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By K. K. Dehn

This study focused on determining the stability of thin shotcrete fill fences at a hard rock mine in northwestern Ontario during increased pour rates of paste backfill. Determination of the stability of the fence is needed for both personnel safety and to avoid failure of a fence. Failure of a fill fence during backfill activities would have severe impacts on production and potential hazards to nearby workers. Approved fill fences at the mine are a slender design of 10.5 centimeters of shotcrete applied to a rebar framework with burlap lined ?bedspring? backing. Approved mine standards dictate that fill rates may not exceed 1.5 meters of paste depth per 10-hour shift when pouring behind a flat fill fence. To decrease the backfill cycle time the study looked at fence stability during increased pour rates of 2.5 meters paste depth poured within a 10-hour shift. An instrumentation design was developed including pressure cells, strain gauges, and tilt-meters that were built into experimental fences to observe the effects of increased pour rates on lateral wall pressures, strain development in the rebar and shotcrete reinforcement, and physical deformation patterns along the face of the fence. The data was analyzed for overall stability.

May 1, 2007

By A. Mcdonald, F. W. Breaks, T. F. Morris, S. A. Averill, D. C. Crabtree

Abstract-Gahnite, a zinc-bearing spinel, is a resistate mineral that may be used as an indicator mineral of polymetallic deposits in high-grade metamorphic terrain. The Ontario Geological Survey recently completed surficial mapping and sampling programs in the Separation Lake area of northwestern Ontario and Kinniwabi Lake area of northeastern Ontario in which gahnite was recovered from samples of surficial sediments. Ternary plots of the composition (ZnO, MgO, FeO[t]) of gahnite recovered from these surficial studies reveal three distinct groups: Group 1 is characterized by low (< 1 wt%) MgO values; Group 2 by higher (>1 wt%) MgO values; and Group 3 by higher FeO(t) values than Groups 1 and 2. The composition of in situ gahnite recovered from volcanogenic massive sulfide mineralization, Zn-rich Sedex-type mineralization and peraluminous rare-element mineralized granite and pegmatite also was determined. The composition of the gahnite obtained from surficial samples was compared with that of in situ material. Gahnite from the peraluminous rareelement granite and pegmatite overlapped very well with surficial gahnite of Group 1. Gahnite from volcanogenic massive sulfide mineralization and Sedex-type mineralization overlapped well with surficial gahnite of Group 2. These results suggest that determination of gahnite composition in indicator mineral surveys may be useful in exploration programs when assessing the mineral potential of a region.

Jan 1, 1997

By C. G. Maier

The present trend of chemicometallurgical research toward widespread and inclusive use of thermodynamic methods requires the inclusion of available data of this sort in any comprehensive metallurgical report . Such data for manganese are far from adequate for the full utilization of these methods . Even if our knowledge of these properties is weak , the collection of available figures is nevertheless well worth while , especially if their utilization in an approximate way may show inherent possibilities of application . No less important is the necessity for discovering the vital gaps in the existing information , to serve as a basis for further pertinent study . The utility of the thermodynamic methods of Lewis and Randall ( 234 ) 3 has become increasingly evident to metallurgists . It is true that at present no better approach to the general , fundamental problems of chemical metallurgy is available than close adherence to these methods . The effort is here made to collect and correlate , as far as possible , significant quantitative thermodynamic data on manganese and its metallurgically important compounds . There are considered here only the intrinsic properties of pure materials . The order maintained as far as possible will be as follows :

May 1, 1934

By Ernest F. Burchard, J. R. Thoenen

"INTRODUCTION Technically speaking, bauxite is not a definite mineral but a mixture of several minerals belonging to a group of partly consolidated material known as laterite, which have been formed by surface weathering of rocks.The term bauxite is applied to the ore of aluminum, although a substantial amount is used for other purposes, such as a base in certain chemical industries and in the manufacture of artificial abrasives, refractories, and certain cements. Although bauxite has not been classed as strategic it now appears that the domestic supply may be insufficient for expanded defense requirements.Until recently, domestic production of metallic aluminum has been ample to meet requirements, but estimates of pyramiding future needs of the defense program have caused serious attention to be directed to the self-sufficiency of this country, both as to the supply of the raw material, bauxite, and the metallurgical capacity available to convert the ore to metallic aluminum.At the request of the Secretary of the interior, representatives of the Bureau of Mines and the Geological Survey recently investigated domestic resources of bauxite.A preliminary study of published literature and a field investigation disclosed that"

Nov 1, 1941

By J. A. Murray

Maintaining satisfactory air quality in electrowinning tankhouses is problematic and costly, particularly as plant operating current densities have increased. Conventional approaches have not proved completely effective. These include the use of beads, hollow spheres, surfactants and coalescer devices. They require powerful ventilation systems to be installed. As workplace and environmental regulations become more stringent, containment of the acid mist at its source is more attractive. An electrode cap system based on this approach has been developed and tested in two commercial copper electrowinning tankhouses.

Jan 1, 1996

By AIME AIME

AS a new departure the annual business meeting was held at 4 p. m. on Tuesday, Feb. 16, instead of in the morning, as previously. The retiring President, Robert E. Tally, called the meeting to order and briefly spoke of the large measure of success that had been attained in balancing the budget of the Institute in 1931, so that, although receipts had declined over $26,000 compared to the previous year, expenditures had come within $3,000 of income. He referred in complimentary ,terms to the work of the committees on Membership, Admissions, Papers and Publications, and MINING AND METALLURGY, from which more would be heard late:. He also announced that a large and important committee on economics has been under consideration, and will be announced later. As an evidence of growth it was noted that a new Division, Mineral Industry Education, had been organized just an hour previously.

Jan 1, 1932

By A. Mcdonald, F. W. Breaks, T. F. Morris, S. A. Averill, D. C. Crabtree

Gahnite, a zinc-bearing spinel, is a resistate mineral that may be used as an indicator mineral of polymetallic deposits in high-grade metamorphic terrain. The Ontario Geological Survey recently completed sur?cial mapping and sampling programs in the Separation Lake area of north-western Ontario and Kinniwabi Lake area of northeastern Ontario in which gahnite was recovered from samples of sur?cial sediments. Ternary plots of the composition (ZnO, MgO, FeO[t]) of gahnite recovered from these sur?cial studies reveal three distinct groups: Group 1 is characterized by low (< 1 wt%) MgO values; Group 2 by higher (>1 wt%) MgO values; and Group 3 by higher FeO(t)values than Groups 1 and 2. The composition of in situ gahnite recovered from volcanogenic massive sul?de mineralization, Zn-rich Sedex-type mineralization and peraluminous rare-element mineralized granite and pegmatite also was determined. The composition of the gahnite obtained from sur?cial samples was compared with that of in situ material. Gahnite from the peraluminous rare-element granite and pegmatite overlapped very well with sur?cial gahnite of Group 1. Gahnite from volcanogenic massive sul?de mineralization and Sedex-type mineralization overlapped well with sur?cial gahnite of Group 2. These results suggest that determination of gahnite composition in indi-cator mineral surveys may be useful in exploration programs when assessing the mineral potential of a region.

Jan 1, 1997

By Wilbert J. Huff, Raymond H. Moore

"Black powder is employed widely in peace and war. Its properties are therefore of considerable interest to many. The Bureau of Mines frequently is asked to furnish information on its use and safe handling in the mining and mineral industries in times of peace and is now engaged in studies of its application to the arts of war.Black powder has been the agent in many accidents - some very disastrous - and its handling and use are deemed very hazardous. The belief is widespread that the hazards are due principally to the ease with which the powder is ignited by a hot spark or flame in contradistinction to high explosives; these usually are ignited only with difficulty, and some burn incompl0tely and to a certain extent are self-extinguishing. Primary precautions, .therefore, should be taken to prevent the access of heat, spark, and flame.In black powder manufacturing operations a frequent source of disaster is the initiation of fires and explosions in the wheel mills in which the sulfur, charcoal, and nitrate are incorporated. Long experience has indicated that the wheel mill probably will fire if the powder is not kept moist enough; manufacturing supervision calls for the maintenance of a minimum moisture content, at least during the milling. Accidents occur elsewhere in the manufacturing line, and in an endeavor to minimize these, particularly those happening in corning mills, one of the writers suggested many years ago that a suitable humidity be maintained in other operations in the hope that it would serve protectively as in the wheel mill. The experience of one company for many years with this practice was favorable. It seemed desirable therefore, to explore the question experimentally."

Nov 1, 1944

By Craig M. Jensen

A laboratory assessment of prompt and delayed neutron activation analysis with 252Cf and 14MeV neutron sources, for use as an in-situ method of determining low-level copper concentration has been performed. A simulated borehole using porphyry ore was constructed and varying copper concentrations were simulated using copper rods. Prompt neutron activation analysis experiments were consistant with earlier work and do not appear to be feasible fur copper concentration of 1.5% or less. Delayed neutron activation analysis experiments indicate that copper ore concentrations of less than 0.1% are detectable using either the 511-KeV gamma-ray of copper-64 or the 1039-KeV gamma-ray of copper-66, with high resolution detectors such as Ge (Li) or intrinsic germanium.

Jan 1, 1977

By P. D. Laverty

This report describes a processing method developed by the U.S. Bureau of Mines to produce high-quality flake graphite from the steelmaking waste known as kish. The kish produced by current steelmaking practices is a mixture of graphite, desulfurization slag, and iron that is skimmed from the molten iron feed to the basic oxygen furnace. It is estimated that the graphite content of kish discarded by U.S. steel plants is more than sufficient to meet the total U.S. demand for flake graphite. That need is now filled by natural graphite from foreign sources. Kish was treated by a combination of screening and hydraulic classification to produce a concentrate containing greater than 70 pct graphite. Leaching of the concentrate with hydrochloric acid solution gave a graphite product with 95-pct purity. An optional secondary leaching operation with hydrofluoric acid produced graphite with a purity of 98 pet or greater. The flake size of graphite from kish ranged from 10 mesh down. Evaluation of test samples by industrial graphite users indicated that kish graphite is a suitable substitute for the natural material for most uses. A process flowsheet and material balance for pilot plant design are presented.

Jan 1, 2010

By Kazunori Matsushita, Masaru Sakakibara, Kenji Harada, Naotoshi Shinkawa, Mitsuo Nozu

The Sand Compaction Pile (SCP) method has been widely used as a typical countermeasure against liquefaction in Japan, and its effectiveness has been confirmed in many case histories of damages caused by the past large-scale earthquakes. A series of studies were conducted to evaluate the effectiveness of the compaction method and other factors, if any, in sustaining a seismic force that is greater than the assumed one and caused no damage. Based on the results of these studies, the Architectural Institute of Japan (AIJ) has indicated in its “Recommendations for Design of Ground Improvement for Building Foundations” published in 2006 that the liquefaction resistance ratio (tl/sz) of the composite ground, which consists of sand piles and surrounding compacted ground, is higher than the RL calculated by using the SPT N-values of the ground in-between the sand piles. In this paper, statistical analysis of safety factor against liquefaction, FL, was performed by using the SPT N-values of ground in Port Island and Rokko Island which were both fully reclaimed islands in Kobe city during the 1995 Hyogo-ken Nambu Earthquake (classified as intense shaking) and, together with the consideration of relative settlement, resulted in tl/sz of the composite ground being 1.5~2.5 times of tl/sz of the soil in-between piles after improvement. Furthermore, the liquefaction resistance curve of SCP-improved sites obtained from the relationship between SPT N-values and cyclic shear stress ratio during the 2011 off the Pacific Coast of Tohoku Earthquake, which was regarded as long-duration earthquake, was plotted to the left side of the curve originally proposed by Japan Road Association. Thus, the liquefaction resistance of the improved ground was found to be higher than that of the natural ground, even for the same SPT N-values, verifying the validity of the AIJ recommendation.

Jan 1, 2017

By V. P. Yakushkin, B. S. Ksenofontov

"Multistage model designed and used for more detailed description of floatation process. The study develops a new model of flotation kinetics description. It defines flotation as process that consists of several stages: air bubbles and particles are separate, air bubbles and particles form a raising aggregate, aggregate raises to froth layer. This description significantly differs from commonly used model, which is much simplified. The multistage model gives an in-depth description and considers different aspects of flotation. Experimental approval of the new model resulted in its accuracy.The model is to be used for description of all flotation processes’ kinetics of wastewater treatment. It helps in accurate designing of flotation treatment plants and may be used for further research of flotation process. Columnar flotation installation was designed by using multistage model. This installation consists of new tubular aerators with special ejectors, froth pressing system as well as unit of thin-layering lighting to catch microflotocomplex “particle – bubble”. Usage of tubular aerators allowed to aerate the overall volume of pulp. Due to use of special ejectors with longer mixing camera we state higher volume of small-sized floto-active bubbles. Use of multistage model allowed to optimize and get higher technological results of potash salts enrichment. Tests were conducted on centrifuges-floatation installation system. Meanwhile, froth concentrate contained mainly thin hydrophobic particles sized circa 0,1 mm. As a result we set that during floatation cleaning process of froth concentrate 95-98% of chloride potassium (KCI) is derived from foam.The final product satisfies production quality. Columnar floatation installation productivity was 17 – 21 m3/m2h, which is a high technological result. Columnar floatation installation is one of the best examples of concentrating equipment using nearly all technological indices."

Jan 1, 2018

By M. R. Yenchek

The U.S. Bureau of Mines designed and constructed sensitive and coordination-free ground-fault relays (GFR&apos;s) for use on mine power systems. First, a list of GFR attributes for mine ac utilization applications was compiled. These practical guidelines specified design, construction, transient immunity, reliability, and operating criteria. The time-current characteristics of the ac and dc units, subsequently fabricated, were designed to be below the human electrocution threshold. The significant and highly variable capacitance of high-voltage distribution cables was found to preclude the sensing of ground currents in the milliampere range. However, the coordination-free system developed for high-voltage distribution should enhance safety by significantly decreasing response time to ground faults. Implementation of the sensitive GFR technology in the mining industry has the potential to eliminate the majority of injuries and nearly all the deaths resulting from contact with energized components.

Jan 1, 1990

By John Durkin

Electromagnetic narrow-band signals were transmitted through the earth at 27 coal mines located throughout the United States. From those Bureau of Mines tests, apparent earth conductivity values were derived based upon a homogeneous half-space model of the earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated, and the results indicate that the mine depth can be an adequate predictor of the apparent earth conductivity above coal mines. Apparent earth conductivity was found to decrease with mine depth.

Jan 1, 1984

By John Durkin

Electromagnetic narrow-band signals were transmitted through the earth at 27 coal mines located throughout the United States. From those Bureau of Mines tests, apparent earth conductivity values were derived based upon a homogeneous half-space model of the earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated, and the results indicate that the mine depth can be an adequate predictor of the apparent earth conductivity above coal mines. Apparent earth conductivity was found to decrease with mine depth.

Jan 1, 1984

The wealth of a nation may be measured in many ways, but one of the most important is its natural resources, particularly its minerals. Minerals create the wealth upon which economic prosperity and defense preparedness rest. Managing mineral resources for the benefit of all Americans continues to be an important national goal. In its 78-year history the U.S. Bureau of Mines has established itself as the world&apos;s premier mineral information and research agency. Its authoritative, comprehensive data and pioneering research have contributed significantly to a strong U. S. mineral position in the world.

Jan 1, 1988

By Hakan Uyguçgil, Beril Bayraktar, Adnan Konuk

Mining is one of the industries with the highest risk of occupational accidents in Turkey and globally. The most important feature that distinguishes the mining industry from other sectors is the constantly changing working conditions. The risk of accidents is very high, especially in underground mining, and can happen for several reasons. Therefore, it is essential to carry out all necessary measures in coordination with other disciplines to adapt to changing workplace conditions. The dangers that might occur underground must be determined in advance, controlled at their source, or eliminated since it is critical to take the necessary precautions before the accident. Accident prevention will protect miners’ living conditions by contributing to the country’s economy through reduced labour and production losses. In this research, the data from 13,653 accidents reported in the Karadon Hard Coal Enterprise between 2000 and 2011 were analysed and compared using the Life Table and the Kaplan-Meier methods. Accident records were classified and analysed into four categories: environmentalrelated accidents, equipment-related accidents, person-related accidents, and other accidents. Findings in terms of survival time indicate that environment-related and person-related accidents had the highest risk in Karadon, with equipment-related accidents having the lowest. This study established the reliability of using survival analysis methods to investigate occupational accidents in the mining sector. Given that environment-related and person-related accidents occur in a relatively short period, such as 1 year after starting work, it has been recommended that research be done to improve workplace and occupational safety measures and broaden the training given to miners. Additionally, it has been determined that increasing the use of automation and mechanisation in underground coal mines, combined with developing a thorough equipment safety training programme to raise awareness of the danger, can help prevent person-related occupational accidents caused by the interaction between equipment.

Aug 5, 2023

By Kenneth M. Maas

The Bureau of Mines inventoried the land in southwestern Alaska to classify ownership and availability and compared this land with known mineral terranes and mineral deposits. This report discusses and quantifies the potential for favorable location of mining claims for metalliferous (locatable) mineral deposits. Of the nearly 24 million acres that constitute the study area, approximately 3.6 million acres or 17% are available for mineral location, 3.4 million acres or 14% are available with restrictions, and 17 million acres or 71% are unavailable. Mineral terranes are known to underlie about 7.8 million acres or 33% of the study area; 3 million acres or 38% occur on land available for mineral location, 1.3 million acres or 17% occur on land available with restrictions, and 3.5 million acres or 45% occur on unavailable land. The State of Alaska has opened over 91 % of its land in the study area to mineral location; in comparison, the Federal Government allows mineral location on 0.07% of the land under its jurisdiction. There are 117 known mineral deposits or occurrences within the study area, including 77 lode deposits and 40 placer deposits. Of the 41 lode deposits occurring within a mineral terrane, 2 occur on available land.

Jan 1, 1988

Real economic growth for 1988 may fall short of the 3.3% projected by the U.S. Department of Commerce in August 1988 be-cause the summer drought and intense heat in many areas curtailed output more severely than expected. The economy grew at an average annual rate of 3.0% for the first three quarters of the year, slowing in the second and third quarters. Export growth, which occurred even as the dollar edged up com-pared with other industrial country currencies, was an important factor in the expansion. Notable gains were posted in sales of machinery, computers, aircraft, chemicals, and telecommunications equipment. Imports increased, but not as much as exports, and the U.S. trade position was still much improved from that of 1987. Personal consumption expenditures grew slightly faster than the economy as a whole. Purchases of consumer durables showed notable strength in the first half of 1988, but slowed down in the third quarter. [ ] Despite the moderate rise in interest rates, business spending for new plant and equipment also rose and contributed to 1988 gross national product (GNP) growth. Both new business investment and export demand spurred orders for U.S.-made machine tools. Orders for machine tools for the first 8 months of 1988 were almost triple those for the corresponding period in 1987.

Jan 1, 1988

By L. E. Young

IT has been said the British Empire was built on British Coal. In all the postwar planning for Great Britain the necessity for producing cheap coal and the prosperity of the coal industry are given first consideration. On Jan. 23, 1945, there was released in London a "Report to the Colliery Owners" which had been awaited with great interest. This was entitled "A Plan for Coal" and was the recommendation of Robert Foot, chairman of The Mining Association (Colliery Owners), prepared at their request. Presentation of the "Plan" at this time is particularly significant as it is an answer to the demand for nationalization of the coal industry by the Labour Party and at the same time is a carefully considered program for postwar reconstruction, prosperity, and stability. In the words of Mr. Foot, If the coal industry for the first ten years after this war is to find itself in a situation similar to the one it occupied for the ten years following the last war, with its record of disputes, strikes, stoppages, short-time working, unemployment, and, with it all, a completely insufficient margin of profit, and all the insecurity and instability in our basic industry that was brought with them, it is goodbye to any real prospect of full employment, social security, and high standard of living. To present an elaborate review of the conditions which have brought to a crisis the unfortunate situation in the British coal industry is here unnecessary, but certain of the salient points

Jan 1, 1945