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By W. W. Adams

"The eighth National Safety Competition, that for 1932, conducted by the United States Bureau of Mines, was participated in by 322 mines and quarries operating in 34 States. Tables 2 to 6 show the relative standing of the various plants. Bronze trophies, known as the 'Sentinels of Safety,' which were provided by The Explosives Engineer magazine to be awarded annually by the Bureau of Mines, were awarded to five companies, each company having established the best accident-prevention record within one of the five classes into which all companies were divided, - namely, anthracite-mining companies, bituminous-coal-mining companies, metal-mining companies, operators of nonmetallic-mineral mines other than coal mines, and quarries or open-cut mines. The trophies are awarded for one year and are then transferred to the winners of the succeeding year's contest.The trophy for bituminous-coal mines, which has been in New Mexico for the past year, was won by a mine in West Virginia. The metal-mine trophy goes to New York State for the first time in the history of the contest. Previously it had been won by mines in Minnesota, Michigan, Kansas, and Oklahoma. The trophy for nonmetal mines remains for another year at Retsof, N. Y.; that for quarries and open-cut mines is transferred to a quarry in Michigan. The trophy for anthracite mines, of course, remains in Pennsylvania, as all anthracite mines in the contest are in that State.In determining the relative standing of the various companies enrolled in the competition, all mines and quarries were graded according to their accident-severity rates, - that is, according to the number of days of disability of employees on account of accidents in proportion to the number of man-hours of work done by all employees at the plant. Reports of accidents and of man-hours worked were furnished by the companies to the Bureau of Mines. These reports were carefully examined and classified to insure uniform weighting of accidents according to the number of days of disability to be charged and to insure uniformity of methods of calculating the accident-severity rates for the various mines and quarries. When the relative standing of all plants had been determined in this way, a summary of the records of the companies having the lowest accident-severity rates in their respective groups was sent to the members of a committee of award for examination in accordance with the rules governing the safety contest. The members of the committee of award were W. H. Cameron, managing director of the National Safety Council; William Green, president of the American Federation of Labor; James F. Callbreath, secretary of the American Mining Congress; T. T. Read, Vinton professor of mining engineering of Columbia University; C. B. Huntress, executive secretary of the National Coal Association; A. J. R. Curtis, assistant to the general manager of the Portland Cement Association; and A. T. Goldbeck, director of the bureau of engineering of the National Crushed Stone Association. When two or more mines within the same group operated without an accident during the year, the contest rules provided that the trophy for the group should be awarded to the plant whose record showed the largest number of man-hours worked."

Jul 1, 1933

By Marwan M. Mohammed, Hani S. Mitri, Wilfrid Comeaul, Baoyao Tang

In many parts of the world, rockbursts have become a major problem of mining at depth. As orebodies are being mined deeper, rockburst phenomena have become familiar to deep hard rock mines. Rockbursts are generally characterised by sudden release of energy in a volume of highly stressed rock, which can cause local violent failure of the rock mass around the opening. One method of controlling these failures is to precondition the rock mass by detonating fully confined explosive charges at the appropriate locations. This method known as destress blasting, was first tried in the deep South African gold mines (Roux et al., 1957), and was widely used later in Canada, United States, France, Poland and Japan.

Jan 1, 1999

By Melvin I. Esrig

Lime Cement column stabilization of soft clay and sand in Salt Lake City, Utah and in San Francisco California is described and discussed. Stabilization permitted the construction, in a single stage, of a 14 m MSE wall on "medium" clay in Salt Lake City. It was used to mitigate the potential for liquefaction in San Francisco and to stabilize the Young Bay Mud beneath the BART extension to San Francisco Airport. These applications are described and the field measurements of performance are reported.

Jan 1, 2000

The small-scale surface mining operation in northern regions is typically located in a remote, ungaged basin. With the recent increase in the economic potential of mining, the number of small operations is increasing. The year-to-year variability in precipitation in this region under study is of great concern to mine operators. Some years may yield only 5 to 6 inches of precipitation, while others may yield in excess of 15 inches. Such variability makes placer mining operations difficult to plan, since low water years may result in too little run-off for gravel washing and high water years may result in flooding of mining developments. There are no official streamfloaw records in many watersheds in the northern region containing placer mining claims. However, information from other streams permits calculation of an estimated discharge for a watershed under consideration using average flows per square mile of drainage. It is to be emphasized that these are average or expected figures in reality, one water year may be significantly wetter or drier than another. This high variability of annual precipitation is significant in relation to placer operations because of the large quantities of water required for this type of mining. Some operations can not operate in low water years. In the larger watersheds, operations may continue in low water years but at a slower pace because of longer water collecting times. The high variability of available run-off rakes placer mining in many parts of Alaska difficult to plan on a long range because of the unpredictability of water supplies.

Jan 1, 1985

The U.S. Bureau of Mines conducted a series of laboratory tests in a full-scale model to determine the respirable quartz dust capture efficiency of an irrigated-filter collection system while testing different filter densities, different filter materials, preconditioning water sprays, and wetting additives in the spray water. Impactor samplers were operated upstream and downstream of the filter unit to determine overall dust collection efficiency. The impactor filters containing the 0.7-to 4.7-J.l-m size fractions were analyzed for quartz content, and these data were used to calculate quartz dust collection efficiency. The results of this testing indicated that (1) increased ftIter density improved quartz dust collection, but also resulted in a significant increase in pressure drop across the filter, (2) an alternate synthetic filter material improved dust collection without increasing pressure drop, (3) preconditioning sprays mounted in the system ductwork can have a beneficial effect on dust collection, and (4) additives to the spray water did not significantly increase dust collection.

Jan 1, 1990

The works recorded in this Test Report have been performed by Rade Roncar - Electrotechnical Institute of Zagreb, SFR Yugoslavia in collaboration with Bureau of Mines. The main objective of these investigations was to investigate the possibility of fabrication of thin-walled square enclosures of satisfactory safety factor in accordance with requirements of effective technical regulations. The results and the investigations can be divided in three main fields: - investigations of thin-walled enclosures with the view of determination of pressures causing technological deformations before performing tests in accordance with effective applicable regulations, - finding the safety factor by means of tests of metal-foam pressure vents, - comparison of enclosures with and without pretreatment by technological deformation.

Jan 1, 1987

By F. Freme

Coal production in the United States reached a record level in 2005, ending the year at 1.03 Gt (1,133.3 million st) according to preliminary data from the U.S. Energy Information Administration (Table 1). Production in 2005 was 19.2 Mt (21.2 million st) higher than the 2004 level of 1 Gt (1,112.1 million st) and surpassed the prior record set in 2001 by 5.1 Mt (5.6 million st). Although total U.S. coal consumption rose in 2005, not all coal-consuming sectors had increased consumption for the year. Coal consumption increased in the electric power sector by 2.2 percent and declined in the other industrial sector, while coking coal consumption decreased slightly.

Jan 1, 2006

By J. A. Eisele

The Bureau of Mines conducted bench-scale cyclic tests to determine the composition of recycled leach liquor in the Bureau?s proposed clay/HCl leach/ HCl sparge process for producing Al203 from clay. The data developed from these tests make it possible to synthesize leach liquors for predetermined steady-state operating conditions when conducting large-scale crystallization tests. The results of two sparge tests were compared. One was a 20-cycle test with a 36-pct-HCl concentration in the mother liquor; the other was a 10-cycle test with a 26-pct-HCl concentration in the mother liquor. The effect of impurity concentrations in the leach liquor on the purity of aluminum chloride (AlCl30?6H20) crystals was determined, but there was poor correlation between this data and results that have been obtained from miniplant-scale work.

Jan 1, 1980

Provide optimum visibility of mining operations while maintaining protection and comfort for ma-chine operators. Approach Cabs and canopies with hydraulically powered variable-height control were developed for several machines and tested in underground mining operations. How It Works From his position in the cab, the operator can raise or lower the cab, selecting a height that offers either more visibility of the working place or greater clearance for tramming. The entire cab enclosure moves up and down on guide rollers that ride on a pair of rails, and is actuated by a hydraulic cylinder controlled from within the cab. Normal working heights, for each of the four different cabs developed, are with the cab bottom from 6 to 8 inches above the mine bottom. A typical range of elevation (excursion) afforded by this design is shown in Figure 1.

Jan 1, 1978

Introduction Research has shown that when an emergency occurs, work-ers often do not get the information they need to take appropriate action. Important information about incidents is either not com-municated effectively or not at all to those affected by the event. The "Emergency Communication Triangle" safety talk focuses on the content of emergency warning messages. It presents a procedure using mental cues that can be used by senders and receivers of emergency warnings. The talk includes graphics for use during the presentation, as well as references for more information. Background Interviews with 48 miners who had escaped one of three different underground mine fires revealed that warning information provided to them was inadequate. Either insufficient information was provided to miners inby the fire areas or they failed to ask the questions needed to let them plan and execute an effective escape. Most of the miners who evacuated from these three mines did not have information that would allow them to make decisions about efficient escapes. The communication breakdown came from two directions: (1) the individuals providing the warning did not offer details about the situations even though some were known and (2) the individuals who received the warnings did not ask for clarification of the situation. The lack of information allowed miners to continue attempting to place cues into normal frameworks after they should have evaluated the situation as abnormal and threatening. The uncertainty created by the lack of information influenced their decision-making and therefore their actions. Approach Researchers at the NIOSH Pittsburgh Research Laboratory have developed a training intervention that can be used by senders and receivers of warnings during a mine emergency. This material was developed for use in short safety training sessions such as start-of-shift safety talks. The information can be presented in about 15 minutes. Although the illustrations were taken from the underground coal mining industry, the training can be tailored to any work setting by substituting appropriate examples. How It Works During the safety talk, miners learn about the six categories of critical information that should be provided during emergency communications: Who, Where, What, Miners, Event, and Response. • Who: When reporting an emergency or receiving a warning, the first thing a miner must do is identify himself or herself. This is important because people react differently based on who gives them information. • Where: Giving or finding out the location of the problem is important. Of the 48 miners interviewed about their escape, only 2 knew where the fire was located. However, this information was known by either the dispatcher or the person who discovered the fire. • What: Miners must tell or ask exactly what is happening. At one mine fire, miners near the phone heard the message to evacuate and went to gather the others on their crew. One worker shouted to a machine operator: "Come on down to the mantrip. We're going out." Because it was close to quitting time, the machine operator thought they were just leaving the section a little early and went through his normal end-of-shift routine, wasting valuable time. After giving or obtaining the three initial pieces of critical information, miners can then give or obtain details about the response in progress. • Miners: Is anyone hurt? Has everyone been accounted for? When and where was a missing person last seen?

Sep 1, 2004

By Lisa A. McDonald

The environmental compliance process affects all aspects of hardrock-mining operations, from exploration through post-closure. The primary components of the environmental compliance process are requirements under the National Environmental Protection Act of 1969 (NEPA) and the permitting requirements associated with various other federal, state and local laws. This study considers the Greens Creek Mine and the development of two other projects (Alaska-Juneau & Kensington). These mines were used as the foundation for a case study of the impacts of the environmental compliance process on hardrock-mining activity in Southeast Alaska. The case study presents the institutional and legal requirements, followed by a discussion of the impact of this process on the production and timing of the three mines. The results of this preliminary study reveal some interesting findings, some expected and others unexpected, regarding the impact of the permitting process on the exploration, development and (proposed) operation of the three mining projects in the Juneau area. Determining the cost of compliance with these requirements is an important step in evaluating the appropriate course of action to protecting the environment while providing the necessary raw materials needed for society. This preliminary study highlights the initial starting point for such an analysis.

Jan 1, 1992

By R. K. Agarwal

In this paper, a new technique developed to analyze two-dimensional nonhomogeneous models is described. A simple three-layered medium with a circular hole centrally located in the intermediate layer is considered. The layered sheet is loaded uniaxially perpendicular to the stratification. The Young's modulus of the intermediate layer is lower than that of the outer layers. The stress distribution around the circular hole in a stratified medium is significantly different when compared to the case of a continuous homogeneous medium. The distribution depends upon the ratio of the height of the intermediate layer and the hole diameter. A comparison of stress distribution and procedures for preparation and testing of the model are given. The potential of the technique is outlined. In the process of applying the techniques of stress analysis to problems of rock mechanics, the recent discernible trend has been to postulate highly idealized models of physical situations. As new techniques have been developed, more complicated models have been conceived to simulate mote accurately the physical environment to which the analysis results are eventually applied. In this investigation, a new technique is developed to analyze two-dimensional nonhomogeneous models. The technique is used to determine the stress concentration around a circular hole in a soft material overlain and underlain by a hard material. In mining practice, such situations arise commonly in coal deposits and frequently in bedded or vein-type metallic mineral deposits. DEFINITION OF THE PROBLEM A plate, consisting of three layers with a circular hole in the intermediate layer, is loaded uniaxially, Fig. 1. The variable in the experimental investigation is the height of the intermediate layer, H. The diameter of the hole, D, is kept constant. The stress concentration factors around the periphery of the hole, for various values of H/D, are evaluated using the technique of photoelasticity, Table I. TECHNIQUE OF EXPLORATION Photoelastic analyses of composite models have hitherto been limited to the study of lap and butt joints between glued metals and dissimilar materials.1-3 In mining, Haber and Oudenhoven used composite models to study the stress distribution around a circular hole in two-layered media and the behavior of elastic liners in shallow underground openings.4-5 They used the stress freezing technique devised by Dally et a1.6 The procedure used in this investigation is outlined below: Casting of Layer A: Flat sheets of plastic were cast in a silicon-coated mold using Araldite 502 with hardener 951 in the ratio of 100:8 by weight. After

Jan 1, 1969

By Yeonuk Choi, Gus Van Weert

"In regular CIL circuits, activated carbon is used for two purposes: avoiding solid/liquid separation after cyanide leaching, and minimizing gold losses in the tails. The carbon distribution and gold profiles in the successive CIL stages are operating variables, not objectives. When the CIL feed contains a preg robbing constituent however, such as native carbon, there will be competition for gold cyanide and this conflicts with minimizing of losses of gold to CIL tails. This paper examines some of the limitations of activated carbon in CIL circuits handling preg robbing Carlin Trend ores.INTRODUCTION Carbon-In-Leach (CIL) has been a great success treating regular gold ores, but the technology is still challenged by preg robbing feedstocks. Little information is available in the gold milling literature on CIL gold extraction from “free” milling gold ores which are preg robbing, or on autoclave discharge (POX’ed) slurries of double refractory ores. Neither feedstock is readily available for experimentation. No literature reference could be found describing deliberate modifications to CIL operations or CIL circuits due to the presence of two types of carbon: “native” and activated. There is some literature on the gold cyanide adsorption activity of native carbons (Schmitz, Duyvesteyn, Johnson, Enloe & McMullen, 2001). Various tests have been devised to measure this activity, commensurate with CIP and CIL practices (Tretbar, Arehart & Graves). In this paper, the term “native” carbon indicates (severely) preg robbing carbonaceous materials found in gold ores. There is considerable literature on the gold cyanide adsorption activity of man-made “activated carbons”. Various tests have been devised to measure this activity, commensurate with CIP and CIL practices. These tests are comparative, i.e. results relate to a standard carbon and depend on the test methodology and carbon history. The test results are equilibrium oriented, hence of limited value to CIL circuit designers or plant operators handling preg robbing solids; in CIL circuits most carbons are not loaded to capacity. Information on gold cyanide adsorption and desorption kinetics might be more relevant and that is one subject explored in this paper."

Jan 1, 2012

Severe whipping of shuttle car trailing cables occurs when the car stops suddenly or reverses direction. This causes cable damage, and can seriously injure personnel near the cable. FMC has contracted with the U.S. Bureau of Mines to design, build and demonstrate a reel control system that will significantly reduce or eliminate whipping. II. CONCLUSIONS Results of engineering effort show that the following conditions are primarily responsible for the whipping problem. Causes may exist individually, or in combination.

Jan 1, 1972

By C. Garcia, J. J. Opazo, A. Potulsha, T. Comi

"Sierra Gorda SCM is a joint venture partnership of KGHM International (owned by KGHM SA, Poland), Sumitomo Metal Mining and Sumitomo Corp. (Japan) operating in northern Chile. The Sierra Gorda openpit mine and coppermolybdenum processing plant will become one of the largest mines in the world. The need for optimum production efficiency and sustainability has driven the creation of the most modern, wellinstrumented mine in Chile. This article contains a general review of the project including geology and history.This was a fast-track project going from greenfield site acquisition to mill startup in 10 years. Highly experienced and motivated engineers and technical staff have overcome many significant challenges resulting in a rapid ramp-up of production capacity. A potential expansion to double the production rate in the fourth year of operation has also been intensely studied.The Sierra Gorda property is located in the Atacama Desert of northern Chile, in the District of Sierra Gorda, Region II of Antofagasta, Chile (Fig. 1). There is almost no precipitation in this area. The mine site is generally flat with some rolling hills. The project is located about 5 km (3 miles) from the village of Sierra Gorda at an elevation of approximately 1,700 m (5,600 ft) above mean sea level. The village is near a highway and railway line. The city of Calama, home of the famous Chuquicamata Mine, is located about 60 km (37 miles) northeast of Sierra Gorda. In addition, the SG mine is in the midst of numerous other mines including Spence, Esperanza, Mantos Blancos, El Tesoro, Lomas Bayas, Gabriela Mistral, El Abra, Radomiro Tomic and Escondida, to name a few.The primary organizational value at Sierra Gorda is "Zero Harm." This includes employees, contractors, the environment, the community, plant facilities and mine equipment. A cornerstone of this program is called 5X5S (five by five S), which combines the lean principles of 5S with the safety model of taking five steps back and thinking about the task at hand for five seconds, five minutes, the time it takes to assess and manage the risk. "People caring about people" promotes proactive engagement in the safety of coworkers and others at work and at home."

Jan 1, 2014

By Randall M. Wheeler

Using Computer software to analyze and interpret blast vibration effects has never been so practical. Fully digital seismographs and powerful desktop and portable computers have led to the development of fast and easy to use analysis software. This workshop will focus on new Microsoft Windows-based blast vibration analysis programs developed by White Industrial Seismology, Inc. The Windows point and click graphical environment is ideal for developing full-featured and yet intuitive software.

Jan 1, 1994

By J. S. Hansen

To improve mine safety, the Bureau of Mines has conducted a search for better materials and systems to anchor roof bolts. This report describes a study on the ability of a gypsum-based anchoring medium to withstand short- and long-term loads. Results showed that 2-ft-long bolts anchored with gypsum that was injected as plaster slurry at a 0.370 water-cement ratio and cured for 10 min sustained pull test loads equal to the ultimate strength of the bolt steel (about 37,000 lb). For comparison, the minimum required capacity is 17,600 lb. Long-term loads of 15,500 lb were sustained with estimated 10-yr movement of less than 1/2 in. Two-foot-long bolts anchored with gypsum installed in a cartridge in which the water was contained in tiny capsules sustained a pull test load of about 30,300 lb at a 0.319 water-cement ratio and 10-min cure time. At a 0.288 water-cement ratio, load capacity was about 37,000 lb. The lower load capacities of cartridge-installed bolts resulted primarily from the remnants of the water-wax capsules. Above 10,000 lb, creep movement of cartridge-grouted bolts appears excessive, but longer bolts may be capable of resisting creep better.

Jan 1, 1985

By E. Niehuis, J. Y. Kim, H. G. Cramer, S. L. Chryssoulis, K. G. Stowe, C. Bendel

TOF-SIMS was used to detect, identify from parent molecular ions and determine the relative concentrations of collectors sorbed on the surface of mineral particles in concentrate and tailings samples from three Canadian concentrators. In the Kidd Creek Zn circuit, sphalerite lost to tailings carried on average a quarter of the amount of isobutyl xanthate present on that recovered to Zn concentrate; amyl xanthate, which is not reported as added to the circuit, was also detected on floated sphalerite and pyrite. At Brunswick, sphalerite particles lost to the scavenger tailings had ten times less amyl xanthate and isobutyl xanthate than those recovered to the Zn final concentrate, while both xanthates were detected on sphalerite floated to the Cu-Pb cleaner circuit. At Matagami, significantly more isopropyl xanthate and isopropyl dithiophosphate were detected on sphalerite recovered to the final Zn concentrate than on that lost to the Zn rougher tailings

Dec 1, 1995

By H. Sevim

The utilization of high sulfur Illinois coal by utility plants has been decreasing since the enactment of 1990 Clean Coal Air Act Amendment. Illinois coal producers can make their coal saleable by offering the choice of taking the combustion by-products from the utility plants and placing them in the abandoned sections of their mines. To be competitive, however, coal producers need to select an environmentally acceptable transportation-handling-placement system through which the cost-per-ton of by-product disposed can be minimized. In this paper, a few such systems are presented. The favorable operating range of each system is determined in terms of distance and tonnage. A case study is given whereby cost analysis is conducted for an underground coal mine receiving by-products from two Illinois utility plants.

Feb 24, 1997

By Felix A. Vogel

Rutile concentrate, used in the manufacture of welding rode, smoke-screen chemicals, and alloys, is being produced by the Titanium Alloy Co. of Arkansas at its mine and. mill in Magnet Cove. The company estimates a substantial reserve of recoverable rutile. This is a new operation, and production figures are not known. Previous operations had stripped the placer material, leaving the underlying mineralized zone. INTRODUCTION This report describes the mining and milling; operations of the Titanium Alloy Co. of Arkansas. The property was examined by the author on March 4, 1942, and subsequent dates. J. A. Wood, general manager, was very helpful in supplying information.

Jan 1, 1944