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The object of this paper is to give a description of the new office and changehouse building and equipment at the Zinc Corporation Limited, the office section of which has now been in full use for approximately three years, and the changehouse section for approximately two years. As the expectations of the design have been fully realized, it is thought that this description will be of interest to members and possibly of some use to others faced with similar problems.GENERALIn the centralization of the surface plant around the new main shaft the combined office and changehouse building forms a prominent feature, being located between the shaft and the mill and facing the workshops on the northern side.The scheme for housing all employees in one building was proposed by the Manager, Mr. A. J. Keast, who was familiar with a similar successful structure built at the McIntyre Porcupine Mines Ltd. in Ontario, Canada.The principal features of this building were adopted as a basis for design, and the present layout evolved to suit the particular requirements of this mine.Some of the advantages of the design are:(a) Economy in first cost and space occupied when compared with plants having separate office and changehouse buildings.(b) Easier and more constant supervision of employees and of the plant by the senior staff members.(c) Close contact between officials of all departments.(d) Close covered connection between changehouse and shaft.(e) Avoidance of duplication of ,essential services such as electric power, water, heating plant, sewerage, etc.The Managing Director, Mr. W. S. Robinson, further instructed that the following requirements be adhered to in the new building:(a) Ample accommodation to be provided for office staff and other employees.(b) Special attention to be paid to lighting, both natural and artificial.(c) Working temperatures to be controlled to facilitate comfort and efficiency.(d) The buildings and equipment' to be of a permanent nature with furnishings and fittings of modern design.

Jan 1, 1941

By Paul Gemmill

Production was first recorded from the Pioche district in 1864, and it has continued to show an inherent ability to take on new life after periods of depression in the metal markets. Production from replacement leadsilver- zinc sulfide ore bodies in limestones of Cambrian age now accounts for several times the gross value of silver production from rich fissures in Lower Cambrian Quartzite. Aggregate production of some 6 million tons represents a gross value over $100-million. Future output is expected mostly to be from limestone replacement deposits of which the most productive are "channels" of ore up to several hundred feet wide and several thousand feet long with thicknesses from a few feet up to 50 feet. Such channels are restricted to the lowermost limestone bed of the district, about 250 feet above the basement quartzite. The "blotter-like" characteristic of this highly productive Jimesto~e bed in absorbing mineralization is believed to be, at least in part, due to lithology, including free carbon in the bed, which has created a unique set of conditions for delicately balanced mineralizing solutions that rejected any tendency to replace siliceous wall rock and were properly constituted for replacement of Limestone. All recognizable orogenic history is considered to be related to the Basin and Range faulting that created the mountain ranges. The faults developed after mid-Tertiary time and after widespread extrusives that are themselves involved in the faulting. Flat faults, formerly believed to be part of regional thrust faulting, are now interpreted as gravity slide faulting that can be shown to be large in magnitude and not simply local landslides. Large slide faults generally have concealed the great magnitude of mountain-bordering faults. Mineralization that accounts for ore is later than the faulting. Most faults are pre-mineral since they influence the shape of ore bodies, and some clearly have been offset by fault fissures containing ore. Post-mineral movement probably has been an important component of some large, initially pre-mineral faults. A single period of mineralization was begun by the introduction of large quantities of ironmanganese carbonate, and, in places, carbonate manganese with minor values in sulfides. Closely following the carbonate invasion, massive sulfides were brought in, usually replacing part of the carbonate body though in some places the massive sulfides replaced limestone that was not previously mineralized. Manganese mineralization is not a "halo" but leaks of manganese to higher formations and to the surface are the most significant exploration guides. The Pioche district is expected to be long lived with technological developments in ore treatment being important to the exploitation of low-grade manganiferous ores, while aggressive exploration is expected to find important quantities of bedded lead-silver-zinc ores of the massive sulfide type.

Jan 1, 1968

By Marcos Felipe Macêdo Cardoso

Com o aumento dos investimentos energéticos na região amazônica, surge a necessidade de recapacitação das linhas de transmissão existentes, a fim de mitigar as interrupções de fornecimento de energia para os grandes centros urbanos. Dentro deste contexto, as ligas termorresistentes possuem alta capacidade de transmissão de eletricidade, propondo-se avaliar a influência do tratamento térmico sobre as propriedades da liga Al-0,05%Cu-[0,35-0,45]%Fe modificada pelo teor de 0,15%Zr. Os lingotes foram obtidos por fundição direta em coquilha metálica, usinados e envelhecidos artificialmente por 04 (quatro) horas a 150ºC e comparado seus resultados para a mesma liga sem tratamento. A influência do tratamento térmico foi avaliada através da caracterização macroestrutural, elétrica (ensaio de resistividade) e mecânica (ensaio de tração). Foi selecionado o diâmetro que apresentou os melhores resultados nos ensaios, para realização dos testes de termorresistividade, segundo o Protocolo COPEL e a Norma ASTM B941-10. O tratamento térmico provocou ligeiro aumento nos valores de condutividade elétrica e limite de resistência à tração (LRT), sem alteração da macroestrutura. Como destaque, o diâmetro 3,0 mm apresentou os melhores resultados de LRT e condutividade, cujos fios foram caracterizados como termorresistentes com e sem tratamento térmico segundo o Protocolo Copel, e somente os fios com tratamento térmico segundo a norma ASTM B941-10.

Oct 30, 2017

By W. S. Sadik

This paper presents the ventilation design for an underground testing facility in a salt medium. The underground workings consist of two-12 ft. (3.66 m) diameter watertight shafts and approximately 6000 ft. (1830 m) plus of drifting. These facilities are designed for the purpose of providing access for an in-situ testing of a salt horizon in which a variety of hazardous and non-hazardous materials could be temporarily stored or permanently deposited. The ventilation system includes a design basis for gassy mine conditions and provides for the option of bulk air cooling and heating.

Jan 1, 1988

By S. K. Kawatra, H. J. Haselhuhn

"Thickening is used during two primary mineral processing operations: water removal and desliming. During water removal, the pulp density is increased through the injection of flocculants. These flocs settle and create a dense pulp while clarified water is removed through the overflow. During desliming, fine particles are removed through the overflow. Desliming can also be used as a mineral separation process known as selective flocculation-dispersion, where valuable minerals are flocculated and gangue minerals remain dispersed and exit through the overflow.There are many ways to analyze thickener performance on a laboratory scale, but these analyses often do not correlate well with full-scale performance. Some pilot-scale systems have been designed using a semicontinuous approach, but the amount of material required to perform their tests can make semicontinuous pilot thickeners impractical for most applications. This paper focuses on the design and optimization of a continuous pilot-scale deslime thickener that requires minimal material to operate. The design, optimization strategy, and an example study of reagent selection are demonstrated. IntroductionMany laboratory methods have been employed to size and optimize thickener performance. The most common of these include the Coe and Clevenger method and methods derived from the Kynch theory of sedimentation. The Coe and Clevenger method was developed in 1916 and was proven for slurries that do not require flocculation to settle. This method proposed that the settling rate of the pulp is only a function of the solids concentration. It is executed by creating slurries of several different concentrations of solids and performing bench-scale settling tests in graduated cylinders. For each concentration, a thickener unit area can be determined using the following equation (Coe and Clevenger, 1916; Laros, Slottee and Baczek, 2002):"

Jan 1, 2017

By S. S. Huyett

The opportunity to cooperate with the Mining Department of the Pennsylvania State University in their Student-Trainee Program is accepted by The New Jersey Zinc Company who believes that the participation in this type of a program will lead to a larger supply of high calibre engineers in mining. Trainees compete with other employees to earn the cost of their education while gaining practical experience in the mining industry. The practical experience is arranged to complement the technical education through a variety of work assignments. Job opportunities for the trainee are related to the work requirements of the Company and to the performance of the trainee. Management must consider and deal with a good many problems uncommon with regular, full 'time employees. For a number of reasons this program is recommended to other companies as a means to encourage outstanding young men who are interested in a career in the mineral industry to obtain a professiona1 education.

Jan 1, 1963

By Seth T. Reese

THE INJURY DATA and experience at coal mines in the United States for 1951 are presented in this bulletin under the following general heads: (A) General injury experience: Tables 1 to 18: Contain current data on number of fatalities and nonfatal injuries, frequency and severity rates, average severity, major and detailed injury agencies, and distribution of injuries by part of body and days of disability. (B) Selected injury data: Tables 19 to 43: Contain current data on various selected factors of operating and physical conditions that contributed to the occurrence of injuries at bituminous-coal, lignite, and anthracite mines. These factors include extent of hand and machine loading, size of mine by employment and production groups, thickness of bed or vein, duration and number of work shifts, rating of mine as gassy or nongassy, types of cap lamps, explosives, and combination of factors that influence mine safety. (C) Injury experience by States: Tables 44 to 50: Contain current data on number of fatalities and nonfatal injuries, frequency and severity rates, average severity, major causes and principal agencies, injury records of all coal-producing States, and the relative standing by States according to injury-frequency rates. (D) Major disasters: Table 51: Lists the coal-mine disasters that occurred during 1951, giving location, source, and cause. A major disaster in coal mining is defined as a single accident in which or as a result of which five or more men lost their lives. (E) Historical coal-mine injury experience: Tables 52 to 86: Contain data on injuries, injury-frequency rates, employment, and production at bituminous-coal, lignite, and anthracite mines from the earliest records through 1951.

Jan 1, 1955

By Etienne Audibert

No satisfactory theory has yet been advanced to explain what takes place when an explosive is fired in a mixture of firedamp and air. The only means of measuring the' danger is to fire the explosive into the gas mixture and note the effect, but the conditions of firing must be chosen carefully. This report is presented in the hope that it will assist in determining what method to use. The experiments have been designed to show the effect of the principal factors involved in the conditions of firing, and the results give information that seems to have some value.

Jan 1, 1940

By A. Adu-Acheampong

A geotechnical study was conducted to identify the cause(s) of stope instability at the Ashanti Mine (Obuasi, Ghana). As part of the investigation, laboratory testing of rock was performed and the rock mass was classified according to the Q-System (Barton et al., 1974).Numerical analyses were performed using the computer program FLAC (Itasca, 2001). The observed failure zone around the stopes was simulated using both Mohr-Coulomb and Hoek-Brown (Sheorey,1997) models. Yielding along peripheral graphite bands and tensile failure were clearly identified to be the major contributors to stope instability.

Jan 1, 2003

By Jiaqi Jin, Jan D. Miller, Chen‑Luh Lin, Amanda N. Erskine, Shijie Wang

Recovery of metals from coarse ore particles is a great challenge for heap leaching operations of low-grade precious metal resources. Internal fractures of ore particles like micro-cracks can facilitate subsurface transportation of solution inside particles and leaching of valuable minerals. A plant-scale high-pressure grinding roll (HPGR) unit at Coeur Mining’s Rochester mine was operated at selected specific pressures to crush and prepare various products for crack analysis using high-resolution X-ray computed tomography (XCT). 3D shapes of cracks inside ore particles for selected size fractions reveal different damage mechanisms during HPGR crushing regarding particle size and crushing pressure. Close-to-surface cracks formed by abrasion were found in small 2.5 mm particles. Impact cracks with a high aspect ratio were found in particles of larger size and higher HPGR pressure. The volumetric percentage of internal fractures and the specific crack surface areas of selected ore particles are compared to give quantitative conclusions on particle damage by compression during HPGR crushing.

Apr 20, 2024

By Guy R. B. Elliott

If chemical mining is to work, it is extremely important to watch heat balances. Some reactions with coal give off heat and others absorb heat. The reactions of coal with oxygen or air give off heat, but the reactions of coal with steam or with carbon dioxide absorb heat. By balancing the proportions of the two types of reactions, the energy of the coal can be almost completely recovered and environmental damage is minimized. The chemical reactions are listed in Table 1 in the usual form with subscripts (s) and (g) indicating solid or gaseous materials. In reaction 1, solid corbon, C(s), reacts with gaseous oxygen, O2(g), to produce gaseous carbon dioxide, CO2 (g). H means enthalpy or available heat in the material; F is free energy, and it measures whether the reaction can go at all, and if so, how much.

Jan 9, 1973

By Henry C. Freeman

During the early period of the construction of the Illinois and Michigan Canal, about 1838, in excavating for the canal, where the present town of Utica stands, hydraulic limestone was discovered, and its value was recognized. A kiln for calcining and a mill for grinding were erected, and the cement was used in the construction of the locks of the canal. This property was subsequently bought by the present owner, Mr. James Clark, and the work has been continued to the present time in much the same primitive manner as it was begun. The bed is exposed in the Illinois River valley by stripping off a few feet of the covering rock. It is from 4 feet to 6 feet 9 inches thick, and nearly level, dipping gently to the northeast. The Utica Cement Company's establishment, which is two miles west of Utica and two miles east of La Salle, was an outgrowth of the Illinois geological survey. The writer was in charge of the district which included La Salle county, and, in working out the details of the geology of that county, discovered, below the Utica bed, another workable hydraulic limestone, which makes its appearance in the northern bluff of the Illinois River valley, rising above the water level at the point where the company's works are established. This cement group, of which there are several thin beds, lies just below the St. Peter's sandstone, with a few feet intermediate of transition-rock, which appears to represent the Calciferous, and is exhibited in place, in concretionary form, at the top of the bluff. The hydraulic beds are very regular, and the one worked by the company is 10 feet thick; or, speaking more definitely, there are two beds, separated by 18 inches of sandstone, lying about two feet above the bottom, and the two beds are worked as one, the sandstone being first cut out and removed, to prevent mixture. In 1869 I was invited to join with a company, and to take charge

Jan 1, 1885

By G. R. Brunskill

The molybdenite flotation plant at the Magma Copper Co. San Manuel concentrator has been in operation since 1956. In January of 1980, the plant was converted from a hydrogen peroxide-ferrocyanide process to the current sodium cyanide-sodium hydro- sulfide process. This paper is an operational review of Magma Copper Co.'s molybdenite recovery circuit, column cell flotation experience, and use of on-stream X-ray fluorescence analysis.

Jan 1, 1987

By Michael J. Nicol

This paper summarizes some of the results of a study of the reactions involved in the Caron leaching process and identifies the roles of the major dissolved species in the kinetics of dissolution of iron alloy particles formed during reductive roasting. Using rotating disk electrodes and synthetic leach solutions, the reduction of water with the evolution of hydrogen was found not to occur on a dissolving iron surface under typical leach conditions. It has been established that the oxidative dissolution is governed primarily by a reaction involving reduction of Co(III) to Co(II) ions. The reduction of oxygen was also found to make a significant but largely indirect contribution to the kinetics of the dissolution process. The dissolution rates of various iron-nickel-cobalt-copper alloys which simulate the dissolving alloy particles in a Caron plant were measured in synthetic leach solutions under aerobic and anaerobic conditions. The initial dissolution rates of iron, nickel and the iron alloys were found to increase in the presence of thiosulphate, whereas the thiosulphate had a negative effect on the dissolution rates of cobalt and copper. It is shown that the eventual passivation of the iron occurs sooner in solutions rich in Co(II) ions. Whilst these conditions are present in the quench slurry, on-site measurements have shown that due to the very high concentration of reduced dissolved species, passivation does not occur until the slurry is strongly aerated. In the light of these fundamental findings, options for optimizing the rate of dissolution and minimizing the extent of passivation of the iron and iron alloys are discussed. Keywords: Ammonia, leaching, alloy, kinetics, passivation.

Jan 1, 2004

By Clyde Baker

Drilled shafts for many situations offer an economical alternative to driven piles. The Federal Highway Administration (FHWA) has spent considerable time and money in research and developing design and construction guidelines for drilled shafts. However, the full potential of the technology may not be realized because of the uncertainty of the effects of construction on the actual service behavior and the lack of either reliable quality control tests to check for or evaluate defects, or inexpensive load test procedures. Static load testing is very expensive and it is not feasible to load test each shaft on a project. Therefore, other means are necessary to confirm or evaluate the integrity of the completed drilled shaft or to determine the capacity of the completed shaft.

Jan 1, 1989

By Robert F. Kehrman

As part of the Bureau of Mines research on the In-Situ Uranium Leaching, various geophysical resistivity measuring techniques were -evaluated to identify a rapid reliable method for detecting the underground migration of lixiviant outside of the planned limits. Surface and downhole galvanic resistivity and controlled source audio-magnetotelluric (AMT) methods were tested at an in-situ uranium mine in Northern Wyoming during start-up of a new mining area. Downhole galvanic and AMT were the most promising techniques.

Jan 1, 1980

By Steven J. Luzik

Introduction From 1973 through 1986, a total of 12 fires involving oil-flooded rotary screw compressors (OFRSC) were reported to the Mine Safety and Health Administration (MSHA). Most of these incidents were attributed to faulty or by-passed safeguards, or improper maintenance. The cause of a fire in an OFRSC is unique when compared to other types of compressors. A compressor inspection checklist is provided here that can be referenced when conducting regularly scheduled maintenance operations. This checklist and a well-planned program of periodic training and maintenance should help minimize the probability of fires and explosions in OFRSC's. Operation A rotary screw compressor operates on the principle of positive displacement of air. Compressed air in this type of compressor is produced by the meshing of two helical rotors, or screws, as they rotate within a steel housing called a stator. The male rotor normally has four lobes and is driven either directly or indirectly - through a gear assembly - by a motor. It intermeshes with a female rotor having six cavities. Figure 1 explains the compression mechanism: (1) Atmospheric air is drawn into the stator by the suction action of the two rapidly rotating rotors. (2) As the rotors rotate past the intake port, air is trapped in the stator and in the cavities between the rotors. (3) Further movement of the rotors causes an increased reduction in volume, compressing the entrapped air. (4) Compressed air is expelled at the discharge port in the bottom of the stator at a pressure and quantity determined by the particular compressor rotor design parameters, such as length, diameter, and speed. Radial bearings on the male and female rotors compensate for radial loading on the shaft and position the rotors within the stator. Thrust bearings on the discharge end of the compressor prevent rotor misalignment due to thrust developed during the compression cycle. This design prevents the male and female rotors from making contact with each other or the stator. A clearance of 0.07 to 0.1 mm (0.003 to 0.005 in.) exists between the two rotors and the stator. For this reason, there is virtually no wear on the rotors or stator, and the unit is relatively maintenance-free. Oil is injected into the compressor and serves to cool, seal, and lubricate. When air is compressed from atmospheric pressure to some higher discharge pressure, a specific amount of heat is produced. This heat is sometimes referred to as the adiabatic heat of compression. It is partially removed by injecting oil into the compression chamber. Premachined strips - a raised surface on the male rotor and a

Jan 9, 1988

By Guolin Zheng, Jian Pan, Deqing Zhu, Xianlin Zhou

"In ferronickel production, nickel oxide and part of the iron oxide are reduced to metal by agglomeration and smelting in blast furnace. Due to the physical and chemical properties of the laterite ores, a large fraction of fines is generated during the pre-treatment stages and the strength of agglomeration is weakened, which results in low productivity and bad quality. In this paper, the process of pelletization of nickel laterite was developed, and some parameters to strengthen the pelletization of nickel laterite have been optimized. The results show that the compressive strength of fired nickel laterite pellet can reach over 2000 Newton per pellet while firing at the temperature of 1220 °C~1250 °C in 12 min. The product pellet can be used as high-quality burden for blast furnace to manufacture ferronickel.IntroductionIn recent years, the global stainless steel market was developed exuberantly, which greatly promoted the needs of the basic raw material of stainless steel smelting - metal nickel. Currently nickel sulfide ores are only 40% of global nickel reserves, but offer 60% of all the nickel production. However, with the deficit of resources, the nickel sulfide ore (high grade ore) is depleting, so there is an increasing focus on the utilization of low-grade nickel laterite. Recent research has focused on the wet treatment process to utilize nickel laterite, and less on the use of other technologies [1-8]. The economical and efficient technology relies on the reduction of nickel oxide and part of the iron oxide metal by agglomeration and smelting in blast furnace in China. Some domestic steel companies have adopted this process [9, 10]. Unfortunately a large fraction of fines is generated during the pre-treatment stages and the strength of agglomeration is weakened, which results in low productivity and bad quality of fired pellets. In this study, the process of pelletization of nickel laterite was developed firstly, and some parameters to strengthen the pelletization of nickel laterite have been optimized, and the product pellet can be used to produce stainless steel and ferronickel alloy by blast furnace."

Jan 1, 2011

By E. C. Baker

The Bureau of Mines estimated the economic feasibility of investing in a directional hole methane drainage project in the Pittsburgh coalbed for 5 yr in advance of mining. This report estimates the capital investment and operating cost of recovering 325 MMft3 of methane gas per year and the selling price of approximately 317 MMft3 of gas per year. The labor, equipment, and supply requirements were determined from those of a previous directional hole drilled at the Emerald Mine, near Waynesburg, PA. The cost of equipment, materials, services, and labor are in third quarter 1982 dollars. They were obtained from vendors, contractors, and the U.S. Department of Labor. Findings indicate a total capital investment of $1,381,160. Annual operating cost amounted to $167,690. At a wellhead price of $2.05 per thousand cubic feet, the sale of approximately 317 MMft3 of gas per year results in a rate of return on investment of approximately 25 pet.

Jan 1, 1984

By A H. Gray

Gekko Systems Pty Ltd engaged in the test work, design, manufacturing and commissioning of the pre-concentration plant at Silver Standard Resources Inc’s Pirquitas mine in the north western Jujuy province of Argentina. Testing of the ore at coarse feeds of between 2 and 12mm returned probable recoveries of up to a total of 95% silver into 50% of the mass fed to the InLine Pressure Jigs (IPJ’s). The plant has been designed and built based on the test results to include a preparation screen to bypass the fines that are naturally higher in grade and repulping of the coarse which is then pumped to three parallel trains of 2-stage IPJ roughing-scavenging. The target 50% yield to concentrate passes over a dewatering screen and the solids are returned back to the mill feed conveyor. The IPJ tails are transferred to a dewatering screen and solid rejects are stockpiled off the end of a transfer conveyor. All dewatered underflow products are processed via hydrocyclones to recover dirty water for use back into the IPJ circuit and return entrained fines to the fines bypass line.With the sulphide orebody being processed, the results from operations to date have shown that plant performance is matching the original laboratory sulphide ore testwork data. The objective of the pre-concentration step is to both reject gangue and achieve grades between 300-400g/t Ag to the float circuit as flotation recoveries are maximised within this range. The plant currently achieves overall upgrades of approximately 150% of feed grade with the IPJ only circuit producing an average 180% increase from calculated feed grade.

Aug 8, 2011