditions and arrangements during production and development activities. These activities typically produce respirable coal mine dust, putting operators of continuous mining machines and coal haulers at risk for elevated exposures. In order to comply with federal regulations limiting respirable dust exposures for the duration of a working shift, mine operators typically implement ventilation, water sprays, and machine-mounted flooded-bed dust collectors (scrubbers) to dilute and control mine dusts during coal cutting. Nevertheless, changes in operational conditions can limit the ability of these controls to effectively reduce dust exposures. Some examples of conditions that can change during the course of mining include face ventilation configuration, orientation of crosscuts mined in relation to the section ventilation, and operator positioning. Because these arrangements are largely under the control of mine operators, any insight into associated exposures may inform future plans and behaviors, reducing occupational exposures to respirable dust. The objective of this OMSHR study is to evaluate respirable dust exposures associated with a range of continuous mining arrangements by comparing occupational dust concentrations measured during a series of field surveys. These comparisons consider face ventilation configurations, depths of cut, and crosscut mining practices."

Jan 1, 2015

By J. R. Koehler

Mining practices at the Sunnyside Mines, Sunnyside Coal Company, Sunnyside, UT, have been documented by U.S. Bureau of Mines researchers to preserve the extensive history of yield pillar-based longwall gateroad system evolution on the property. An overview of the historical mining conditions, practices, and innovations that resulted in the evolution of the two-entry yield pillar gateroad system currently employed at Sunnyside was developed from interviews of 30 long-time Sunnyside employees. Employing yielding chain pillars at Sunnyside virtually eliminates tailgate pillar bumps and contributes to reducing face bumps. Limiting the overall width of the gateroad system benefits bump control and especially, roof and floor stability.

Jan 1, 1994

By James R. Kennedy

The recent drop in world gold prices is driving many northern Nevada underground gold mines to look for new ways to improve and enhance current mining operations. Continuous improvement programs at these mines are finding the means to increase mine productivity while reducing total production cost. This paper looks at developments in the drill and blast program at Independence Mining Company’s Murray mine.

Jan 1, 1999

By H. N. Dunning

A comprehensive research program designed to aid development of new and improved methods for more complete production of petroleum from partly depleted reservoirs is being conducted at the Bureau of Mines Petroleum Experiment Station, Bartlesville, Okla. Water flooding has accounted for much of the petroleum produced by secondary-recovery methods; however, a considerable portion of the crude oil commonly remains in place after water flooding has been terminated. In recent years the possibility of increasing the efficiency of water flooding by using surface-active additives has received wide attention. In general, the results of laboratory research have shown that use of detergents as water-flooding additives will reduce the residual petroleum in porous media (1).3/ Some less extensive field tests have supported this conclusion but have not been entirely conclusive (2). Later studies (3, 4) have given conflicting evidence as to the relative worth of detergent additives for water floods in water-wet (hydrophilic) or oil-wet (hydrophobic or lipophilic) reservoir materials. The results of these studies emphasize the need for a more complete understanding of the fundamental principles involved in displacing petroleum from reservoir surfaces by injected fluids. Accordingly, a comprehensive research program was initiated to investigate the practical and fundamental aspects of detergency in petroleum production.

Jan 1, 1953

By R. F. Favreau, L. C. Lang

"In modern blasting technology blasts are designed and analysed on an energy-mass-time relationship. The energy of the explosive is derived by computer analysis and the work potential of the available energy is expressed in numerical values. The mass involved in the blast is determined by the geometry of the blast and by the rock density. Time is also a relevant parameter, because time is required to complete the three basic stages of the breakage process.For successful application of the blasting parameters the basic mechanism of the breakage process must be understood.The physical-mechanical properties of the rock, local structural geology and the thermodynamic properties of the explosives can be brought together to create a computer model of a blast with which it is possible to predict separately the results of each parameter and to express the predicted degree of change in any parameter by actual numbers.A long-range project has started to create a ""bank"" of rock properties for as many Canadian and foreign mines as possible. A computer model has been successfully applied to predicting the effect of varying the ratio of spacing to burden at constant rock volume and significantly improved results are achieved, as the S/B ratio is increased up to about 2 to 2.5.High-speed photography has been applied to determine the time that has elapsed between zero time and the beginning of movement of the mass. The results assist in determining minimum and optimum delay time required for multiple-row blasting.The approach as described in the paper is now well proven and is clearly superior to previous methods based on powder factors and human assessment."

Jan 1, 1972

By P. R. Bradley

This paper is one of a series , dealing with mining methods and costs , sponsored and published by the U. S. Bureau of Mines . Papers of this series are written by engineers and executives of mining companies , at the solicitation of the Bureau , and in accordance with an outline prepared by Bureau engineers , for the purpose of securing uniform presentation and conformable data . The property of the Alaska Juneau Gold Mining Co. is situated near the city of Juneau , Alaska , in what is known as the Harris mining district . Wholesale mining operations have been adopted on a large scale and 10,000 to 11,000 tons per day of gold- bearing ore are mined and sent to concentrators near Juneau . In addition to gold , the ore yields 0.6 ounce of silver and 13.0 pounds of lead to each ounce of gold recovered .

Oct 1, 1929

By N. B. Aughenbaugh

This report summarizes the results of an investigation into the causes of coal mine roof instability caused by the environmental characteristics of the air ventilated through a mine. The field studies, which were mostly in the Illinois Coal Basin, concentrated on collecting data of surface weather conditions, mine air characteristics (relative humidity and temperature), roof material types, roof movements, and characteristics of roof deterioration. The field studies revealed seasonal changes in weather are reflected in the mine air. The intake air undergoes rapid tempering along its course as it interacts with the ambient mine conditions. There are seasonal moisture interchanges between the mine rock and air, and a mine will lose more water than it gains on a yearly basis. The field studies also established that when the roof rock is shaley, seasonal changes in the humidity will cause roof deterioration because of the detrimental action of moisture on the shale. Roof falls were inventoried and classified by geometry. In the laboratory investigations, physical tests proved unreliable for evaluating shales for roof stability. The Franklin slake test lacks the sensitivity needed to differentiate shale durability for roof stability. A relative humidity test that reveals the sensitivity of a shaley rock to moisture change was devised. Environemntal chamber studies showed that neither temperature nor barometric pressure have a direct influence on shale durability. Photoelastic studies showed that the rate and depth of moisture absorption into a shale is controlled by bedding planes, fractures, and holes interrupting the exposed surface.

Jan 1, 1976

By A. Adu-Acheampong

Photogrammetry and laser scanning has been employed at a number of Newmont mine sites to mitigate risks associated with conventional structural mapping, determining the geometry of voids from old underground workings, and generating topography in areas of slope instability. Laser scanning has also been used to evaluate as-built pit slope configurations with respect to design assumptions, operational practices, and rock fall potential. Recently, remote sensing applications carried on an unmanned aerial vehicle (UAV) were used to generate base topography at some Newmont sites. UAV are generally more convenient and less expensive and can be utilized in areas where cloud cover prevents manned aerial photography missions. This paper discusses these applications, and provides commentary on their benefits and limitations based on recent experience.

Feb 27, 2013

By L. H. Pye

For large mining sites in the west, the traditional method for performing an ecological risk assessment (ERA) provides little useful information for risk managers faced with selecting and designing sound remedial options. Current U.S. Environmental Protection Agency (EPA) risk assessment guidance largely supports quantitative risk characterization of individual species as surrogates for population and ecosystem-level effects. Developing a work plan for investigating and remediating ecosystem-level changes potentially caused by large-scale historic mining/smelting contaminant release requires a decision process that incorporates a more holistic ecosystem management approach. Some of the most wasteful efforts associated with mine site ecological risk assessments arise when the risk analysis and data collection programs are not specifically linked up-front to the risk manager's decision needs. The following paper discusses the importance of employing a decision-based, ecosystem management framework when conducting ecological risk assessments at large mining sites. A case study of an ecological risk assessment currently being performed at a large New Mexico copper mine site is presented.

Jan 1, 1999

By M. J. Klishis

This paper presents the findings of a study on roof bolters' hazard exposure. A "micro-analysis" of accident data was combined with ergonomic observations of roof bolter operators to categorize bolting-related injuries and a checklist was constructed. Bolting-related problems were identified as situations that could expose bolter operators to hazards. Approaches to avoid these situations were applied at six mining operations to evaluate specific problems in roof bolting operations. The re-search emphasized the importance of analyzing worker behaviors in the context of mining situations and equipment design problems that lead to human error accidents.

Jan 1, 1995

By T. A. Rickard

Flaubert, as we know, laid stress on the selection of the right word, le mot juste, the precise epithet, the word that belongs to the thing. A sentence, or even a paragraph, may be spoiled by the use of a word that is not proper, that does not fit or is foreign to the meaning intended. An Australian mining expert is reported to have said: You have a property of considerable value, and what I saw warrants a good development of very rich cubicular galena, with gossan intermixed. 'Cubicular' means `belonging to a small bedroom', a `cubicle' being a sleeping compartment. He meant `cubic', of course. This is a malapropism, and reminds me of the lady from Chicago that, on her return from Europe, said how much she had enjoyed the rural parts of France, because, among other things, it was "so delightful to hear the French pheasants singing the mayonnaise to the tune of the Los Angelus". It is impossible to amalgamate coal-tar thoroughly with the pulp in the agitating-tank. In metallurgy, `amalgamate' refers to the combination of mercury with one or both of the precious metals, forming an amalgam, which is an alloy of mercury with another metal. It differs from other alloys, such as brass or bronze, in being made without the aid of heat, inasmuch as mercury is molten at the ordinary temperature. The word comes to us from the Greek. through Old French and means `something soft'. It is a mistake to use technical terms, having a specific meaning, for purposes that are foreign to that meaning. The writer of the quotation is not discussing any combination of metals; he is dealing with the physical process of mixing and is using 'amal-

Jan 1, 1931

By Sen A. K

The Chiria Iron Ore deposit falls within the well-known Horse-shoe-shaped Singhbhum-Bonai-Keonjhar belt in India, where most of the deposits supplying ore to various steel works of Steel Authority of India Limited (SAIL) and Tata Iron and Steel Company (TISCO) are located. With an estimated reserve of about 2000 million tonnes of ore (at 55 per cent Fe cut-off) spread over four contiguous blocks, it is the largest iron ore deposit in India and one of the largest in world. The present study is confined to only one of the four blocks of Chiria viz North Block, comprising an area of 2.11 km2. `Corporate Plan 2005' of SAIL envisages development of a large open cast mine at Chiria to meet its enhanced requirement of iron ore by 2001-02 AD.

Jan 1, 1995

Jan 1, 1984

By O. C. Blade, Elizabeth Hughes

Conservation in the utilization of any product is always subject to improvement if the composition and properties of the product are known. Petroleum is no exception, and knowledge of the characteristics of crude oils, even when given on the broad basis of routine type analyses has proved useful to chemists, engineers, and geologists in improving pro- duction and utilization of petroleum. For a quarter of a century the Bureau of Mines has sought to provide such information regarding crude oils and has analyzed many samples of petroleum by its standardized rou- tine method. Most of these analyses have been published, sometimes in special compilations, other times in connection with reports of research on petroleum. This report is a finding index for all analyses published up to January 1, 1948. The routine method used for all these analyses is basically the same as that described by Dean, et al.. Briefly, the procedure consists of testing by standard methods, small samples of a crude oil for gravity, sulfur, color, and viscosity, and of distilling a sample of the crude oil by a standardized procedure and determining certain properties in the sep- arated fractions and residuum. Careful records are made during the proce- dure, and the distillation data obtained are used to calculate the approx- imate amounts of products present in the sample such as percents of gas- oline, kerosine, gas oil, and lubricants. The data obtained are recorded on a standard analytical report form. An analysis of a sample of typical midcontinent crude oil is shown in table 1. Compilation of these analyses, sometimes in tabular form and usually for specific geographic areas, are published from time to time. Analyses are often shown in connection with other studies, such as engineering field reports. This bibliography is a compilation of references to 115 publications, which contain analyses of crude oils by the Bureau of Mines. References may be found to analyses of crude oils from the United States, Canada,

Jun 1, 1948

By T. Bohmer, L. Auret, N. Pillay, Z. Horn, P. Rambalee, A. Haasbroek

As part of a broader digital technology-enabled transformation programme, a major mining company is systematically implementing Advanced Process Control (APC) solutions and associated instrumentation throughout their operations. This paper highlights the approach and benefits of this holistic approach for a specific instrumentation installation, and APC installation at a South African coal processing plant. For the coal processing plant under consideration, a systematic approach was followed. Process sections/units are considered from upstream to downstream processing. APC solutions are designed for each process section and each process section is interrogated in terms of availability of sufficient process measurements to ensure stable, capable, and ultimately, optimised performance. Where insufficient process measurements are available, instrumentation upgrades are implemented. Finally, APC solutions are implemented, and evaluated in terms of productivity, safety, health, and environmental benefits. For the flotation section, an opportunity was identified to install froth sensors. The installed froth sensors provide measurements on froth velocity, bubble size, height, colour, and stability. The improved visibility that the froth sensors provided on the flotation process resulted in quick gains in terms of productivity: for example, instability in the feed to the flotation section could be quantified. This resulted in targeted process troubleshooting in an upstream thickener, and subsequent improvement of process stability, and reduced feed variance. The measurements from the froth sensors were further integrated in an APC solution. Proportional mass pull contributions per cell and per line can be inferred from the froth sensors, serving as controlled variables, while pulp level set points serve as the manipulated variables. On-off tests indicated that the advanced process control solution provided increases in yield and product quality.

Sep 1, 2021

By A. L. Irwin

THE disposal of tailing or waste material, which is generally a very large proportion of the ore treated, is a major problem in the location and operation of any concentrating enterprise and especially so where the life of the operation is expected to continue for many years. Many factors need to be taken into consideration in the selection of a tailing site, chief among which are economical handling of the material, subsequent re-treatment of the tailing, and precaution against stream pollution by waste water. The final location of many mill sites bas been governed largely by the selection of a sui table area for tailing storage. The Sullivan concentrator of the Consolidated Mining and Smelting Company is situated about three miles from the Sullivan mine at Kimberley, B.C., and one of the deciding factors in its location at this distance from the mine was the availability of a suitable area in which tailing could be deposited. In view of the indicated long life of the property, a far-sighted policy bad to be adopted in the matter of tailing storage, for not only would it be necessary to accumulate a huge tonnage of finely ground material, but also reclamation for iron recovery at some future date bad to be considered. Some idea of the extent of the problem may be grasped when it is noted that, by the end of 1938, over 18,000,000 tons of tailing bad been impounded in an area of some 200 acres.

Jan 1, 1939

By Paul M. Tyler

The colony of French Guiana ( or Cayenne ) is administered by a governor , assisted by a privy council of five members . A council - general of 16 members is elected by French citizens resident in Guiana, and the colony is represented 3 in the French parliament by one deputy . The area is about 34,740 square miles . French Guiana is the largest gold producer of the French colonies , producing nearly $ 1,000,000 worth annually . Considerable prospecting has been done on the bauxite deposits , which are extensive . Copper , iron , lead , and 4 mercury deposits are also reported . In 1931 , 10,000 prospectors for gold were reported as working . The French Government is taking an active interest and has sent a committee of mining experts to explore the region ; no permits are to be issued to individual prospectors while the committee is in the colony . Plans for development of mining industry include consideration of 4,500 convicts and 2,500 natives already in the colony and available for labor .

Apr 1, 1933

By L. S. Zhou

Germany-made AFX-100 multi-grade fluidized classifier, with exquisite built-in structure and unique novel design, materializes not only advanced and efficient classification, but also precise particle distribution and safe operation, in addition to lower energy consumption and operational cost. It, simultaneously in place of screw grader, water cyclone, and fine mesh sieve, is equipped with multi-function, and indicates superior advantage in comparison with other else grading facilities. As the third-generation equipment, which is efficient and modern, it, in China and therefore all over the world, will find wide application in processing both fine and ultra-fine iron ore resources. Industrial test, carried out in Benxi Steel?s Waitoushan Iron Mine, shows efficient classification, i.e., ?74µm particle contents in coarse, medium and fine products come to 6.09%,11.82% and 82.73%, respectively, while qualitative and quantitative efficiencies end up by 74.38% and 87.66%, respectively. Its separation efficiencies amount to 2.2 times as many as spiral classifiers, 1.8 times as hydrocyclones, and 1.3 times as vibration high-frequency fine screens. Another industrial test, which was practiced in Anshan Steel?s Donganshan Sinter Plant, indicates that classification qualitative efficiency comes to 65.06%, equal to 1.51 times as many as hydrocyclones; yield, 55.79%; -71µm particle contents in medium and coarse products, 42.02%; -71µm content in fine product, 95.42%; and concentration, 12.33%. Estimated separation indexes are as follows: Yield for concentrate at 31.22%, up 0.22% than that from general processing line; concentrate grade at 66.42%, up 1.13%; recovery ratio comes to 65.84%, up 1.28%, which, based on pilot study, results in 20 million yuan of economic return for Donganshan Floatation Plant.

Jan 1, 2014

By Rob Morrison, Peter Cameron

"Many products and technologies have been developed from outcomes of research projects carried out by the Julius Kruttschnitt Mineral Research Centre (JKMRC). When these products and technologies are applied to the design and optimisation of blasting, comminution and separation, improvements in profitability can be realised.In 1970 Alban Lynch promoted two practical ideas to improve plant operations:• Ore and equipment properties can be separated allowing experience with one type of ore or equipment to be transferred to other types of ore and equipment. If this experience was encapsulated in a mathematical model, then these properties could be combined and used to simulate (ie. to design and to optimise) complete mineral processing circuits.• Many problems associated with scale-up from laboratory to industrial equipment could be eliminated by experimental work on full-scale equipment in the plant.Many JKMRC research projects have focussed on the development of models of unit operations in mineral processing and their application to process simulation.Models of comminution and classification developed at the JKMRC have been used since the early 1980's. Ore characterisation techniques developed to support these models are licensed world wide through JKTech. The application of comminution modelling techniques to blasting, which optimises the process feed size distribution is used in Mine-to-Mill® projects. The advances in the understanding and modelling of froth flotation over recent years have provided the opportunity for integrated ore characterisation and process optimisation from resource to product.JKMRC project outcomes often provide proven opportunities for the mineral industry to improve performance and productivity. JKTech was established in 1986 to commercialise and market the most promising outcomes and thus ensure their continuing availability to the mineral industry.They include:• Commercial software (JKSimMet, JKSimBlast and JKMetAccount).• Monographs (Comminution and Blasting).• Technologies (Mine-to-Mill® and flotation optimisation).• Hardware products (JKFrothCam, JKJetLift® and the Mineral Liberation Analyser).This paper summarises these technologies and their benefits."

Jan 1, 2003

By D. W. Bacon

Plant process optimization programs are often costly, both in technical effort and loss of production. Evolutionary Operation or "EVOP" is a mode of plant operation consisting of controlled cyclical changes in process conditions by which information is provided concerning potential process improvements while both volume and quality uniformity in production are maintained. Its conceptual simplicity and low cost of utilization have led to successful adoption in a variety of industrial manufacturing operations. This paper is an expository account of basic EVOP theory, the problems encountered and the organization required in applying it to a processing plant. Illustrations are provided which indicate the payoff that can result.

Jan 1, 1967