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By MAURICE SUNKPAL, Taghi Sherizadeh, ELAHEH TALEBI, PEDRAM ROGHANCHI

Excessive heat exposure is among the health and safety hazards for mine workers. The nature of the underground climate makes it a convenient avenue for heat generation and accumulation from several heat sources, including autocompression, equipment and heat from strata. This study investigates the effects of clothing insulation and acclimation on the thermal comfort of mine workers exposed to heat in underground working environments. Several clothing ensembles were considered to analyze the effect of the thermal resistance of clothing on the workers’ thermal comfort. To investigate the impact of clothing insulation, the thermal comfort limit of an underground miner was calculated in the form of maximum allowable exposure time for an eight-hour shift.

By S. C. Sun

Very little information is available concerning the magnetic properties of minerals and only recently has there been any attempt to correlate magnetic susceptibility with varying chemical composition1. The work described here covers a study of the relationship and chemical composition of both the rutile and sphene types of titanium minerals. The relationship between the magnetic susceptibility of three selected mineral specimens and the applied field strength is also presented. Experimental: The equipment and procedures used in this in- vestigation for crushing and cleaning the mineral specimens and for determining the magnetic susceptibilities were the same as that employed by Spokes and Mitchell1. The particle size of-the measured specimens was limited to 270/325 mesh.

Jan 1, 1959

By Jacob L. Brinkman, Catherine E. Johnson

Researchers are exploring the use of unmanned aerial vehicles (UAV) to measure concentrations of gas emissions in situations where such measurements are otherwise extremely difficult to obtain, such as NO and NO2 (NOx) emissions from surface mine blasting. Recently, countries have imposed or are planning to impose surface blasting gas pollution regulations, which creates a need for an improved understanding of UAV-based gas measuring systems. The experiments detailed in this paper were performed to determine if airflow generated by the rotors, also known as downwash, unnaturally alters concentration measurements. Downwash turbulence could create locations of varying pressure, which could affect density-based concentrations as measured by some governing entities, including the Occupational Safety and Health Administration (OSHA). 

By Clifford W. Schultz

Four native copper ores, two conglomerate and two amygdaloidal, were tested to determine their amenability to sorting. One of them, a conglomerate ore from the Kingston mine, showed a high sortability as evidenced by an 80 pct recovery of copper in the minus 6-, plus 1/2-inch size range. Using the Kingston as a case example, the cost of mining and concentrating was estimated for a standard case and five optional cases involving varying degrees of sorting. This analysis indi¬cates that the production cost per pound of copper can be reduced on the order of 1 to 1-1/2 cents per pound along with a significant decrease in capital investment.

Jan 1, 1975

By F. A. Renninger

Limestone and dolomite are the most common rock types mined and quarried as industrial minerals in the United States. In 1993 over 720 million tons of limestone and dolomite valued at over 3.1 billion dollars were extracted and consumed throughout the nation. While the greatest volume of this vast production is used as aggregate for construction purposes, few people realize how critical limestone and dolomite are to our food chain and our national goals of clean air and water. Limestone, including dolomite, can truly be called nature's gift to the environment. Without a reliable, economical source of limestone the quality of our environment would be severely comprised and the standard of living of our citizens dramatically reduced.

Jan 1, 1995

By R. L. Frederking

Geological remote sensing is, "....the study of the Earth utilizing electro-magnetic radiation (EMR) which is either reflected or emitted from the land surface in wavelengths ranging from ultra-violet (0.3 micrometre) to microwave (3 metre)."1 Selected examples which illustrate a variety of successful geologic applications include lithologic mapping, 2 engineering soils mapping,3 tectonic interpretation,4 and mineral and petroleum exploration.5 This report examines the applicability of remote sensing for bauxite exploration in northeastern Mississippi. Specific objectives were to map lithologies of northeastern Mississippi from LANDSAT imagery, to determine the utility of LANDSAT imagery for delineating and mapping known deposits of bauxite, and to discover and map new bauxite deposits.

Jan 1, 1977

By T. Good

Twin roll sizers are neither compactly designed machines nor are they configured to accommodate underground mobility; in fact, twin roll sizers leave room for improvement in many aspects of the design. The DRC1200 capitalizes on the weaknesses of these machines to make a more productive, easily maintained, and compact twin roll sizer than current market offerings. These strides were made through the inception of the Hard Rock Extraction System (HRXS), which requires a mobile sizer as part of the system. After use of a third party sizer on the HRXS, potential improvements were evident. These improvements include improved structural design to reduce overall footprint and an optimized design to reduce operating cost.

Feb 23, 2014

By Roe-Hoan Yoon, Kaiwu Huang

Derjaguin and Dukhin [1] were the first to develop a first-principle flotation model by considering the role of surface forces in bubble-particle interactions. According to the model, the ζ-potentials of particles constitute the energy barriers, E12, for particle (1)-bubble (2) interactions, which corroborates well with the observation that flotation recoveries reach maxima under conditions of zero-zeta potentials. In the present work, a series of surface force measurements were conducted for the quartz-dodecylamine hydrochloride (DAH) flotation system, for which detailed studies had been conducted by D.W. Fuerstenau [2], including the measurements of zeta-potentials, contact angles and collector adsorption as a function of pH.

By WILLIAM M. CROSS, ALBERT ROMKES, BERNARDO MORENO BAQUEIRO SANSAO, Jon J. Kellar

The mineral industry uses significant amounts of water in processing. Thus, sustainable practices with the processing of ores are of critical importance. An impact tester was used to measure the adhesion force between particles and a glass disk [1,2]. A removal force was caused by the impact of the disk/particle containing a puck with a stopper. Johnson-Kendall-Roberts (JKR) theory [3] was used to determine the interfacial energy between the particles and the substrate. Capillary condensation of water can occur between the particle and surfaces in humid environments. The adhesion of particles on rough surfaces has been studied previously [4-10]. The research presented herein combines both variables to separate particle types with minimal water usage.

By D. C. White

The Vulture Mine near Wickenburg, Arizona was a major gold producer from 1863 to 1942, having yielded about 11,000 kg Au and 8,000 kg Ag. Gold occurs as coarse native metal and electrum in quartz veins and also finely disseminated within a quartz monzonite sill and its silicified wall rock. The sill is semi-conformable within a Proterozoic volcaniclastic-dominated sequence all dipping north about 35°. Early mining focused on the vein-hosted gold particularly in the immediate hanging wall and footwall of the sill. Later efforts included some open-pitting of the outcropping sill and adjacent altered and mineralized rock. Two sets of post-mineral faults have complicated the orebody geometry.

Jan 1, 1988

By James A. Berberick

Research methods to develop an economic model for the determination of regional mineral advantage are discussed. An industrial complex conceptual framework is used to study potential mineral resource outputs of Kansas. A procedure for making a comparative cost analysis of potential outputs for a Kansas-based industrial complex is outlined and illustrated. Methods for estimating aggregate demand and for developing an input-output matrix for a hypothetical limestone complex are explained. The input-output matrix is expressed in physical units. A computer algorithm for converting physical production data and input cost data into total cost per unit of output information is briefly explained and flowcharted. Limitations and usefulness of this procedure in determining regional advantages are surveyed.

Jan 1, 1969

By W. E. L. Minter

The most important witwatersrand gold placers occur on extensive unconformity paleosurfaces that were produced during protracted periods of fluvial degradation. The erosional etches on what was generally unlithified substrate indicate that low sinuosity erosion patterns prevailed. The transport systems were dominantly braided fluvial with a minor debris-flow component. The placer sediments were non-cohesive sands and gravels which were evidently transported by fluctuating, yet perennial, discharges across extensive, low relief, bra1dplains, not far from littoral environments. Progress made in understanding heavy-mineral transport processes now emphasizes the importance that selective entrainment probably had in producing concentrations. Cognizance that these characteristics are not unique to the Witwatersrand should be taken into account when designing exploration models.

Jan 1, 1988

By L. D. Hartzog

A pilot plant investigation of a semi-autogenous mill - ball mill circuit is described. The plant was operated with minus eight-inch diabase as feed material to the semi-autogenous mill. The semi-autogenous mill recycle screen underflow was put to a ball mill in closed circuit with a cyclone. An operating Work Index of 13.3 to 14.9 was obtained with the pilot ball mill. This Index is substantially in agreement with the scalped feed laboratory Work Index for 15.3 for recycle screen underflow. The Bond Index of the diabase was 15.8. Thus, one may use the scalped feed laboratory Work Index to size semi-autogenous grinding plant ball mills.

Jan 1, 1974

By E. Alan Haley

Accurate and economic control of line and grade on long tunnels, large structures, excavations and waterways, has been a problem to surveyors and engineers for decades. The conventional method of surveying, incorporating a level, transit, and a number of surveying technicians, has proven, in the past, to be a very expensive and time-consuming operation. Alignment with a laser has solved most of the problem. Figure 1. With the advent of the Perkin-Elmer Model 5620 Construction Laser, use of laser light is now both dependable and economically feasible for unlimited applications in modern construction and surveying. The laser projects a continuous, narrow red beam of brilliant light, providing a constant alignment reference, and will not interfere with operations.

Jan 1, 1968

By J. H. Elledge

Hydraulic Transportation of Phosphate Ore from, a 40,000 Cubic Yard per Day Strip Mine IMC is transporting 1500 yards per hour of phosphate ore in a water slurry a distance of approximately five miles from a strip mine to a flotation beneficiation plant at their Noralyn Operation. in Barrow, Florida. This ore, which consists of approximately 1/4 phosphate, 1/2 silica sand, and 1/4 clay slimes, is being pumped through a 20 inch O. D. pipeline using seven 20 and 18 inch GIW metal pumps direct connected to electric, motors. This paper details some of the problems involved and the specific methods used to accomplish this bulk material handling requirement.

Jan 1, 1966

By W. E. L. Minter

The most important Witwatersrand gold placers occur on extensive unconformity paleosulfaces that were produced during protracted periods of fluvial degradation. The erosional etches on what was generally unlithified sub-strate indicate that low sinuosity erosion patterns prevailed. The transport systems were dominantly braided fluvial with a minor debris-flow component. The placer sediments were non-cohesive sands and gravels. They were evidently transported by fluctuating, yet perennial, discharges across extensive, low relief braid plains, not far from littoral environments. Progress made in understanding heavy mineral transport processes now emphasizes the importance that selective entrainment probably had in producing concentrations. Cognizance that these characteristics are not unique to the Witwatersrand should be taken into account when designing exploration models.

Jan 1, 1991

By Johan M. Versteegen

During the production of silicon carbide a by-product is generated, which contains a mixture of crystalline and amorphous silicon carbide. Utilizing the difference in density, shape and surface properties of the crystalline and amorphous silicon carbide, separation tests were carried out with gravity concentration and flotation equipment. The flotation results of the fine fraction of the silicon carbide mixture were not encouraging. The processing of the coarse fraction of the silicon carbide mixture by jigs resulted in a high grade crystalline SiC concentrate with the desired specifications. The separation was largely influenced by the shape factor. An IHC-jig with a newly designed hydraulic drive was used to carry out the test program.

Jan 1, 1988

By T. M. Ruff, W. G. McCoy, M. J. Beus, S. Iverson

Monitoring conveyance position and wire rope load directly from the skip or cage top offers several significant safety and production advantages. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) developed a shaft conveyance monitoring system (SCMS). This system consists of position and guide-displacement sensors, a maintenance-free battery power supply and a new sensor, which is mounted on the wire rope with a Crosby Clip, to measure hoist-rope tension. A radio data link transmits sensor output to the hoistroom. A state-of-the-art automated hoisting test facility was also constructed to test the concept in a controlled laboratory setting. Field tests in full-size shafts are now underway.

Jan 1, 2000

By Thomas E. McNider

Preliminary studies were conducted at Jim Walter Resources, Inc. Blue Creek No. 3 Mine to determine the influence propane operated heaters exert on the mine ventilation system when two of three intake airshafts were heated. During initial use of the heaters, it was found that change in density caused by heating a portion of the air at two of three intake shafts altered under- ground air flow changes sufficient to be considered a violation of Part 75.322 of the Federal Coal Mine Health and Safety Act of 1969 as amended by Public Law 95.164. The primary concern was to accurately define the problem in order to derive a workable solution.

Jan 1, 1980

By James H. Lammers

Over the years, the chemical processing industries have con­tinued to move from batch to continuous processing in order to obtain better quality control, simpler designs, and often reduced capital and operating costs. One exception to this trend has been the carbon elution circuits in the gold industry. Although some successes have been achieved on a pilot scale, no continuous elu­tion circuit using Anglo American Research Laboratory (AARL) methods has ever been used on a commercial scale until now. This paper describes the continuous elution circuit which was recently commissioned at a major gold project. The paper also presents the economic justification for the selection of the process over conventional batch technology.

Jan 1, 1998