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By P. R. Warner

This paper reviews the development of certain aspects of the electrical specifications of Anglo American?s suite of specifications for gearless mill drives (?GMDs?). These specifications are based on experiences in both Anglo American?s and others? operations, benchmarking against large hydro generators, the advice of industry and university experts, and continuous close co-operation with OEMs. To achieve a step change in availability additional final testing and electrical protection have been implemented, insulation requirements have been specified for machines to be operated at high altitude and clean area and access control systems have been developed.

Jan 1, 2012

By Robert C. Bates

Published information discussing uranium mine radon daughter controls and related costs was examined and used to develop an estimated (projected) cost per ton for any level of control. Results show a clear power function increase of cost for conventional dilution ventilation as the annual exposure limit is lowered. Projections can be made using any assumed changes in consumer price index (CPI) and radon daughter working level months exposure limit. Bounds on the estimated costs are provided, and applicability of the final equation is discussed.

Jan 1, 1983

By Frank L. Wideman

This information circular describes methods used in mining inclined beds of phosphate rock in mines operated by San Francisco Chemical Co. in Rich County, Utah. The mines are on the western flank of the Crawford Mountains, a short, narrow range in northern Utah near the Idaho-Wyoming corner (fig. 1). The western front of the range is a conspicuous wall of folded and faulted sedimentary rocks that rises abruptly 300 to 600 feet above the floor of the adjacent Bear River Valley. Rex Peak, highest point in the range, is approximately 8,000 feet above sea level. The area surrounding the mines is sparsely populated. Randolph, the county seat of Rich County, has a population of 650. It is 10 miles southwest of the mines by road and the only town in their vicinity.

Jan 1, 1958

By M. R. Geer

American and European practices in cleaning fine coal are strikingly different. The tables, launders, classifiers, and pneumatic devices used in America are seldom employed in Continental Europe, where much of the fine coal is cleaned in feldspar jigs, often supplemented by froth flotation of the extreme fines. This difference in choice of cleaning equipment may be fortuitous, but in large measure can be attributed to a difference in economic factors. Coal being more costly in Europe, there is greater emphasis on efficient cleaning of all sizes, including the extreme fines, and it is common to produce a high-ash middling for "on-site" consumption to avoid any waste of fuel value. The feldspar jig has been found advantageous under these conditions. In the United States fuel coal must be prepared as cheaply as possible, and metallurgical coal must be prepared as efficiently as possible; thus in both branches of preparation practice, any cleaning device that promises greater economy or higher efficiency warrants consideration. The feldspar jig, as employed in Europe, has a much higher unit capacity than the wet table used so extensively here and therefore offers economy in the capital costs of a washery through saving in space. As pointed out by Vissac,4/ the jig operates under automatic control, and therefore can cope with fluctuations in quality of feed. Maintenance costs for a single, large-capacity unit, such as the feldspar jig, would be expected to be lower than those for a battery of low-capacity cleaners. These considerations led the Bureau of Mines to undertake an investigation of the feldspar jig to determine its possible usefulness in this country.

Jan 1, 1958

By Jinxing Ji

Several fundamental aspects related to the nickel electrowinning from chloride electrolytes have been addressed in this paper. The thermodynamic study includes the activity coefficient of the hydrogen ion and the speciation diagram of NiCI2 solutions. The activity coefficient of the hydrogen ion (YH+) was calculated and estimated experimentally using a combination glass pH electrode. It was found that YH+ was greater than one in concentrated NiCl2 solutions and increased significantly with increasing NiCl2 concentration. The speciation diagram for NiCl2 solutions was plotted with YH+ and the effect of the ionic strength on the equilibrium constants being taken into account. It was discovered that the predominant nickel species in the acidic region were Ni2+ and NiCI+ in 0.937 M NiCl2 solution at 25°C. Electrodeposition tests demonstrated that higher Nit' concentration in the electrolyte improved the current efficiency of nickel electrodeposition (CENi). The additions of H3BO3, and NH4Cl increased very little the current efficiency of nickel electrodeposition at pH 1.5 and temperature 60°C. However, the addition of sulfate decreased the current efficiency of nickel electrodeposition. Nickel electrodeposition was also found to be a steady-state process since the amount of acid added to the electrolyte at a constant pH increased linearly with time during galvanostatic electrodeposition. The cathode surface pH during nickel electrodeposition was measured using a flat-bottom combination glass pH electrode and a 500-mesh gold gauze as cathode. The cathode surface pH was found always to be higher than the pH in the bulk electrolyte, and if the current density was sufficiently large, it would eventually reach a level causing precipitation of insoluble Ni(OH)2(s) on the cathode surface. Rotating disc electrode studies revealed that the rate of nickel electrodeposition was first order with respect to the activity of nickel ion and zero order with respect to the activities of chloride and hydrogen ions. The rate of hydrogen evolution was found to be first order with respect to the activity of hydrogen ion and to be zero order with respect to the activities of nickel and chloride ions. These findings indicate that nickel deposition and hydrogen evolution proceed independently.

Jan 1, 1995

By Batric Pesic

Calcium silicate slag (Di-Cal) and magnesium oxide condensate (MgO) are the by-products of magnesium smelting operations, As these oxides have acid neutralizing and metal precipitating properties, it was decided to examine their reactions with (a) individual heavy metals and (b) with a mixture of metals in solution, The resulting solid reaction products were further tested with respect to the stability of the contained metals, The stability of the solid precipitates were examined as a function of the method of precipitation and as function of the solution pH With respect to the method of precipitation, the performance of Di-Cal and MgO was compared to the performance of lime, an industry standard for heavy metal precipitation, Four different pH solutions (4,0, 5,0, 7,0 and 1 LO) were used to study the effect of pH on the stability of the precipitates. It was found that Di-Cal, in most cases, produced the most stable precipitates and thus, outperformed lime, Metal precipitates prepared by the addition of MgO were the most soluble for each metal studied, except for Se,

Jan 1, 2001

By M Schmid

German hard coal mining operations have decreased for more than 40 years. Current political decisions are leading to a discontinuation of subsidised black coal mining by the year 2018. This decision will, however, be reviewed once again in the year 2012. The enormous increases in productivity, which were achieved in previous years, have so far not led to an achievement of market requirements. Coal mining at depth of more than 1200 m in multiple seam environments is not yet competitive in global comparison. In 2008 the 24 faces left in eight mines produced about 20 million tonnes of usable steam coal. Management and the workforce will be reduced in parallel; from today until 2012 by more than half. The average age of personnel is increasing dramatically and nearly no new personnel are recruited. With this background in mind, increasing continuously coal mining productivity becomes more and more difficult. Above all, this goal was reached by mechanisation, then by increasing the mining machine power and then by enhanced machine control systems. The first attempts to automatically operate full face equipment from above ground were in the early 1980s. After successful automation of the face equipment, the emphasis is now on mine logistics. Autonomous monorail transport was introduced and tested in 2007. Since the development rate of machine improvements has its limits, the focus is on the full interaction of the total production system. Here information technology (IT) becomes important; the driver for more productivity. Actual developments aim for the complete and general homogeneous IT infrastructure both above ground as well as underground. The explosive environment needs high level investments in safe technology, eg access points for WLAN and fibre optics for underground use (ATEX certification). New technology availability also drives the enhancements of management and process control systems. Innovations in the mining industry often comprise technology advances through the adoption of well-known technologies. With virtual reality (VR) teaching and training systems advanced computational instruments, both in software and hardware development, were applied in the German coal mining industry for ten years. Widening lists of applications as well as the encouraging achievements show the economical benefits of investing in virtual reality technology both for teaching and training and for knowledge management. The paper discusses the actual technical achievements as well as in IT infrastructure utilisation and also in employment of virtual reality based systems. Special focus and deeper insight will be given to the fibre optics and WLAN hardware integration as well as software developments. The pocket personal computer (PC) is used to enhance underground material transport and data acquisition. The knowledge-based maintenance system (KBMS) integrates real-time virtual reality knowledge elements, such as repair process descriptions. It gives access to expert documentation by intelligent search algorithms and 3D representations of major mining machinery.

Jan 1, 2008

By A. M. Evans

Because of an urgent national need for manganese, the deposits in the Little Florida Mountains of Lune County N. Mex., were visited by O.H. Metzger, an engineer of the Bureau of Mines, on June 12 and 13, 1940, accompanied on the second day by S. G. Lasky, a geologist of the Federal Geological Survey. After this preliminary examination, it was recommended that exploratory work be done by the Bureau of Mines on several properties in the district. An exploratory project of trenching, sampling, and core drilling was started by the Bureau of Mines in September 1940 and completed in May 1941.2/ Work was done on three properties - the Luna mine, the American group of claims, and the Manganese Valley mine. The Little Florida manganese district is situated on the eastern slope of the Little Florida Mountains about 2 miles south of U. S. Highway 80-90, 12 to 14 miles southeast of Deming, Luna County, N. Mex. The principal claims comprise the Luna Manganese, American, and Manganese Valley groups.

Jan 1, 1949

By Fernando Jorge Dick

Artificial sulphides have been produced on the surfaces of heavy metal-oxide, minerals at elevated temperatures (1) and these sulphides gave consistently similar flotation characteristics as the respective natural sulphides. In the case of tin, the only natural tin sulphide known is herzembergite (SnS) which is found only in minor quantities, and its flotation behavior is not known. Balberyszki, Dorenfeld, and Carmi reported (2) tests with artificial tin oxide and pure cassiterite treated with hydrogen sulphide at temperatures above 750oc. They confirmed that the product could be floated in acid pulps. However, iron sulphides derived from pyrite, limonite, and hematite which are generally the major impurities in tin bearing ores could not be separated from tin sulphides under the conditions used by previous investigators. As a practical matter, if complex tin ores or complex low grade tin concentrates are to be treated by this process, it is necessary to be able to separate sulphidized cassiterite from other sulphidized minerals in the feed. The major metallic minerals, by weight, in complex tin ores are the iron minerals--pyrite, hematite, limonite, magnetite and pyrrhotite. These minerals become (or remain) sulphidized during the sulphidization process.

Jan 1, 1978

By R. M. Sweetin

Detailed descriptions by operating area of the Kidd copper smelter are presented, together with accounts of complement staffing, training, and preparation activities for smelter start-up in June 1981. Concentrate tonnages smelted in the first twelve months of operation were constrained by the capacity of the furnace off-gas system. However, modifications designed and introduced over that period, plus sustained efforts by operations and maintenance personnel have resulted in stepwise improvements in smelter performance.. Consistent operation at design feed rates has been well demonstrated over the third and fourth smelter campaigns and efforts continue on further improving the continuous smelter on-line times and increasing campaign life. In November 1982., following a seventeen month preproduction period, the Kidd smelter attained full operating status.

Jan 1, 1983

By O. W. Shimer, D. C. Helms, C. E. Brown

The early history and progress of anthracite stripping, from the first known operation at Summit Hill in 1821 through 1917, was covered in 1917 in a paper by J. B. Warriner,1 then chief engineer, now president of the Lehigh Navigation Coal Co., and stripping methods between 1917 and 1931 were the subject of a paper in 1931 by H. H. Otto,2 of the Hudson Coal Company. The present paper is confined to methods used today on pitching beds in the western middle and southern anthracite fields. The anthracite industry, not unlike other large industries, had been affected for more than a decade by the adverse economic conditions of the country. High development and operating costs and the competition of other fuels caused some collieries to be closed temporarily, while others were permanently abandoned. In order to obtain a larger tonnage at a lower development cost, a larger stripping program was put into effect by many companies. In 1932, stripping operations accounted for 3½ million tons, or 7 per cent of the total anthracite production of the year, and in the next 10 years this increased until more than double that amount, or over 14 per cent of the total production, was from stripping operations. These figures represent the total production of the entire anthracite region; unfortunately, the figures have not been separated from the different fields. There are some operations in the southern and middle western fields where the tonnage obtained from stripping amounts to more than 30 per cent of the total colliery production. Stripping operations on pitching beds present difficult problems. Owing to the various geological formations, a different situation is encountered in nearly every stripping pit; and because of the proximity of an overlying bed, it is very often necessary to load the entire overburden into trucks and haul it out of the pit to the dump area, although back filling and casting is done whenever possible. Beds in the areas described in this paper pitch from 20" to 90° and some are on the invert in many sharp folds and faults. Planning The more successful strippings have had adequate engineering analysis. Some work is being done without much preliminary planning, but many strippings would have failed completely if close supervision by the engineering department had not been maintained. Locations of stripping areas are determined as follows: I. By constructing cross sections over the areas and drilling sufficient diamond-drill or well drill holes to study the strata and to determine the location, thickness and pitch of the beds.

Jan 1, 1946

By O. W. Shimer, D. C. Helms, C. E. Brown

The early history and progress of anthracite stripping, from the first known operation at Summit Hill in 1821 through 1917, was covered in 1917 in a paper by J. B. Warriner,1 then chief engineer, now president of the Lehigh Navigation Coal Co., and stripping methods between 1917 and 1931 were the subject of a paper in 1931 by H. H. Otto,2 of the Hudson Coal Company. . The present paper is confined to methods used today on pitching beds in the western middle and southern anthracite fields. The anthracite industry, not unlike other large industries, had been affected for more than a decade by the adverse economic conditions of the country. High development and operating costs and the competition of other fuels caused some collieries to be closed temporarily, while others were permanently abandoned. In order to obtain a larger tonnage at a lower development cost, a larger stripping program was put into effect by many companies. In 1932, stripping operations accounted for 3½ million tons, or 7 per cent of the total anthracite production of the year, and in the next 10 years this increased until more than double that amount, or over 14 per cent of the total production, was from stripping operations. These figures represent the total production of the entire anthracite region; unfortunately, the figures have not been separated from the different fields. There are some operations in the southern and middle western fields where the tonnage obtained from stripping amounts to more than 30 per cent of the total colliery production. Stripping operations on pitching beds present difficult problems. Owing to the various geological formations, a different situation is encountered in nearly every stripping pit; and because of the proximity of an overlying bed, it is very often necessary to load the entire overburden into trucks and haul it out of the pit to the dump area, although back filling and casting is done whenever possible. Beds in the areas described in this paper pitch from 20" to 90 and some are on the invert in many sharp folds and faults. Planning The more successful strippings have had adequate engineering analysis. Some work is being done without much preliminary planning, but many strippings would have failed completely if close supervision by the engineering department had not been . maintained. Locations of stripping areas are determined as follows: I. By constructing cross sections over the areas and drilling sufficient diamond-drill or well drill holes to study the strata and to determine the location, thickness

Jan 1, 1944

By Robert Bottge

When a company develops a mineral property in a remote area of Alaska, it must consider how best to house its personnel. This Bureau of Mines report examines the economics of two options: company towns and company camps. The price required to maintain a 15% discounted-cash-flow rate of return (DCFROR) was derived for hypothetical 1,000-st/d cut-and-fill mines and 50,000-st/d open-pit mines located in three different regions of the State, One set of hypothetical mines utilizes a townsite; the other utilizes a relatively new concept, a fly-in camp or commuting operation, in which two shifts of employees operate the mine and all associated facilities for 1 week before being replaced by a second crew. The study shows that operating costs were higher for mines employing the commuting option than for mines having a company town because of the additional wages paid for overtime hours; however, the price required to obtain a 15% DCFROR for the single-product copper concentrate, f.0.b. the mill site, was significantly lower owing to the lower investment costs for the camp-type operation. The economic advantage for those mines utilizing the camp increases from south to north and from the coast toward the interior.

Jan 1, 1986

By J. E. Harris

The metallic elements, beryllium, calcium, cerium, lithium, manganese, titanium, vanadium and zirconium are used in metallurgical practice in relatively small percentages for the purpose of improving the physical properties of various alloys. No important uses for any of these elements have thus far been developed either in the pure form or in alloys of which they constitute the major constituent.

Jan 1, 1935

By E. G. Davis, H. P. LeVan, L. S. Smith

Leaching of a Georgia umber ore when using both ferrous sulfate and pickle liquor was studied in the laboratory . The ferrous sulfate content of the leach solution was the major factor affecting the extraction of manganese from the ore . Time , temperature , and the sulfuric acid content of the leach solutions had relatively little effect on leaching of manganese from the ore ; however , these factors did affect the amount of iron extracted from the umber and/or precipitated from solution . Simulated countercurrent leaching of the ore with pickle liquor containing 130 gpl (grams per liter ) ferrous sulfate ( 48 gpl ferrous iron ) produced a pregnant solution having 16 gpl manganese and 41 gpl iron . Filtration tests of the leach slurries indicated that separating the leach solution and solids by vacuum filtration was impractical , whereas pressure filtration was feasible when the cake thickness was limited to about three- fourths of an inch . Fired pellets of the filter cake yielded a firm , hard product analyzing 56 percent iron and less than 0.1 percent sulfur .

Jan 1, 1964

By L Q. Amorim

The mining district of the Quadrilátero Ferrífero (QF) in southeastern Brazil contributes to 70 per cent of the Brazilian iron ore production, which reached 370 Mt in 2010. Traditionally, four iron ore types were mined in the QF region:1. soft haematite,2. hard haematite,3. friable ‘itabirite’ (the Brazilian name for metamorphosed banded iron formation), and4. canga (an indurated iron-rich crust).With the exception of the hard haematite, these categories derive from supergene enrichment of the Paleoproterozoic Cauê Itabirite. High current iron ore demand means that the QF high grade supergene ores will be depleted in a few decades. Consequently, several mining projects are being developed to exploit unenriched, fresh itabirite. Among them, the Mineração Usiminas Serra Azul project in northwestern QF is one of the most advanced. Four major itabirite types occur in the QF region:1. siliceous (or standard),2. dolomitic,3. amphibolitic, and4. magnetitic.The dominant type in Serra Azul region is a fresh siliceous itabirite, composed essentially of haematite, martite and quartz that averages 36 per cent Fe (51.5 per cent Fe2O3) and 47 per cent SiO2. The second type, the magnetitic itabirite, consisting of magnetite, martite, gruneritecummingtonite, quartz, dolomite, stilpnomelane, and subordinate haematite, is typically a strongly magnetic greenish banded iron formation with the iron grade varying between 25 and 35 per cent. Chemically, it differs from the siliceous itabirite due to the relatively high CaO, MgO and, consequently, high LOI contents. Together with supergene ores, fresh itabirites have been included in the ore reserves of the Serra Azul project. We anticipate that all the four types of fresh itabirite will be incorporated as ore in the QF region, causing a huge increase on the iron ore resources of the district, and representing enormous environmental and technological challenges for the local iron ore industry.

Jul 11, 2011

By F. Calizaya

The Western Mining Training and Translation Center is a consortium of four universities devoted to developing educational and training projects to reduce the incidence/accident rates in the mining industry. The center consists of Missouri University of Science and Technology, Montana Tech, the Colorado School of Mines and the University of Utah. It is fully funded by the National Institute for Occupational Safety and Health (NIOSH). The center manages 15 educational projects and one translation project. Hazard Identification and Risk Assessment (HIRA) for Small Mines is an educational project managed by the University of Utah. The objectives of this project are to identify critical mine hazards, assess risks; outline procedures to reduce accident/incident rates in small mines in the western United States and to train mine workers and super-visors on HIRA in each participating mine. To accomplish these objectives, the HIRA personnel visited 15 small mines in Utah, Colorado, Nevada and California. At these mines, most operators were employing independent contractors to perform several tasks ranging from drilling, blasting and mucking of rock at the work site to hauling ore to a processing plant. The operation of diesel-powered equipment was one of the major tasks performed by the contractors. This article presents three case studies in which contract workers performed a number of tasks with no reportable incidents but did so unsafely. It also highlights the training received by most contractors, the constraints imposed upon them and the safety hazards to which they are exposed most frequently.

Jan 1, 2008

By S. Garcia, J. Gebhardt, D. McBride, A. Hernandez, A. Esplín, M. Cross

The Minera Yanacocha operation consists of several heaps interconnected with ponds and gold recovery plants and presents various operating challenges. A comprehensive process model has been developed in order to better understand the effects of certain operating parameters and inventory issues. An integral component of the process water/mass balance is a model of each heap that describes heap behavior based on the individual characteristics of the heap. The heap models are linked to a mass balancing program in order to track flows and concentrations throughout the circuit. A case study of the process heap model is presented for the La Quinua heap, including results for the normal base line operation and several operational problems such as loss of solution flow to the heap (i.e., pump failure), increased flow to a section of the heap (i.e., pond volume control), effect of significant rain events, and impact of a change in material properties (i.e., change in ore type). The impact on heap operating efficiency is discussed with regard to effects on recovery and gold solution grades.

Jan 1, 2007

By W. P. Yant, G. W. Jones

"Introduction.During the past two years the Bureau of Mines has conducted a study of natural-gas heaters*** to determine (1) what types of heaters literate carbon monoxide; (2) why carton monocide is liberated; and (3) how, by change of design or construction, the liberation of this gas can be largely eliminated, In addition to the above study the bureau has investigated cases in the Pittsburgh dis¬trict where fatalities have resulted from carbon monoxide given off by natural-gas heaters.Since these fatalities were first brought to the attention of this bureau through the press, it is likely that some cases were missed and thus not listed. On the other hand, some cases reported as being due to carbon monoxide poisoning, on investigation were found to be due to causes other than carbon monoride.The cases listed herein were shown in all probability to be due to carbon monoxide. Those in which there is any doubt have been omitted; so have those in which there was part asphyxiation, where the victims later recovered."

Feb 1, 1924

By D. H. Horswill

The paper point out considerating how mining activities contributed to sustainability, it is important to consider how exploitation of a finite resource can be regarded as sustainable. The now well–recognized concept of sustainable development holds that society’s pursuit of development that meets current needs should not compromise the ability of future generations to meet their own needs. Sustainability, then, contemplates multigenerational enjoyment of a quality of life that includes social and economic benefits and a healthy environment in which to live. In this sense, the benefits of our activities must always exceed the risks. Many other companies are also making significant inroads along the path to sustainability.

Sep 13, 2001