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By A. L. Engel

Many western ores containing ;old, silver, and copper can be mined and concentrated at a profit only when the recovery of those metals is high and treatment costs are low. Usually, ores containing easily dissolved copper minerals, or copper minerals that become soluble to some extent through oxidation during treatment, present a real problem in cyanidation. Copper cyanide compounds are formed that tend to 'precipitate and that cannot yield regenerated cyanide and metallic copper on contact with zinc. This results not only in some loss of copper through solution in cyanide, but in excessive consumption of cyanide above the amount required for the extraction of Gold and silver. Any moans, therefore, of minimizing the: loss of cyanide while at the same time effecting high recoveries of the several values contained in the ore is of wide interest. A sample of typical low-grade ore of gold, silver, and copper, containing copper-sulfide minerals, was obtained from the MacLaren Gold Mines Co., Cooke, Park County, Mont., for laboratory investigation by flotation and cyanidation.

Jan 1, 1950

By Peter Swanson

One of the primary methods for analyzing roof stability in underground mines is the age-old method of “roof sounding” where a miner taps on the roof and listens for the hollow sound of loose blocks of rock. This paper looks at the feasibility of using noncontact laser-based vibration measurements to detect roof fall hazards with the ultimate vision of improving, expanding and automating procedures for mine roof inspection. Vibration measurements made on loose blocks of rock in underground mines are summarized and compared to estimates of fundamental resonance frequencies for rock slabs of the size responsible for highly hazardous “skin failures.” Both laser Doppler vibrometry and full-field interferometric methods are examined and are considered to be feasible methods for detecting anomalous vibrations in loose roof rocks. Results from simple laboratory experiments using laser vibrometry demonstrate some of the proposed application concepts. While considered a challenge to move these techniques from the laboratory to heavy industrial or outdoor environments, the potential for success in the current application is enhanced by the reduced requirements of qualitative analyses.

By A. M. Ouchi

Existing empirical design tools have been developed from fair-to-good quality rock masses (RMR76 >50). This paper presents a focus of ground control research presently being conducted by the Rock Mechanics Group in the UBC Mining Department in incorporating weak rock masses (RMR76 <50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented with over 450 weak rock data points from mines such as the Stillwater mine (Montana), the Eskay Creek Mine (BC) and several mines in the Carlin Trend and other parts of Nevada. The original database is comprised of spans supported with ?traditional? mechanical bolting. In weak rock environments however, this type of support has been found for the most part, ineffective. This paper presents the span and weak rock RMR76 relationship for four different support categories. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

Jan 1, 2008

By Lloyd A. Morley

This report details the continuation of mine power systems transient research under USBM Grant G0155003. The purpose of the work, which commenced under Grant G0133077, is the elimination of safety hazards created by transients" and the objective is to provide knowledge about transients existing in a-c and d-c coal mine power systems. The report chapters cover theoretical background, instrumentation, and experimental investigations. The instrumentation discussion scans measurement problems and considerations plus the development of a low-cast peak-detector. Transient data from in-mine measurements are presented and include high-voltage distribution and d-c trolley systems. Extremely unique field exercises are described involving actual power equipment connected on the surface to duplicate typical underground coal mine system arrangements. Here, transients on high-voltage distribution resulting from vacuum circuit breaker operations could be observed under controlled conditions, and work centered around how surge capacitors effect transients. Using the in-mine and staged transient data, specific conclusions and recommendations are made with emphasis on high-voltage distribution.

Jan 1, 1977

By John R. Reeves

The development of an new industry, which must prepare its marketable products at or near the source of the raw material, and ship them to a market which may cover half a nation, is more or less influenced by a number of natural and cultural conditions such as (1) location of plants with respect to a large market, (2) climatic conditions, (3) transportation facilities, (4) labor supply, and (5) water supply. An effort is made in this pager to give in detail a number of the more important of these conditions as they affect, either favorably or unfavorably, the development of the oil-shale resources of southeastern Indiana. The utilization of the New Albany formation for the production of oil will be similar to a large scale low-grade ore proposition in which the raw material can be obtained in very large quantities at a relatively low cost. It appears, therefore, in considering the value of this shale or its economic position in relation to other oil shales, tie cost of mining and preparation for the retort are of prime importance.

Jan 1, 1923

By J. Burlin Johnson

In small-scale blasting experiments conducted in the Bureau of Mines laboratory, small charges were used to produce craters in blocks of concrete mortar. The results are compared with larger scale experiments of other research workers, and the comparison demonstrates the similarity of the results obtained and indicates that small-scale blasting should be a useful tool for predicting large-scale blasting effects. INTRODUCTION The purpose at this investigation was to conduct blasting experiments in mortar in the laboratory and then, by comparing the results with those from larger scale field blasts in rock to determine to what extent, if any, the laboratory results resemble those in the field. The work described herein was the initial phase of a project aimed at evaluating small-scale blasting as a tool for use in improving blasting techniques. It is evident from the stand-point of control and cost that small-scale blasting would be valuable in the study of rock fragmentation by blasting in mines and quarries, if the extrapolation is valid.

Jan 1, 1962

By R. H. Lien

The Bureau of Mines developed a flue gas desulfurization process as part of its goal of minimizing the undesirable environmental impacts associated with energy and mineral-processing plants. The modified citrate process involves absorption of sulfur dioxide (S02) in a buffered citric acid solution. The S02-loaded solution is regenerated by countercurrent contact with steam in a packed tower. The wet S02 product is then dried and can be liquefied or further processed to make sulfuric acid. Test data from process investigation unit studies are presented. Material balances, flowsheets, and cost estimates are given for recovering S02 from copper smelter reverberatory gas, lead smelter sintering machine tail gas, and power-plant stack gas. Operating cost estimates show the process will add $0.04 per pound of copper, $0.01 per pound of lead, and $0.015 per kwhr to the cost of the respective operations. These costs could be substantially reduced if a source of waste heat was avail-able to provide the process steam requirements.

Jan 1, 1982

By Raymond P. Maloney

The Rhyolite mercury prospect is on the south flank of Juninggulra Mountain--a large rhyolite intrusive in the Kuskokwim River region about 36 airline miles northwest of Red Devil, Alaska. Bulldozer trenching by the Bureau of Mines exposed bedrock at intervals in a 2,000-by 3,000-foot area where previous prospecting by the owners had disclosed abundant float and several in-place stringers containing cinnabar in widely varying amounts. The additional trenching indicated that the mercury mineralization in the limited area investigated was confined to erratically distributed short stringers and to small lenses, occurring in discontinuous zones in numerous silica-carbonate dikes and sills or along their altered contacts with sedimentary rocks. The geologic relationship of the mercury-bearing silica-carbonate dikes and the nearby rhyolite intrusive is similar to that existing at several other mercury mines and prospects in the. Kuskokwim region. The depth of over-burden and the presence of permafrost were serious obstacles to bulldozer trenching, and only a comparatively small part of the mineralized area was thus investigated.

Jan 1, 1962

By P. C. Van Natter

Numerous mine fires have resulted in high death tolls and considerable finan¬cial loss during the history of coal mining. In most instances the death toll and financial loss were greater because of inadequate fire-fighting facilities. The information in this report is presented in the hope it may serves as a guide in the selection, placement, and care of fire-protection systems in similar coal mines. The adequacy of fire protection varies according to size of operation, employment, and production. When fires occur on the surface or underground, measures must be applied quickly to prevent incipient fires from spreading. The record of coal-mine fires shows that, in many instances, facilities for combating fires were very meager or were absent. It would be virtually impossible to establish and maintain all the necessary facili¬ties that may be needed to extinguish widespread mine fires, but it is believed that the coal industry can ill afford less than the minimum required by other industries where the time element and avenues of escape are much more favorable.

Jan 1, 1958

By Ovsei Volberg

Motion capture involves recording the position and global orientation of joint sensors of a real object, in most cases a real person performing some human activities. This information is usually recorded at uniformly spaced instances of time, or as it is often called frame-by-frame. Then the recorded motion data sets are processed and mapped into a skeleton hierarchy of a virtual, computer simulated human figure to control the motion of the virtual human in the computer simulation. In the first part of the paper we review several new techniques developed to facilitate the manipulation, noise reduction, storage and reuse of captured data, which have a potential to reduce the overall cost of motion simulation and improve its realism. In the second part of the paper we consider the real life problem of reducing a worker?s risk from being hit by underground mining machinery in a confined space. We formulate a set of requirements to motion editing for this particular task and analyze the limitation of existing techniques

Jan 1, 2000

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

All output is saved in the file MFIRE OUT m the di¬rectory and on the disk containing the program The file can be inspected with a text processor and sent to a print¬er, if needed CONTENTS OF OUTPUT FILE The comment lines, reference temperature, air densi¬ty, a table of the units of measure for the results, and the average values are shown at the beginning of MFIRE OUT All input data will be shown in the output file if LOUT on Control line number 1 is _<-1 For each contamination source, a new branch will automatically be setup The new airway and junction ID numbers will not interfere with the original numbering scheme of the data file Next are the results of the selected simulation(s) in the following order network balancing, network balancing considering temperatures, transient-state modeling, and altered equilibrium due to fire and distribution of the contaminants. Depending upon the contents of the data file, and the simulation selected, attention, warning, and error message will be shown at locations where calculations resulted in unusual conditions

Jan 1, 1990

By Steven J. Page, John A. Organiscak

Prolonged exposure to airborne respirable coal mine dust is responsible for coal workers&apos; pneumoconi¬osis (CWP): Furthermore, miners who show evidence of higher radiographic categories of simple CWP are at increased risk of developing progressive massive fibro¬sis (PMF). As of 1990, there were nearly 130,000 coal miners in the United States. "&apos; This excludes mines that produce less than 10,000 tons annually and the anthracite coal mines. Estimates indicate that at age 58, an average of 7/1000 U.S. workers and 89/1000 U.K workers will have developed PMF(2-1) Health research studies have iden¬tified that the risk of developing and the severity of CWP arc directly related to (1) the amount of respirable dust exposure and (2) the coal rank.,&apos;- The rank of coal is its stage of formation in the series peat, lignite, sub-bituminous, bituminous, and anthra¬cite (in order of increasing rank). The rank of coal can also be represented by the com¬mercially important characteristics specified by its proximate analysis: fixed carbon, vol¬atile matter, mineral matter, and moisture content.

By Joseph E. Chilton, Robert J. Timko, Charles D. Taylor

No regular monitoring of methane is required in areas of gassy coal mines outby the mining face. Methane ignitions that have occurred in mine outby areas indicate the need to provide better protection to workers. Handheld methane monitors are now used by some miners to make periodic measurements of methane at the working face. The IYONI II gas detector which is incorporated into a miner’s cap lamp and worn on a miner’s helmet can continuously provide an alarm signal whenever methane levels exceed a set level. Tests were conducted to evaluate the performance characteristics of this methane detector by measuring response times with methane gas supplied through a calibration fixture or adaptor. Other response time tests were performed with the detector in an environmental test box. Performance was also evaluated in a full scale test gallery where face methane emission and underground ventilation were simulated. Procedures for calibration by response time measurement of the IYONI II detector have been developed. In limited testing, the IYONI II detector was found to reliably detect the presence of 1 percent by volume methane.

By Gerrit V. R. Goodman, Fred N. Kissell, Charles D. Taylor

In This Chapter [Methane emission peaks Exhaust line curtain or duct The spray fan system Dust scrubbers with blowing ventilation Dust scrubbers with exhaust ventilation The ventilation of abnormally gassy faces Methane detection at continuous miner faces Ventilation and methane detection at bolter faces and Reducing frictional ignitions] This chapter gives guidelines for preventing methane gas explosions at continuous miner sections in coal mines, both at continuous miners and at roof bolters. The need to control peak methane emissions is particularly stressed. Emphasis is also placed on ventilation principles, monitoring for gas, and reducing frictional ignitions. METHANE EMISSION PEAKS Methane emission from the coal at continuous miner faces varies considerably. Plotted on a chart, methane emissions consist of a series of peaks and valleys corresponding to the cutting cycle of the mining machine, with the methane concentration spiking as the machine cuts into the coal (Figure 3–1) [Kissell et al. 1974]. These methane peaks can be substantial. For this reason, efforts to safely dilute the methane must focus on the level of the [ ]

Jan 6, 2006

Until man was able to produce light, his working day was pretty much limited to daylight hours. Underground miners have a special problem because in a mine it is just as dark during daytime as it is at night. The first devices used for mine lighting were torches and open flame 011 lamps. Torches made from twisted grass and dipped in tallow or pine pitch would burn for a while, but they made a lot of smoke and probably went out when they were needed most. During the 15001s, miners lamps consisted of a small metal dish with a hook attached to hang it up. The saucer-shaped dish was filled with animal or fish oil and a wick made of twisted fibers was laid In the 011 and hung over one edge where it would burn. This lamp would burn longer than a torch, but the amount of light cast by the pale, flickering flame was probably only a little better than no light at all.

Jan 1, 1976

Prevent collisions between large mine-haulage trucks and smaller vehicles parked in areas not visible to the haulage-truck operator, Approach Two electronic systems were developed to detect the presence of vehicles in the blind areas of a parked haulage truck. The systems can warn haulage truck operators of presence of vehicles that are blocked from view. The systems do not apply for trucks in travel. How It Works The systems use electronic transmitting techniques-one system is based on low-frequency radio waves and the other on very-high-frequency radio waves. Each system requires that a signal transmitter be mounted on the smaller vehicle to be detected. Continuous signals from this transmitter are sensed by receiving antennas mounted on the right front and rear of the large haulage truck. Upon receiving a signal, the receiver energizes warning lights and a buzzer in the cab of the haulage truck, alerting the operator to a possible collision hazard. Detection distance is adjustable, depending upon the size of the haulage truck, but a minimum of 30 feet was the design goal.

Jan 1, 1990

To restore ventilation and prevent the accumulation of explosive or toxic gases by quickly installing substitutes for stoppings blown down by an explosion. Approach Temporarily replace blown down stoppings with a parachute-shaped brattice which can be erected in minutes. How It Works The self-sealing brattice is secured to the roof, ribs and floor by anchoring its nylon edge strip at several points using extensible poles, shads, or available projections such as roof bolts. The air pressure in the entry pops open the chute of lightweight sailcloth, forcing it tightly against floor, roof and rib. See Figure 1. This emergency brattice has been tested at two locations in the Bureau&apos;s Experimental Mine at Bruceton, Pennsylvania. In a test last December, one MESA inspector wearing full rescue apparel (including self contained breathing apparatus) installed a self sealing brattice in an entry at the Bruceton Mine. Although he did not have any previous experience with the device, he easily erected it in slightly less than 10 minutes, using two extensible supports (pogo sticks). Research to improve and refine the self-sealing brattice is continuing.

Jan 1, 1977

Improve transmission of data from an underground mine monitoring system to a remote, mass-data storage system. Background Instrumentation systems in underground mines must operate under environmental extremes of dust and humidity, local electromagnetic/radio frequency (EM/RF) interference fields, and potentially explosive atmospheres. During a recent roof-bolt study performed by the Bureau of Mines, it was necessary to transmit a large quantity of data to a data storage system. Conventional wire cable transmission presented several limitations which often required special electrical isolation or physical protection. Because conventional wire cable presented certain problems, the Bureau of Mines investigated alternative means of data transmission. The research investigation led to the selection of fiber optic cable for data transmission applications. The fiber optic method of data transmission offers several advantages: ? Since the transmission medium consists of light waves, it is safe to use in gassy mines. Where applicable, MSHA permissibility standards for peripheral devices must be met. ? It is lightweight and rugged. ? It can operate up to 131000 feet (4km) without repeaters and without EM/RF field interference.

Jan 1, 1986

By Jack C. White

The Bureau of Mines, in its efforts to insure the continued viability of the domestic minerals economy, has been engaged for several years in research on the extraction of alumina from domestic, nonbauxitic resources. Hydrochloric acid leaching of kaolin is one of the more promising technologies being studied for recovering alumina for feedstock to existing aluminum smelting capacity; 93 pct of this feedstock is currently imported either as bauxite or alumina. Organics contamination of pregnant leach liquor, originating during solvent extraction for removal of iron from aluminum chloride solution formed during hydrochloric acid leaching, causes rapid deterioration of the semihard rubber lining of process equipment. These organics were removed by a skimming tank-coalescer-activated carbon adsorption system. Organic levels of less than 10 ppm from the coalescer and less than 0.5 ppm from carbon adsorption were achieved. Analytical methods employing CC14 extraction and infrared spectrophotometry were developed to determine the organic content of both the liquor and the carbon. Mass transfer zones delineated in the carbon columns provide adsorption data for the design of larger systems.

Jan 1, 1981

By Walter J. Frank

Thls report summarizes work done under Bureau of Mines contract H0357100, "Development of a Crimp Connector for Trailing Cable Splices." The purpose of this effort was to establish optimum connector design conditions to meet flex cycle, pullout and electrical resistance criteria on phase power conductors. Field testing of "optimum design" connectors is briefly discussed. One of the primary objectives of contract H0357100 was to enable one to design better performing phase conductor connectors. Illustrating the practical significance of this 1s a discussion on the development of a new splice kit for trailing cables. The connectors in this kit were designed in accordance with the design methods described in the contract final report. Kit components, test data, and a connector installation tool are also discussed. The successful effort on the phase connector has resulted in contract H0377042, entitled "Design and Testing of Joining Sleeves for Trailing Cable Ground and Pilot Wires." The purpose of this contract (currently in effect) is to improve ground-conductor and pilot-wire performance. Significant findings to date are discussed.

Jan 1, 1979