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By Iain Finnie

This report is in three parts. The first part presents a review of theoretical models which have been developed to study removal operations for various types of materials. In the second part, a brief summary is given of coal cutting research. The majority of this work has been carried out in Britain using chisel type bits rather than the conical picks which are in general use in this country. However, a comparison of specific energies measured for conical picks in the laboratory and in the mine shows very encouraging correspondence. In the third part of the report, analytical models for coal cutting by picks are suggested. An extension of the British "tensile breakage" theory, developed for chisels, is given for picks. The role of crushing and cutting in coal removal is discussed as a theory which combines the two processes is shown to give reasonable predictions for specific energy requirements. Finally, directions in which the existing theory could be improved are presented and the need for further research is emphasized.

Jan 1, 1977

By Gerhard Braüner

The present knowledge on ground movements and mining damage is mainly based on observations made when mining seamlike deposits. The studies, rules, and regulations in different countries agree in that the differential ground movements, especially the strain, account for the damage to structures. Accordingly, large buildings are particularly susceptible. The opinions on what amount of ground deformation induces what degree of structural damage are not quite uniform. Mining damage can be reduced or prevented by structural and/or underground precautions. The latter comprise measures for generally reducing the ground movements (leaving pillars, filling, partial extraction) and for reducing temporary movements (rapid extraction, specially arranged workings). Because the differential movements decrease with increasing depth of mining, safety pillars are largely dispensable at greater depths. Shafts are mainly affected by the vertical derivatives of rock displacements, but extraction in the vicinity of shafts is feasible even under difficult conditions. The theoretical concept of the ground movement process established in part 1 of this work is in qualitative agreement with the facts herein observed. As a quantitative approach, it should be applied to calculating ground surface movements rather than rock movements about underground openings. It can be extended by introducing more detailed strata characteristics.

Jan 1, 1973

By Helene Kennedy, Josef Macsik, Yvonne Rogbeck, Gregory Makusa, Göran Holm

"Constructions activities in cities often imply large volumes of surplus material which could be treated by stabilization for re-use in new geotechnical constructions. Modification of dredged sediments by e.g. stabilization/solidification (s/s) is an example of sustainable handling option implying dredged contaminated sediments to become a potential resource for civil engineering constructions. The SMOCS project (Sustainable Management of Contaminated Sediments) within the Baltic Sea Region Programme 2007-2013 has developed a guideline based on a sustainability approach free to download at www.smocs.eu. The paper presents key issues in the guideline and highlights the importance of performing a field test as part of the design process. Two field tests with s/s-treated dredged sediments for new port areas are presented. Strength, permeability and leakage properties of s/s-treated contaminated sediments make beneficial use in geo-constructions possible. The influence of possible physical/chemical deterioration processes on the durability has been studied showing that freeze/thaw cycles might degrade the monolith of s/s-treated sediments. Consequently s/s-constructions shall be below freezing depth. Other deterioration processes such as salt and sulfate penetration were found of minor importance. Research is on-going to study the influence of and how to cope with freeze/thaw cycles on the long-term properties.BACKGROUNDConstructions activities in cities often imply large volumes of surplus material which could be treated by stabilization for re-use in new geotechnical constructions. The mechanical and environmental properties of the contaminated sediments could be modified through the stabilization/solidification method (s/s method) and provide a potential resource for civil engineering constructions. The SMOCS project (Sustainable Management of Contaminated Sediments) within the Baltic Sea Region Programme 2007-2013 has developed a guideline on management of contaminated sediments based on a sustainability approach. A field test on the application of the stabilization/solidification method for treatment of dredged soft contaminated sediments was implemented in the Port of Gävle, Sweden. The treated sediments were beneficially used as fill material in the new port area replacing ending natural resources."

Jan 1, 2015

By M Bettison, R Wright, N Taylor

The primary mine planning focus during early study phases of future mining projects is Life of Asset ore production and grade quality, this will always be the situation. While waste schedule optimisation is generally considered in the latter study phases nearing execution for a limited number of schedule periods only and not a true optimisation considering all attributes such as waste destination location, design, cycle time and closure. This can be particularly applicable in large multi-pit bulk mining operations where one approach to meet Life of Asset ore tonnes and grade targets has been to maintain pit development flexibility resulting in large open pit areas and substantial expit Overburden Storage Area (OSA). The value opportunity is to develop a Life of Asset waste schedule source-to-destination optimisation prior to mine development considering all applicable attributes and routinely review throughout the Life of Asset taking account of improved ore and waste knowledge.CITATION:Taylor, N, Wright, R and Bettison, M, 2018. Utilising mine planning to deliver closure landforms through productive movement, in Proceedings Life-of-Mine 2018, pp 96–99 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Clément F. Bernier

One of the chief sources of the world's supply of asbestos lies in a belt of ultrabasic rocks which runs northeastward through an area called the Eastern Townships, south of the St. Lawrence River in the Province of Québec. The productive portion of this belt extends from the town of Asbestos in the south, for a distance of some 9,5 km to beyond the village of East-Broughton. The first discovery of asbestos in this region was made in 1874. Only crude fibre was produced until 1888 when the first mill was erected near the town of Black Lake. Since the inception of the industry, almost 100 years ago, no less than 100 different compa¬nies have been formed and 46 different mines have been operated. There are presently 5 active companies in the area providing direct employment for 4100 workers, down from 6000 during the seventies.

Jan 1, 1984

By J. W. Eckerd, W. S. Sanner, P. L. Woolf, R. E. McKeever

The Bureau of Mines experimental blast furnace was operated successfully with anthracite metallurgical briquets . Tuyère pressures were higher and more erratic than for operations using coke , and furnace " hangs " occurred more frequently . Higher hot - blast temperatures were required to maintain the quality of the metal . By using higher hot blast temperatures , the fuel and production rates and slag volumes were comparable to those obtained for all - coke operation . The anthracite metallurgical briquets exhibited excellent mechanical strength and descended through the shaft of the furnace with little breakage or reduction in size .

Jan 1, 1964

By R. D. Dey, V. Castranova, J. M. Antonini, J. A. Blackford Jr.

Alveolar macrophages (AM) exposed to cytokines or bacterial lipopolysaccharide (LPS) produce the free radical nitric oxide (NO·) by an inducible nitric oxide synthase (iNOS). They also release reactive oxygen free radicals following exposure to silica dust. The purpose of the present study was to determine whether NO· is produced by rat AM and/or recruited leukocytes following the intratracheal (IT) instillation of silica. Male Sprague-Dawley rats (175 to 225 g) were IT instilled with either silica dust (10 mg/100 g body wt) or LPS (0.25 mg/100 g body wt). After 24 h, bronchoalveolar lavage cells (BALC) and lavaged lung tissue were assayed for iNOS mRNA. Cell counts of BALC and iNOS-dependent (Nw-nitro-Larginine methyl ester [L-NAME]-inhibitable) chemiluminescence generated by AM were also determined. Northern blot analysis demonstrated that the steady-state levels of BALC iNOS mRNA were significantly increased by 3-fold following IT silica and by 7-fold following IT LPS. Partially enriched fractions of either AM or leukocytes from silica-treated rats both exhibited significantly elevated iNOS mRNA in Northern analysis. iNOS-dependent chemiluminescence was significantly increased in AM by 36-fold following IT silica and by 89-fold following IT LPS. Differential counts of BALC showed that AM numbers did not change in any of the treatments; however, red blood cells increased by 30-fold following IT silica and by 23-fold following IT LPS. Total leukocytes (polymorphonuclear leukocytes plus lymphocytes) increased by 58-fold following IT silica and by 274-fold following IT LPS. The results demonstrate that AM and neutrophils iNOS steady-state mRNA levels, AM iNOS-dependent chemiluminescence, and lavagable red blood cells and leukocytes all increased following IT silica. These findings suggest that NO· production in rat AM and neutrophils is increased in response to silica. NO· has the ability to then combine with superoxide and form a highly reactive toxic species, peroxynitrite, which may be responsible in part for silica-induced lung damage.

Dec 1, 1995

By R. L. Schmidt

The Methane Control and the Respirable Dust Groups at the Twin Cities Mining Research Center (TCMRC) cooperated recently in obtaining production samples of approximately 1 ton each, from the loading conveyors of a ripper, a borer, and a loading machine in conventional development headings. These samples were sized, in four stages, from plus 4 in to minus 10 µm. The conventional product had the least fines of the three production methods. The borer product had more fines than did the ripper product, but it also had a greater amount of large pieces. All three products, as sampled, had essentially the same amount of minus 10-µm particles. Photomicrographs and surface?-area comparisons were made. Gas -adsorption, surface-area determinations on particles under 37 µm give essentially the same value. Surface-area calculations, assuming spherical particles and no porosity, give a smaller area to the conventional product.

Jan 1, 1972

By William E. Robinson

Our earthly treasures are being quickly depleted. We have experienced what can happen in an energy crisis. You have read and heard all kinds of stories as to what caused this crisis. On the surface it would seem that all of a sudden a situation becomes a crisis whether it be fuel, potatoes, beef or whatever. Well, of course, they don't just happen. There is always a little fore-warning here, an indicator there. Someone recognizes a sign of potential trouble but is ridiculed when he forecasts it. We are running out of sand: Producers of aggregates who can say today ... "That couldn't happen to me", can well be awakened tomorrow to the cold fact of reality. It could come from any number of directions. Depletion is mostly foreseeable but zoning isn't. Legislation can also be sudden death to availibility. With the ever growing population moving into the rural countryside, available deposits are being sold either to developers or being zoned for restricted use. The fact that a gravel pit or quarry is located on a particular plot has not fazed some of the local planning boards when they decided to place the adjoining property in a residential Zone A. Proponents of zoning preach that such use is necessary to insure that the land will be put to its best use. Planning boards establish the best places for schools, homes, shopping areas, factories, etc., so that the individuals or groups are in harmony with each other. This is usually done to date without thought or consideration to the geological importance or potential of the area. Today over half of the United States is living under some form of land use restriction. Little consideration has been given to what lies under the ground to be zoned. Fortunately, the states are slowly getting around to geological surveying. I feel that it is about time that state and federal authorities institute governmental restrictions to prohibit or control local zoning ordinances which would deplete or deny an area of its natural resources. While I could continue for the balance of my time just on this facet of our industry's problems, my point is: How sure are you of your next load of sand? I could be well laughed at by some of you for saying that there is an alarmingly rapid disappearance of "nearby" sand and gravel reserves in many areas of the country. A questionable statement, except to those producers where depletion has already taken place.

Jan 1, 1974

By George A. Bell

This paper reviewing the leaching practice of the New Cornelia mines of the Calumet & Arizona Mining Co. at Ajo, Ariz., is the first of a series being prepared by the Bureau of Mines on leaching methods and costs in the various mining districts. ACKNOWLEDGMENTS The author acknowledges the assistance of T. G. Chapman, consulting engineer, and E. D. Gardner, supervising engineer of the Southwest Experiment Station, Bureau of Mines, Tucson, Ariz.

Jan 1, 1930

By R. L. Levens

Researchers at the U. S. Bureau of Mines conducted investigations to evaluate the potential for ground water contamination by mine waste used as backfill. Samples of cemented waste backfill and water discharging from drillholes and seeps were collected to use in chemical analyses and laboratory tests to determine the physical and chemical factors that control release of heavy metals to ground water. Greater water retention by cemented backfill (as compared to uncemented sandfill) reduces the surface area exposed to oxidation, which in turn reduces the amount of acid produced. The acid is neutralized by the cement and minerals contained in the backfill. The grain-size distribution of tailings used for backfill affects the structural integrity of cemented backfill under attack by acidic water; breakdown of the backfill structure releases neutralizing materials faster. Backfilled stopes in rock with low hydraulic conductivities will constitute preferential flow paths after mine flooding; however, the rate of flow through backfill will be much slower than when the stope is partially saturated during mine operation. Considering all factors, acid generation and release of metal ions from cemented backfill should be less than in uncemented sandfill.

Jan 1, 2010

By Ralph H. Sweetser

IN the recent world-wide deflation of commodity prices the coal industry, including both anthracite and bituminous coal, had reached a level where the actual delivered market prices received by the operators were usually less than the cost of production. Many steel companies and public utilities, operating their own "captive" mines, could have bought coal during the past three years for less money than the true cost of coal produced at their own properties. Competition within the coal industry itself was cruel to the point of profitless operation, and the competition of other forms of fuel was bearing heavily on the coal producers. They were thus forced into methods of production and utilization that they had hitherto ignored; there had been almost complete absence of any appreciation (by the bituminous operators especially) of the necessity of real research work in finding better methods of preparing coal for specific uses, and in finding new and profitable uses for different kinds and grades of coal.

Jan 1, 1933

By Paul V. Mullins

Review and evaluation of all available data on the vapor pressure of car-bon dioxide at the ice point, including previously unpublished results obtained by the Bureau of Mines, are presented. Suggested corrections and adjustments to all the data yield an average value of 26,136.4 mm mercury. Indicated agreement is within plus 1 part in 8,000 to minus 1 part in 11,000. A novel pressure bomb in which a sample of pure carbon dioxide is placed and sealed by a diaphragm fluid separator and its use as a reference pressure standard for extended and repeated use in the calibration of deadweight gages is described.

Jan 1, 1966

By C. C. Popoff

The growth of the aluminum-smelting industry in the Pacific Northwest, resulting from national defense requirements, emphasized a need for local sources of alumina to supplement the alumina production shipped from the East. Because supplies of foreign bauxite were being interrupted and our domestic bauxite reserves were inadequate, it was necessary to expedite the investigation of other possible sources of alumina during World War II. A program of investigation of high-alumina clay deposits in the Northwest was carried out jointly by the Federal Geological Survey and the Federal Bureau of Mines. As part of this program the Cowlitz clay deposits near Castle Rock, Wash., were explored by the Bureau of Mines in 1942-43. These deposits are near railroads, tide-water, and Bonneville Power Administration lines and within 22 to 100 miles of 4 aluminum-reduction plants.

Jan 1, 1955

By Reza Rahimi, M. Nili Ahmadabadi

"Because of high cost and shortage of primary resources of Ni-base superalloys, revert alloys can be used as a part of charging materials for production of superalloys ingots. The current study is based on recycling of IN738LC, a Ni-base superalloy, using 30% and 50% reverted alloy and balanced amount of virgin raw materials. Therefore, it has been attempted to cast an alloy with references to standard chemical composition and mechanical properties. After charging and casting in vacuum melting furnaces, chemical composition verification and non-destructive tests (i.e. Penetration and Radiography Tests), quality of samples were evaluated at elevated temperature by stress-rupture test. Results acquired from chemical composition and mechanical test indicate that cast ingots using 30% and 50% reverted alloy is reliable and consistent with the quality control requirements.IntroductionIn recent years, there have been many fluctuations in cost and availability of raw materials which are extremely determining in Ni-base superalloys production. Accessibility to the high purity metals such as Cobalt, Molybdenum, Tantalum, Niobium and etc. have been problematical during the past decades. Therefore, shortages of critical raw materials beside the economical considerations motivated the alloy suppliers and investigators to study and find alternate sources such as reclamation and recycling of scraps [1].There are a lot of reasons for the necessity of recycling; perhaps the most justifiable one is that consumers themselves produce scraps. For example, the weight of a finished superalloy product could be less than one-third of the cast alloy weight and in the case of complicated machined parts; this portion may reach to one-tenth [2]. High values of constituents, reduction of energy consumption and environmental concerns have all strengthened the obligation of recycling in Ni-base superalloys.Because of the high degree of risk in usage of improper materials for production of turbine blades, a delicately controlled program for recycling is needed. Depending on the type of scraps, this program can define the recycling procedure, required instruments, allowable percentage of scrap for usage and finally confidence level of the process."

Jan 1, 2012

By M. S. Moats, A. Luyima, W. Cui

"Organic smoothing additives are used to produce dense, thick, high-quality cathodes in copper electrowinning. Glue had been used traditionally and is still used in operations that do not employ solvent extraction to produce the electrowinning electrolyte. With the advent of solvent extraction–electrowinning, guar started to be used and remained in use for many years as it does not affect the phase disengagement in solvent extraction. Recently, however, guar has been replaced by less-expensive saccharide- and polyacrylamide-based additives. This paper is the first of a series of four papers that examine saccharides and polyacrylamides as new additives for copper electrowinning. A review of previous research related to copper electrowinning additives is presented here, along with a selected review of additives in other copper electrodeposition systems.IntroductionThe recovery of copper from solution by electrowinning was first practiced in the early 1900s, but it was the combination of solvent extraction with electrowinning (SX-EW) in March 1968 at the Ranchers Bluebird Mine (Kordosky, 1992) that changed the landscape for the electrowinning process. Most copper electrowinning capacity is now associated with solvent extraction, though some copper is still won directly from leach solutions (Robinson et al., 2013). The ability to produce high-purity copper cathodes from SX-EW has taken the continued improvement of SX-EW technology over the past more than 40 years.One of the technologies that has seen improvement is that of the organic smoothing agents used during the electrodeposition of copper in the tankhouse. These organic additives are added to the acidic copper sulfate electrolyte during electrowinning to improve the smoothness, brightness and density of the copper cathodes. The organic additives that are presently in use are different from those used in 1999 (Jenkins et al., 1999). Over the past decade, many tankhouses have replaced the use of guar-based organic additives with those derived from other saccharides. Until now, there has been no comprehensive publication in the open literature on the behavior of these additives during copper electrowinning."

Jan 1, 2016

By E. Fidler

A recent headline in the Wall Street Journal declared, "trendy management schemes very often fail." Many of the management techniques addressed in the accompanying article are associated with quality management including reengineering, benchmarking, total quality management, and employee empowerment. The article made the point that executives, employees, and customers who are involved in such programs rate the effectiveness of these programs very low, and the programs often fail. Yet, we all know of companies that have made significant advances in their operations using these same quality management practices. Why do a few succeed while many fail? History has shown that the companies that successfully carry out quality management programs have two things in common: 1) Strong leadership committed to the success of the program. 2) A comprehensive plan for carrying out and maintaining the program. Stated another way -the reason many companies fail is the lack of committed leaders and inadequate planning. It is ironic that the title of the Wall Street Journal article is "The Best Laid Plans."

Jan 1, 1994

By R L. Verburg, R Johnstone

DeBeers Canada Mining Inc (DeBeers) recently submitted an Environmental Assessment (EA) for its proposed Snap Lake Diamond Mine located in Northwest Territories, Canada. As part of the EA process, a site water quality management plan must be developed. Plan development requires an integrated approach such that the key factors influencing water quality can be identified and managed to minimise potential impact. A system model was therefore developed to simulate the site-wide water quality conditions and mass loadings to the principal environmental receptor of concern, Snap Lake, during operations and post-closure. Requirements of the simulation included integrating hydrology, geochemistry, hydrogeology and site management practices in a dynamic way. A unique feature of the site was the need to accommodate a complex flow system that included a feedback loop between lake water and mine water. A system model was constructed using the GoldSim software package that integrated on-site water quality and flow measurements, as well as results from independent groundwater flow and geochemical modelling efforts. The GoldSim model simulated concurrently the movement of 39 solutes through the subsurface mine and surface facilities. Solute sources considered included four different waste rock and tailings types, explosives use in the mine, treatment plant discharge, and recycled process water for dust suppression. Separate solubility constraints were identified for different regions of the flow system (eg underground mine; treatment facility; surface water bodies). Kinetic test data were used to derive temperature-dependent rate constants for use in calculating mass inputs from surface sources such as waste rock piles. The model generated water quality estimates over time for a variety of management scenarios at several potential discharge locations. The integrated approach used by the model was effective in identifying the significance of key factors influencing overall water quality such as explosives use, mine water inflow rates, waste rock reaction rates, site/mine management options, and effectiveness of treatment. The model provides an example of an effective tool for comprehensive, integrated system evaluation and management.

Jan 1, 2003

By Qinghua Gu, BUQING XUE, XUEXIAN LI, JIANGSHAN SONG, Qian Wang

To solve the problem of time-consuming and low precision in updating the open-pit vehicle transportation network, a high precision road network model construction method for unmanned vehicles in open-pit mines is proposed. This method can be divided into two steps. In the first step, an improved deep learning image processing model named DeepLabv3 + C (DeepLabv3 + Concat) is presented. Then, the road information extracted by the DeepLabv3 + C network is used to construct a three-dimensional model of the open-pit mine road network. In the second step, aiming at the time-consuming problem of unmanned vehicle meeting in open-pit mines, a vehicle meeting strategy was proposed. This strategy is used to guide the navigation of unmanned vehicles in open-pit mines. Besides, the DeepLabv3 + C network is verified by comparing the mIOU (means Intersection Over Union), accuracy, and continuity of road image extraction with the mainstream networks. The road network model constructed in the first step is quantitatively analyzed, and its performance is compared with GPS trajectory clustering methods. At the end of the paper, vehicle running simulation is carried out on the road network model by using Unity (a 3D visualization simulation software). The results show that the road network model constructed by this method can meet the navigation requirements of unmanned vehicles in open-pit mines, and the feasibility of the vehicle meeting strategy is proved.

Jan 11, 2022

By John V. Beall

GOING west from Denver on Route 6, the direct road to Grand Junction, one gets the first glimpse of mining a few miles east of Denver near Idaho Springs where the workings of defunct gold mines are visible on the sides of mountains along the highway. One enterprising company is turning a profit by showing tourists through the mine and mill and then selling them gold samples on the way out. We have always known that mining people are ingenious, but this proves it. About five and a half hours fast driving west from Denver brings one to Rifle, Colo., which is the site of the oil shale mine, retorting plant, and refinery of the U. S. Bureau of Mines. As you drive up to the mine, you can see a portal high on the face of the cliff in front of you where the mine surface plant literally hangs by its toenails. Below, the retorting plant and refinery gleam in the sunlight. Up at the mine, Fred Wright will show you how the oil shale is extracted in two benches (a third bench would be used for commercial mining) by the room-and-pillar method. In mining the top level, an underground crew of thirteen men have been able to produce 1500 tons of shale in each eight-hour shift. To do this, the mine is thoroughly mechanized. The mining method is de- scribed in the September issue of Mining Engineering.

Jan 1, 1949