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By D. Diering

Having agreed to perform this task, I naturally started to wonder what on earth I was going to talk about, and on reviewing the literature I was surprised at how little I knew and how much I?d forgotten about the origins of this industry. For example: ?I?d forgotten that the Chinese invented black powder at least 1 000 years ago, back in the 10th century (although some say this invention occurred 2 000years ago). ?I didn?t know that Roger Bacon was the first person in the Western World to give exact directions for the making of gunpowder in 1242 and to understand its potential. Pepper?s Playbook of Metals quotes:?...above all, he is named as the discoverer of gun-powder, a material which has brought more wonderful changes in the great family of man than the most potent elixir that could have been devised to prolong life?.

Jan 1, 2000

By J. P. McGee

The Bureau of Mines is doing research and development work on a coal-fired gas turbine plant initially developed by the Locomotive Development Committee, (LDC) of Bituminous Coal Research, Inc. The Bureau is redesigning the turbine blading and some of the auxiliary equipment, and is reerecting, the plant at the Morgantown (W. Va.) Coal Research Center. The present goal is a 1,500-hour run at virtually the same operating conditions used by the LDC in their final 1,100-hour test with the turbine. This will allow the Bureau to properly evaluate the new blade design. Erosion of the turbine blades (particularly the roots) by ash in the hot gases from the combustion of coal was the most serious problem in extended operation in earlier experimental work. New blades made of Stellite6 are being fabricated for the stator and rotor, and armored wear strips of titanium carbide will be inserted in the blades at the areas of probable maximum ash velocity and concentration. The trailing edges of the rotor and stator blades are being thickened and thinned, respectively, to induce the ash to travel to the casing and prevent it from returning to the base of the rotor blades. The first stage rotor and second stage stator blades are being removed to provide an annular space for maximum quantities of coal ash to centrifuge to the casing. Additional blades will be added to most of the rows in the stator to stop secondary flow of dust-laden gas toward the rotor. A contract has been awarded for fabrication of the new blades. The 1,500-hour run will be started as soon as the new blades are installed.

Jan 1, 1962

By J. S. Megahan

This report covers the design, fabrication and testing of the first and second generation mechanical scaling bars for more safely removing loose rack from mine roofs and walls. Included are discussions covering a survey of mine conditions and presently used hand scaling bar types as well as the design, fabrication and testing of the first and second prototype.

Jan 1, 1982

By Charlie Adcock, Rob Farnfield, Andy Wetherelt

The ISEE Blasters Handbook gives guidance on the level of air overpressure likely to cause occasional window breakage (151dB) and general window breakage (171dB). A long-term safe level of 140dB is also suggested. This guidance is widely used by demolition and other contractors to assess damage zones in the region of explosive applications employing unconfined charges. Other reference material gives more detailed guidance relating to window area, aspect ratio and glass thickness. Despite the guidance given in these references, complaints by members of the public regarding window breakage continue to be received by explosives engineers from air overpressure levels well below the longterm safe limit. Such complaints are not limited to the use of unconfined charges but can even be generated from the highly confined use of explosives in quarry blasting. This paper describes a series of experiments with explosive charges fired in unconfined conditions close to various window configurations. The aim of the work was to test the existing guidance levels and to extend the knowledge base in this area. Topics covered include the role of differential pressure across windows in the walls of an enclosed space such as a room.

Jan 1, 2006

By T Atchison

The Vale Ferro Carajßs S11D project in northern Brazil is based on the movement of unprecedented volumes of waste and ore for mobile in-pit crushing and conveying or ætrucklessÆ systems. In peak years, the system is intended to handle a combined 160 Mt of material.The planning and implementation of the first such system for Vale, in a remote greenfield site, utilising the services of a range of international study, design and supply partners has provided a unique set of technical and project delivery challenges. The lessons from these are of value to the industry as the trend to remote and high-volume operations continues.This paper describes the key features of the mining system and documents the challenges and mitigations for important technical, cultural and project delivery issues that have arisen. It is a combined description of the journey taken by both Vale (as owner) and SKM (as delivery partner) over the course of many years.CITATION:Atchison, T, 2013. Lessons from the S11D truckless mining project, in Proceedings Iron Ore 2013 , pp 177-184 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By N. Z. Jovanovic

Irrigation of agricultural crops may be a cost-effective option for the utilization of gypsiferous minewater as it may also create an opportunity to produce crops during the dry winter season on farm sin South Africa, such as in Mpumalanga. In this study, intensive field monitoring systems were developed and implemented to assess the feasibility and sustainability of irrigation with gypsiferous mine water. Soil water and salt balance components, as well as crop yields, were monitored in field trials carried out at Kleinkopjé and New Vaal Collieries (Anglo Coal), and at Syferfontein (Sasol). Field measurements indicated that high crop and pasture yields can be obtained, provided fertilization and irrigation water management are appropriate. Soil water and salt balances indicated that considerable amounts of minewater can be used and considerable masses of salts can be removed through precipitation of gypsum in the soil profile. With appropriate management, water and salt runoff and salt leaching can be intercepted, thereby minimizing the impact on groundwater. The SWB model is being validated through on-going monitoring. This will allow the use of the SWB model at other sites to predict the long-term impact of irrigation with mine water on soil and groundwater, as well as to run scenario simulations in order to recommend sustainable management of irrigation with minewater.

Jan 1, 2004

By Pefer F. Stacey

This paper considers some of the trends in slope design technology that are emerging as we approach the 21st Century. While the ability to design stable slopes has unproved greatly over the past 20 years, trends towards steep short-term slopes for small highgrade orebodies, and very high slopes for mega-pits centered on low grade deposits are starting to indicate limitations in available technology.

Jan 1, 1994

By Charles M. Keenan

THIS PUELICATION lists and provides brief accounts of the major disasters not classified as explosions of gas or dust that have occurred in the cod mines of the United States from the earliest times to the present. Together with an earlier publication of the Bureau2 it provides information on all the known major coal-he disasters (disasters causing five or more deaths) in this Nation's history. Sources of each account are given individually. In each account the actual words of the original publication are used unchanged, but sentences or paragraphs referring to details that are not significant have been omitted. In those few cases where conflicting data were reported in different publications the selected version is the one that appears most logical and which in general is in agreement with most of the other accounts.

Jan 1, 1963

By Ken Mills

A program of stress change and roadway deformation monitoring was undertaken to measure the forward abutment load distribution about a retreating longwall panel at Dartbrook Mine. The results of this monitoring allow roadway conditions observed at various stages of mining to be ranked according to the estimated vertical stress they have experienced. This ranking also provides a means to predict and visualise future roadway conditions at various stages of mining. This paper presents the results of the monitoring and describes the approach developed to predict future roadway conditions. The monitoring results show the vertical stress distribution associated with the front abutment from a longwall goal decreases exponentially away from the goaf edge. The vertical stress distribution peaks at the goaf edge at 5 to 6 MPa stress increase and decreases to 1 MPa within 50 m becoming imperceptible beyond 100 m By scaling this measured distribution to reflect the loading environment, the vertical stress can be estimated for different overburden depths and different stages of mining. Photographs of roadway conditions at particular vertical stress levels provide a way to visualise roadway conditions at various stages of mining in the future

Jan 1, 2000

By George H. K. Schenck

In this decade of the 1.970's it is forecast that eight billion cubic yards of rock will be excavated from 400, 000 miles of new tunnels, drifts and other underground workings in the western world, according to estimates in a report of the Organization for Economic Cooperation and Development (OECD). It is expected that the cost of this work will be in excess of $54 billion in constant 1970 dollars. Most of this underground excavation will be in mining -- 97% of the tunnel length and 89% of the volume - -the balance in construction. In addition to this huge excavating task, in the 18 developed nations of OECD, will be projects in the Communist Bloc and in the developing nations. Underground excavation requires the successful completion of three principle activities: A. Break -- to free rock from the solid work face. B. Remove-- to clear the work area of broken rock. C. Support -- to assure stability of rock surrounding the underground excavation and to eliminate risk of rock collapse. In today's fully mechanized excavation systems, continuous miners, roadheaders or tunnel borers, (A) break the rock loose from the face, and (B) remove broken rock with their mucking devices and load it onto belt conveyors, mine cars, trucks, or any other appropriate haulage system for disposal. Such operations contrast to the more complex, intermittent systems employed when

Jan 1, 1974

By John Watson, Tom Treleaven

This guide presents nur-nerous patterns that provide 8 millisecond separations between initiated charges. The guide is tabulated in seven sections to provide Quick reference by number of decks or bunch blasting. The pattern IS presented in the section where the highe!$ number of decks works. It should be noted that patterns applicable to multipledackshwtings are alsoapplicsblefor fewer decks.

Jan 1, 1995

Jan 1, 1998

By Y. P. Chugh

This is the final report of a study done by IIT Research Institute for the Bureau of Mines to identify the problem areas and technological inadequacies in noncoal (metal, nonmetal, stone, and sand and gravel) mining and processing systems that are the primary causes of death, injury and occupational disease, and to make recommendations to improve safety and health in these operations. The findings and recommendations presented in the report are based on: (1) analyses of MESA injury and employment data for the period 1961-70, MESA fatality reports for underground noncoal mines (1968-72) and lost time accident data for 1970-72 obtained from mining and processing operation: (2) visits to a variety of noncoa1 mines and mills throughout the country to observe the operations and to study the safety organization and practices used in the industry and (3) interviews with industry and government representatives knowledgeable in the field of noncoa1 mining and processing safety and health. The report provides a comprehensive overview of safety and health problems.

Jan 1, 1974

By Thomas V. Falkie

The purpose of this work was to investigate the rate at which coal is delivered from the underground working face by gathering arm type loaders as employed on continuous mining machines, to identify the factors -- geometrical, geological, mechanical, or procedural which affect the delivery rate, and to develop quantitative rate descriptive equations for the loading function. The mathematical techniques employed were factor analysis and multiple linear regression. It was determined that the coal-cutting function of the continuous mining machine is the factor that primarily influences the loading function. The geometrical factors -- the dimensions of the work area in relation to the dimensions of the mining machine - were the factors of secondary influence. Fifty-five percent of the experimental variation in the loading function was explained in terms of the six most prominent independent variables. It is expected that this work will be useful in operations-research studies as applied to underground coal mining, and with refinement will enable mine planners to select equipment based on the operating characteristics of the equipment and the mining conditions.

Jan 1, 1972

By James P. Sloss

A PERMANENT assay office is commonly established as part of the general plant equipment of operating gold and silver properties, but during the development stage of a mine, the cost of such an office is usually so assay work must be done elsewhere. In most instances only a few samples will be taken each day, but if the mine is to be developed scientifically, the analyses of those samples will guide further development. Under such circumstances, the time element in assay returns is important, since the lapse between the taking of the samples and the receipt of results may determine the success or failure of a small-mine operator. The following description of fur-

Jan 1, 1935

By T. L. Joseph

The Bureau of Mines gas been studying the blast furnace for a number of years and has published detailed reports on various phases of its investigations. Inquiries frequently received for information of a more general character than that given in the detailed reports have promoted the preparation of an information circular to cover in a general way the important features of the Bureau of Mines blast-furnace investigations. SHAPE AND DIMENSIONS OF FURNACE The modern blast furnace approximate a refractory-lined steel cylinder about 90 feet in height and 25 feet in diameter. It actually consists of a number of cylinders and truncated cones superimposed upon each other. The shape and dimensions of a modern furnace are shown in figure 1. The bottom section, commonly referred to as the hearth or crucible, is a cylindrical section about 12 feet high. Liquid metal and slag collect in this part of the furnace and are withdrawn at regular intervals; iron is removed at a level about 2 feet above the bottom of the furnace and slag at a level about 5 feet higher. Depending upon on the size of tie furnace, 40,000 to 75,000 cubic feet of preheated air per minute is introduced through from 10 to 16 tuyeres equally spaced around the periphery of the hearth.

Jan 1, 1934

By S. H. Lorain

This paper briefly describes the principal commercial and near-commercial deposits of gold-bearing gravel and the important placer-mining operations in Lemhi County, Idaho. It is on of a series on western mining districts being published by the Bureau of Mines. This paper is based on a field survey of the placer-mining districts of Lemhi County in the summer of 1938. Available information concerning gold-bearing gravels was obtained from prospectors and claim owners; operators supplied the data on mining operations. No attempt was made actually to test the gravels. The principal object of the examination was to indicate placer areas worthy of further investigation by prospective operators.

Jan 1, 1939

By David C. Benson

This Bureau of Mines report is an update of IC 8725 and comprises tables listing the name, location, and other pertinent data concerning certain fuel-related projects. The tables include information on projects involving the proposed or planned development of fuel resources, as well as the development of storage, transportation, and conversion facilities; the report covers the 26 States east of the Mississippi River. Of the total 535 projects for which information is provided, 429 concern coal mines and electric generating plants (including Energy Supply and Environmental Coordination Act (ESECA) coal conversion notices).

Jan 1, 1978

Continuously monitor and record respirable dust levels underground by a reliable, sensitive, and fast-response device. Approach A light-scattering photometer, having a LED (Light Emitting Diode) light source and other significant improvements, has been designed and incorporated into a portable continuous monitor. How It Works The monitor continuously draws air into the sampling inlet through a cyclone that removes dust particles larger than respirable size. The dusty air enters the photometer vertically downward through a cylinder which is intersected by the optical system. (This cylinder appears as a circle in the drawing of the photometer.) The center of he column of dusty air intersects a beam of pulsing light from the LED, causing some of the light to be reflected, scattered, and refracted. Only the light that is scattered at an angle of about 700 from the light beam passes through a lens to the photodetector which generates an output voltage Signal proportional to the dust content in the air. This signal is detected, amplified, and converted to a digital readout directly in milligrams of dust per

Jan 1, 1979

By L. E. Lynd

Ilmenite concentrates prepared from beach and dune sands of Florida, India, Australia, and other localities deviate to varying degrees from the theoretical composition of pure ilmenite, and generally contain more TiO2 than the formula FeTi03 would indicate, and some Fe2O3. This variation in composition is due to different amounts of altered ilmenite in the concentrates. (') The alteration has been shown to take place by oxidation and leaching of the iron in ilmenite, to yield residual products consisting of amaphous or very finely crystalline titanium dioxide and ferric oxide. Other studies(2) have stressed that ilmenite may alter first to an amorphous titanium-iron oxide, or to an amorphous mixture of titanium and iron oxides, with later alteration to crystalline titanium dioxide. There has been some speculation as to whether alteration of ilmenite is usually caused by weathering or by hydrothermal pr0cesses.(3,4,5 Three main methods of approach were used to study the mechanism and rate of ilmenite weathering. (1) Etch tests were used to learn the relationship between crystallographic orientation and the rate of chemical attack on ilmenite. (2) Altered ilmenites in New Jersey sands were compared with ilmenite in rocks of the area from which the sands were probably derived. (3) Experiments were carried out to determine at what rate, and by what agents, originally fresh ilmenite could be altered in the laboratory under simulated weathering conditions. ETCH FIGURES ON ILMENITE CRYSTAL PLANES A rather large ilmenite crystal from Sannidal, Norway, about 11/2 x 11/2 x 2 inches, bearing a few natural faces with imperfect surfaces, was prepared for etching by grinding and polishing crystal planes whose Bravais-Miller indices (referred to hexagonal axes) had been determined by X-ray methods to be 00.1, 10.0, and 10.2. Metallographic examination showed that the crystal was homogeneous, and uniform in orientation, except for the presence of twin lamellae which were oriented with their broadest surfaces parallel to the 00.1 planes of the large crystal. Since ilmenite is rather inert to standard etch reagents, strong solutions of hot sulfuric acid and cold hydrofluoric acid were used. Preliminary tests established that better etch figures were obtained using HF than with H2So4 solutions. The etch figures produced on 00.1 and 01.0 planes of ilmenite by etching 3 to 5 minutes in cold concentrated HF solution are shown in Figures 1, 2, and 3. The figures on 00.1 are "etch hillocks", rather than pits, and according to Honess(6), this phenomenon

Jan 1, 1961