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By A. Iannacchione

Major Hazard Risk Assessment (MHRA)1 is used to help prevent major hazards, e.g., fire, explosion, wind-blast, outbursts, spontaneous combustion, roof instability and chemical and hazardous substances, etc., from injuring miners. The structured process associated with MHRA helps to characterize the major hazards and evaluate engineering, management and work process factors that impact how a mine mitigates its highest risk. The National Institute for Occupational Safety and Health (NIOSH) studied the application of this technique to US mining conditions through a field-oriented pilot project. Risk assessment teams used in the pilot project were primarily composed of mining company personnel. Ten case studies were performed over a wide cross-section of mines. These mines were representative of the important mining commodities in the US minerals industry, i.e. coal, metal, non-metal, and aggregate. Also, the sizes of the mines ranged from small to large and were located across the country. The ten case studies demonstrate that most US mines have the capability to successfully implement an MHRA and that the MHRA methodology produced additional prevention controls and recovery measures to lessen the risk associated with a select population of major mining hazards. The basic ingredient for a successful MHRA is the desire to become more proactive in dealing with the risks associated with events that can cause multiple fatalities. A successful outcome is marked by a thorough examination of existing prevention controls and recovery measures. When pressed to consider more controls to further mitigate the risk, a well-staffed risk assessment team was able to identify additional controls. For these mining operations, it was important to add additional controls, even if they were not required by existing mining regulations, to lower the risks associated with the major hazards under consideration. If a mining operation is not willing to commit its best people to an MHRA or will not provide them with sufficient time to see the process through to its conclusion, the MHRA output may prove to be useless. Additionally, if a mining operation is not prepared to discuss its major hazards in an open and honest fashion and to present the findings of the risk assessment in a written report, the MHRA output will be unclear, and attempts to monitor or audit important controls may not be possible. A MHRA is most effective when the mining operation possesses 1) a proper understanding of its hazards, 2) experience with informal and basic-formal risk assessment techniques, 3) proper facilities, machinery and equipment, 4) suitable systems and procedures that represent industry Best Practice, 5) appropriate organizational support with adequate staff, communications and training, 6) a formal and thorough plan for emergency response, and 7) a safety risk management approach that is promoted and supported at all levels of the organization.

Jan 1, 2008

"Gravity concentration remains the main separation method for fine iron ore and is used extensively for treating various minerals. Gravity concentration methods separate minerals of different specific gravity by their relative movement in response to gravity and one or more other forces, the latter often being the resistance to motion offered by a viscous fluid, such as water or air (Wills, 2006).Spirals concentrators are one of the gravity concentration equipment used for beneficiation of minerals. Spirals are typically used for processing of fine minerals (-1mm) size fraction. The main operating variables for a spiral concentrator are the feed rate, the solids concentration, the wash water addition and the position of the cutters or splitters used to separate the tailings, middling and concentrate streams (Sadeghi, Bazin & Renaud, 2014).The aim of this study is to investigate the effect of feed rate, solids concentration and wash water on grade and recovery on iron ore material. The Multotec SC20HC/7 WW spiral was used for the experimental test work. The spiral was tested at varying solids concentration and feed rate. The wash water rate was also varied to establish the best washing rate. The splitter positions were kept constant. Optimization of these variables is expected to provide optimum conditions for a good compromise between grade and recovery.INTRODUCTIONSpiral concentrators are simple low energy consuming devices that separate minerals mainly on the basis of density. Spirals are widely used in mineral processing as a method for preconcentration and have proven to be metallurgically efficient and cost effective.Spirals have a wide application, they are used in iron ore processing, coal, gold, chromites, mineral sands, glass sands, and in soil cleaning.Separation on a spiral is achieved through a combination of forces that act on particles as they move down the trough of the spiral. The main forces known to act on the particle on a spiral are the gravitational forces, centrifugal force, hydrodynamic drag, and lift and friction forces (Kapur & Meloy, 1998). Apart from the forces acting on a spiral, the properties of the slurry flowing on a spiral including, solids concentration, feed rate and wash water also plays an important role in the separation on the spiral.The relationship between separation efficiency and feed rate was shown to be linear, with a decrease in efficiency at higher flow rates. Previous work on flow profile by Holland - Batt (1990) indicated that any increase in the feed rate to a spiral results in a greater part of the additional flow volume reporting to the outside of the trough. The flow on the outside of the trough becomes energized and consequence to that the heavy particles find it hard to settle and escape this region to the inner region. This effect has a high impact on recovery of heavy minerals, since any increase in volumetric flow on the spiral is not made available for recovery in the inner region of the spiral."

Jan 1, 2015

By A. M. Cummings

Each mining district presents different problems as to the methods of ore extraction cad underground support, which are dependent upon the type of the ore deposit and the character of the inclosing rock. Mining costs, however, depend largely aeon the efficiency with which the methods employed underground are [applie] as well as upon the selection of the method best adapted to the physical conditions. The purpose of this paper is to present to the operator in other districts a detailed description of ho mining method used ins results obtained in tie exploitation of the bedded magnetite deposits of the Mineville district. The town of Mineville is situated in the Adirondacks, five miles west of Port Henry on Lake Champlain.

Jan 1, 1928

By Albert J. Phillips

SEVERAL important changes have been' made during 1933 in the compilation and distribution of technical literature to those interested in nonferrous physical metallurgy. The Institute of Metals, of Great Britain, announced that preprints of all its papers would be distributed monthly to all members in combination with their bulletin of abstracts. The A.I.M.E. has announced that it will distribute to all members of the Institute of Metals and Iron and Steel Divisions a monthly bulletin entitled Metals, which will carry preprints of all publications of interest to the members of these two divisions. The American Society for Steel Treating has declared its intention to change its name to the American Society for Metals in order to indicate the broader scope of its activities. The abstract service of Metals and Alloys has been improved and expanded, covering practically the entire field of metallurgical literature. These changes and innovations now provide unparalleled reference service entirely in the English language.

Jan 1, 1934

By Ronald S. Conti

This U.S. Bureau of Mines (USBM) report describes various fire-fighting resources available to the mining industry and examines the fire preparedness of four western coal mines. Information regarding fire-fighting equipment indicates that an inadequate maintenance program may cause component failure of fire extinguishers, damage to waterhoses is usually a result of improper care, and foam may be a convenient means of conveying water to the fire. Performance data relative to water nozzles (throw distance) and specific practices to improve the state of preparedness in many of these areas are discussed. Studies also indicated that a high-expansion foam plug, will travel down an entry, with a 1% rise in elevation, 207 m (680 ft) before a plywood stopping separating the generator and plug failed. The advance rate of the foam plug decreased when the entry is dry, requiring more foam concentrate and as the foam spread further down the entry. An examination of the mines showed state-of-the-art monitoring systems were common at the minesites. Fire safety was also stressed, including early detection and rapid response of the miners to evacuate the mine. However, the mines placed little emphasis on performance of water nozzles, or personal protective clothing for the underground firefighters.

Jan 1, 1994

By T. Holmes, J. Middlemiss

"Agnico-Eagle (AE) has been operating their Kittila Mine in Northern Finland since 2008. The mine has experienced considerable ore flow problems with ratholing, bridging and freezing in their mill feed bin since start up. In the first winter of operation, the entire central portion of the contents of the cylindrical flat-bottomed 2000 tonne mill feed bin froze. Flow was erratic and could only be achieved through small diameter ratholes. To maintain a reasonable, albeit limited, feed to the mill, the bin had to be kept less than ½ full and a portable steam generator was brought in to melt the frozen agglomerates that frequently blocked the outlets. The combination of limited surge capacity and frequent outages required the crushing plant to operate 24/7 and resulted in inconsistent production levels and high operating costs.AE had planned to expand the processing plant to increase throughput by about 30% when they transitioned from open pit to underground ore. These plans presented an opportunity to improve the material handling.To avoid the problems experienced with the original mill feed bin, AE enlisted Jenike & Johanson Ltd. (J&J) to test samples of the ore, and based on the measured flow properties to provide design recommendations to ensure that the new mill feed bin would operate reliably. The new 2000 tonne expanded flow mill feed bin and apron feeder were installed in 2014 and are now supplying almost 93% of the total mill feed with the remaining coming from the original bin.IntroductionIn early 2009, AE engaged J&J to visit their then recently opened Kittila mine and mill in Northern Finland (Figure 1). Over the first half-year of operation, production had been restricted in the ore handling and storage system by flow problems such as ratholing, bridging and freezing including blockages of chutes and hoppers as a result of frozen fines buildup and large frozen agglomerates. AE wanted to increase production in the existing open pit mine and mill feed operation and also wanted to avoid similar ore handling problems when they commissioned the new underground mining system under development at that time."

Jan 1, 2017

By Donald Giroux

This report documents the design, fabrication, testing, and coal mine demonstration of a hopper-feeder-bolter during a four-phase program for the U.S. Bureau of Mines. The machine was designed to increase productivity and safety in under-ground room-and-pillar mining. It performed well as a hopper-feeder for continuous haulage during a coal mine demonstration. Testing in a simulated mine showed that the machine also has good roof bolting capability.

Jan 1, 1987

By J Q. Cooper

The New Zealand rail authority, Kiwi Rail and Auckland Regional Transport Authority (ARTA), are jointly planning a new mainline rail link between Auckland’s downtown Britomart Station and the existing Western Line at Mt Eden. In 2009, APB&B, a consortia of Aecom, Beca, Parsons Brinkerhoff and Hassell Architects where commissioned to develop the conceptual design, Assessment of Environmental Effects (AEE) and business case for the new 3 km rail line towards preparing a Notice of Requirement to protect the route through Auckland’s central business district.This paper describes the engineering challenges in the development of the conceptual design for the three proposed underground stations, the running tunnels and connections to the existing network. Feasible alignment and station location options were developed and evaluated using multi-criteria analysis based on key client functional requirements, constraint mapping and environmental impacts. The resulting preferred scheme was then developed to a conceptual design suffi cient for assessment of environmental effects, risks, and the development of a robust construction methodology to allow high level capital cost estimates.The paper describes some of the major challenges overcome to develop the concept, including steep gradients, narrow street envelopes with existing buildings and structures, the need for large platform spaces with low ECBF rock cover and complex connections at Britomart and the main line near Mt Eden.The development of the conceptual design of the underground stations in particular demonstrates the need for a holistic value engineering approach to satisfying the architectural and functional requirements, in a highly constrained dense urban environment and at lowest practical cost. The construction methodology was a key input to the conceptual design development throughout.The conceptual design will be used as the fundamental basis for the development of the AEE and business case for the project in the future.

Mar 8, 2011

By George C. Branner

This circular is concerned with eight nonferrous scrap metals as they generated, collected, prepared, and consumed in California. Brief reference also is included with respect to Nevada and Hawaii. Four of these scrap metals - copper, lead, aluminum, and zinc - are of major importance and make up about 95 percent of the total value, whereas the remaining four - antimony, magnesium, nickel, and tin - make up the remaining 5 percent. For convenience, the subject matter is divided into three parts, (1) Data with respect to the collection, preparation, and marketing practices that are common activities to all the nonferrous scrap metals; (2) separate discussions and statistical data with respect to each of the eight nonferrous scrap metals in California; and (3) data with respect to Nevada and Hawaii.

Jan 1, 1962

By John Paul Gries

This Bureau of Mines report reviews the mineral industry of the Black Hills area, including Butte, Custer, Fall River, Lawrence, Meade, and Penning- ton Counties, S. Dak.; and Crook, Niobrara, and Weston Counties, Wyo. It includes discussion of geological occurrence, processing, and potential of 27 commodities that have been produced from the nine-county area. The value of mineral production exceeds $70 million annually. Gold and petroleum account for two-thirds of the total, followed by clays, cement, sand and gravel, and rock. The combined mineral industries annually consume 268 million kilowatts of electrical energy, 933 million Mcf of gas, and 2 million barrels of fuel oil. Water consumption is about 10,000 gallons per minute. About 2,700 persons are employed on a year-round or significant part-time basis.

Jan 1, 1974

By John W. Buch

Upon review of German World War II mining practices and equipment for planning coal, the Federal Bureau of Mines initiated research leading to the development of a pneumatic planer for anthracite. The results of tests are reported in this manuscript. It was demonstrated (1) that hard anthracite can be planed and (2) that the design and operating requirements are within the limits of present-day engineering and technology. For hard anthracite, the depth of cut indicated is 4 to 6 inches; with a chain pull of 20 to 40 tons and the speed of planer travel of 18 to 20 feet per minute, a 40-hp. motor will be required for the planer hoist. Compressed-air requirements for the planer will be 250 to 300 c, f, m, at 60 to 70 p. s, i. It was learned that the length of the 4 individual sections of the planer should not exceed that of the individual troughs of the armored chain conveyor (5 feet in this instance); otherwise, bottom coal will be left in synclines, and the planer will override the conveyor at anticlines. Pneumatic pushers should be operated from a separate compressed-air line fitted with a pressure regulator. Results indicate that additional development work is warranted.

Jan 1, 1957

By R. M. Winslow

"The phosphorus content of an iron ore is a determining factor as regards the value of the ore and also its metallurgical treatment. If some method of treatment, such as concentration, leaching, etc., could be used and the phosphorus con- tent of the ore reduced, it would be an important advancement in the iron mining industry towards the utilization of high phosphorus ores. Large bodies of material toe high in phosphorus to be marketable under present conditions would be made available, and a great deal of ore from the Cuyuna Range and other places, which is relatively high in phosphorus but otherwise suitable for making spiegel, could be reduced in phosphorus content sufficiently to permit its use in furnaces producing speigel.The form in which phosphorus occurs in iron ore is a much disputed question and it probably varies with the type and location of the ore. The statement has been made that ore piles on long exposure to the atmosphere often decrease in their phosphorus content. (Emmons, S.F. - Ore deposits, 1913, p. 652; Leith, C.K., Mesabi iron bearing district, U.S.G.S. Monograph 43, 1903, p. 275) There is described below experiments on the leaching of iron ores high in phosphorus, to determine whether it was economically possible to reduce the phosphorus content appreciably by leaching. As the research had a practical as well as a theoretical application, only low concentration of acids and alkalies were used.A number of variables were tried, among these being: (1) The solvent used, (2) strength of the solvent, (3) volume of solution used, (4) time ore was agitated (5) type of ore, and (6) screen size of the ore. The amount of ore taken was kept constant."

Jul 1, 1921

By George Wilkinson

"AbstractThe consistent relationship between the availability of electrical energy and our economic wellbeing is well known. As we develop the energy we need to nurture industrial civilization in decades ahead, we will at the same time reduce our reliance on dwindling supplies of oil and gas. Coal and uranium will be developed as our major fuel sources to meet medium-term. energy needs, followed by fusion and solar energy for the long term.IntroductionTHIS PAPER treats the matter of energy in a way that is quite different from that of the crisis-type atmosphere which surrounds so much of it currently in the news media. On the one hand, we lift the whole subject of energy out from its present-day involvement with short-term issues and take an important longer-term look at the solutions which lie before us. On the other hand, we recognize that short-term issues are important and, as we are reading and hearing, many of the right short-term solutions continue to elude our politicians, our policy makers, and even some of those with knowledge and authority in the energy field.A year ago, if you asked people how they would go about conserving energy, they would probably have said turn out the lights. They would probably say the same thing today, but they might also include other things such as driving the automobile more slowly or putting more insulation in the attic. However, their first impulse is still to use less electricity."

Jan 1, 1977

By Paul Averitt

The coal-bearing rocks in Iowa occur in an arcuate belt across the central and southern parts of the State (fig. 1) at the northern end of the Western Interior coal field. Coal beds of minable thickness are sporadic throughout this area and are mined principally in the three districts indicated by dark shading on the index map, although coal occurs also in the areas indicated by light shading. The coal is mostly of high-volatile C bituminous rank in all parts of the State. SURFACE FEATURES The coal-bearing rocks in Iowa are concealed for the most part by a covering of glacial drift ranging in thickness from a few feet to several hundred feet. This covering has been dissected to form a gently rolling upland, rising from an elevation of 466 feet at the mouth of the Des Moines River to about 1,200 feet in Calhoun County in the central part of the State. The local relief, however, rarely exceeds 150 to 200 feet.

Jan 1, 1949

By G M. Young

IT IS most appropriate that this first Memorial Lecture should be given in the Province of Quebec, near the site of the first metallurgical industry in Canada. At La Forge, about seven miles north of Three Rivers, iron was produced in 1783. We are told that the early settlers obtained most of their iron-ware -stoves, kettles, axes and ploughshares -from this smelter, with its foundry and forge. The Canadian copper industry also had its beginnings in Quebec when, nearly 100 years later, in the 1880's, several small copper smelters were erected in the Eastern Townships. Later, in 1899, Canada's first aluminum smelter was built at Shawinigan. From these small beginnings has grown a vast metals industry, the export value of its products being only exceeded by that of our forest products -newsprint, pulp-wood and lumber. As we are not a large country in terms of population, our domestic capacity to consume is often small in relation to our developed capacity to produce.

Jan 1, 1963

By Merwin H. Howes

In constructing the NORAD Combat Operations Center, controlled blasting techniques were employed to achieve smooth walls and to avoid shattering the rock beyond excavation lines. Extraordinary measures were taken to stabilize the rock to permanently preserve the openings. Rock stabilization was accomplished by means of reinforced concrete and gunite linings, rock boltings, installation of chain-link fabric, and epoxy resin and cement grouting. A particular zone of weakness at B vital location was supported by exceptionally thick reinforced concrete lining, rock bolts, and cement grout.

Jan 1, 1966

The Nak?azdli First Nation and the municipality of Fort St. James are located in the Stuart Lake/Nak?al Bun area and are not unfamiliar to mining. These northern British Columbian communities have been associated with the historic Pinchi Lake Mercury mine and today are closely linked with British Columbia?s newest mine, the Mt. Milligan mine. Prior to the construction of Mt. Milligan, community health and social service providers were concerned about potential impacts that would occur from new mineral development activities. This concern has led to a partnership between the above communities and researchers with expertise in the area of mining and health. This paper describes: the current mining and health environment with a focus on British Columbia; mining trends in the Stuart Lake/Nak?al Bun area; the current community-based health research project funded by the Vancouver Foundation and the Canadian Institutes of Health Research, and; a suite of community-based health recommendations to mining companies on key issues to consider when developing projects near municipalities and Aboriginal communities in Canada, based upon one of the newest mines under development in Canada.

Aug 1, 2013

By W. I. Nissen

As part of its program to provide technology for reducing undesirable environmental impacts of mineral processing operations, the Bureau of Mines developed the citrate process for desulfurizing industrial stack gases that contain from 0.1 to 2 vol pet S02. In this regenerable flue gas desulfurization (FGD) process, S02 is absorbed from cleaned and cooled industrial flue gas with a citric acid-sodium citrate solution. The absorbed S02 is subsequently reacted with H2S to precipitate marketable elemental sulfur and regenerate the solution for recycle. Laboratory investigations of process parameters provided information for designing larger scale continuous operations. Information gathered from operation of two pilot plants, one at a copper smelter and one at a lead smelter, confirmed the laboratory results. Data were obtained for design and construction of a commercial-sized demonstration plant at the George F. Weaton Power Station, Monaca, PA. A preliminary operation of the plant was demonstrated, under a cost-sharing Bureau-industry contract. This bulletin describes the citrate process and gives results of the laboratory, pilot plant, and demonstration plant studies, as well as corrosion investigations.

Jan 1, 1985

By Mark J. Zdunczyk

"Frac sand is industrial silica sand much like glass, foundry, filtration and blast sand. The sand must meet certain specifications set forth by the industry that consumes the product. The production and consumption of frac sand has experienced record growth in the last 10 years because of new oil and gas drilling, new horizontal well drilling, multi-stage fracturing and the stimulation of older wells that have little or no production. Frac sand is needed to “prop open” the fractures in the rock reservoirs to allow oil and gas to flow out more freely.According to the U.S. Geological Survey (USGS), the estimated production of frac sand in 2015 was 71 percent of the total production of industrial silica sand or 67.4 Mt (74.3 million st). This is a decrease of about 12 percent from 2014. However, the silica sand industry and other industry sources estimate only 50 Mt (55 million st) of frac sand were produced in 2015. In recent years both the USGS and industry studies have been very close in estimating the production of frac sand but with the recent downturn in frac sand production, perhaps, reporting to the USGS was not as accurate. These discrepancies may be that the USGS statistics are based on voluntary reporting by the industry and some companies report their approximate production, others may not. It is always difficult to obtain accurate production figures of any industrial mineral or construction aggregate operation as most companies tend to keep those figures somewhat confidential. It is certainly accurate to report that the production of frac sand had decreased since the last quarter of 2014 and through 2015. The oversupply of oil and natural gas has led to this decline in frac sand usage. Oversupply has idled drilling rigs and well completion activities. World Oil Magazine reports that 2015 was the worst year for rigs in a quarter century. The only wells being completed are those that have contract agreements to do so, others have been capped. Very few new wells are being drilled. Since about 98 percent of well completion is sand and water, the sand supply has caught up with the demand. There are some bright spots in the “oil patch” as the Permian Basin in Texas and the Woodford Shale in Oklahoma have kept pace somewhat with drilling and completion. It has been reported that the frac sand producers in the Brady-Voca, TX area are producing to nearly capacity. The northern frac sand producers like those in Wisconsin, Illinois and Minnesota are feeling the downturn because of the cost of shipping sand to these moderately active basins and plays. The “rule of thumb” is that freight is 2/3 and sand is 1/3 the cost."

Jul 1, 2016

By J. H. East, D. Harrington

Fires in metal mines have resulted in some of the worst disasters in American mining history insofar as loss of life is concerned. One fire caused the death of 163 miners and individual less spectacular fires have cost the lives of scores of workers. Metal mines are often very deep, and the men working on numerous levels far removed from direct communication with the surface. In many instances they cannot be warned quickly of an emergency or a mine fire by telephone or other usual method of communication, or by messenger, flashing lights, gongs, sirens, or whistles. Telephones are not paricularly effective as a means of warning unless placed at all strategic points and with attendants always on duty; though telephones well placed have a definite value in any well-pla.mied emergency procedure in mines of all kinds. Messengers are slow and men working in remote parts of a mine would not receive a warning quickly enough. Most metal mines are not electrically lighted, except at or adjacent to shaft stations and in principal haulageways, and this limits the effectiveness of flashing lights. Electric gongs and sirens or whistles have been tried as warning signals, but the sound is quickly deadened and does not travel upward into the stopes, especially those of an extensive volume. Shutting off the compressed air is by no means satisfactory as a warning, as not infrequently it is stopped accidently, so that it loses its value as an alarm. The introduction of water into compressed air lines is undesirable as a fire warning and necessitates considerable care, especially in deep mines; pressure-reducing valves must be provided to reduce pressure that otherwise would break connections or split the pipe. A quick, effective method of warning miners underground of the existence of an emergency requiring them to leave the mine immediately, such as a fire on the surface or underground, is provided by the introduction of stenches in the compressed-air lines. This method of warning is by no means experimental, inasmuch as it has been used successfully for many years in

Jul 1, 1943