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By S. J. Jung

The most frequent causes of accidental injury and fatality are carelessness and ignorance; and the most common accidents are haulage accidents, fall, drowning, and fire. However, in this modern day and age, severe injury has become the dire consequence of an ever-increasing number of industrial and mining accidents as well as sport-, military- , etc. Mine accidents have declined dramatically in number and severity through decades of research, technology, and preventive programs. However, preventing recurrence of disasters like those of the past remains a top priority requiring constant vigilance by management, labor, and government. The goal of the present research is to investigate and identify root causes associated with types of mining accidents (victim being caught by an equipment, bodily motion, over exertion, etc) and nature of injuries such as (sprain and strains, fracture, dislocation, amputation, etc). Further, we hope to discover the impetus of the root causes occurring more and more often in this modern day of technology and quality awareness. With the different dimensions of accidents and injuries brought into the fold, there is the need for researchers and mining operators to comprehend and better still visualize significant patterns of associations among these variables of interest. We assume that, there is a high correlation between many dimensions of nature of injuries and types of accidents. This suggested a principal component analysis to reduce the dimensions for easy and amenable interpretation.

Jan 1, 2012

By Gerald C. Smith

Introduction Newmont Mining Corp.'s Carlin Gold Mining Co. mines gold ore and waste material from four open-pit mines in Northeastern Nevada. Combined production rate is 24.5 Mt/a (27 million stpy). The company is producing gold bullion from the 2.4 kt/d (2600 stpd) Carlin Mill No. 1. and the 2.3 kt/d (2600 stpd) Maggie Creek heap leaching plant. In August 1985, the 6.3 kt/d (7000 stpd) Carlin Mill No. 2 at Gold Quarry came on-line. The total combined throughput of 11.2 kt/d (12,000 stpd) will make Carlin Gold Mining one of the largest US gold producers. Feasibility studies are underway to increase the total gold out-put from Gold Quarry. This will be done by adding a continuous dump-leaching process that will recover gold from lower grade ore. History In 1961, Newmont exploration geologists located claims in the Lynn Creek mining district near Carlin, NV. An exploration drilling program revealed significant gold mineralization. A stepped-up drilling program revealed an ore body with an estimated 10 Mt (11 million st) of ore containing 109 t (3.5 million oz) of gold. Test results in 1963 allowed metallurgists to develop the flowsheet and design for a 1.8-kt/d (2000-stpd) countercurrent decantation (CCD) cyanide plant. Carlin Gold Mining Co. was formed to operate the property. Carlin purchased its first mining equipment in 1965. This consisted of two Bucyrus-Erie 2.7 m3 (3.5 cu yd) shovels and nine 27.2 t (30 st) Wabco Haulpak trucks, two Inger¬soll-Rand track-mounted drills, one Chicago Pneumatic T-650 rotary drill, one rubber tired Michigan 280 dozer, one Caterpillar D-8 36A track dozer, one Caterpillar 16 motor grader, and the necessary ancillary equipment. The fleet was capable of mining 3.2 Mt/a (3.5 mil¬lion stpy) working two eight-hour shifts, five days a week. In 1967, one P&H 1500 3.8 m3(5 cu yd) diesel electrical shovel and three 59 t (65 st) Dart trucks were added to the fleet, along with a Chicago Pneumatic rubber tire mounted rotary drill. This equipment addition increased the mining capabilities to 5.7 Mt/a (6.3 million stpy). Three separate pits, the Main, East, and West, within a 1.6-km (1-mile) radius of the Carlin mill were being mined. The crew consisted of 46 hourly men and three supervisors. This equals 497 t/ total hourly manshift (548 st) or 407 t/total manshift (515 st). Rising gold prices in the early 1970s allowed lower grade deposits to be mined at greater distances from the mill. The Boot-strap pit, 19.3 km (12 miles) north of Carlin, was started in 1973. Two Hough 45.4 t (50 st) front-end loaders, four Wabco Haulpak 45.4 t (50 st) trucks, and a second track type D-8H dozer were added. The higher grade ore was trucked to the Carlin mill using three

Jan 11, 1985

By P. Perruzza, R. Grandori, A. De Biase, A. Ciamei, A. Busillo

The Turin metro alluvium soil is mainly made of large boulders, cobbles and gravel , few sand and almost no fines. This grain size curve is out of the range of application for EPB and Slurry TBMs. In order to bore 5 of the total 7,5 kms of Line 1 tunnel, two specially designed Lovat EPB TBMs were utilised in combination with a systematic non structural pre-grouting of a small volume rectangular slab just above the tunnel section. The same pre-grouting was not however applicable for lack of access on surface in some sections of the remaining 2,5 km of tunnel that had to be bored below important buildings/structures, with under ground water pressure up to 1,5 bar, with curves radius of 180 m only. For these more critical sections it was necessary to study and implement a new technical solution and improve the capacity of the TBM to work efficiently in EPB mode even in this unsuitable ground and overall conditions. After months of studies the selected and adopted solution has been to inject inside the cutterhead chamber, in addition to the almost standard foams & polymers additive mixes, a suspension of limestone powders. This with the scope of compensating the lack of fines of the natural ground with rock powders.

Jan 1, 2005

By Augustine O. Orumwense

Ball mills are commonly used for regrinding operations in the mineral processing industry. But, in recent times, efforts are being made at the introduction of stirred mills particularly for those instances where very fine grinding is required. Media type (steel shot, glass beads, alumina balls and crushed quartz), media size, mill speed and the number of passes required to obtained the target product size are studied. The product size and energy consumption are used in the evaluation of the test results. The grinding media size, shape, density, filling ratio, mill circumferential speed and grinding time play a distinct role in product size fineness.

Jan 1, 2005

By R. L. Brown

The Buchans mining district is located roughly at the center of the island of Newfoundland and contains some 18 separate mineral deposits. The first of these deposits was discovered in 1905, the latest discovery having been made in 1979. To the present (1983), some 16 Mt (17.7 million st) grading 1.33% Cu, 7.5% Pb, 14.5% Zn, 115 g/ t (3.7 oz per ton) Ag, and 1.4 g/t (0.04 oz per ton) Au have been mined. Mining operations are now largely terminated, but a few hundred thousand tons of economically marginal reserves may be mined in a salvage operation. The Geological Association of Canada Special Paper No. 22, "The Buchans Orebodies, 50 years of Mining and Exploration," contains papers which describe the history, geology, and the application of evolving geological concepts in exploration. Papers by Neary, Swanson, and Thurlow and Swanson in that volume are topical to the present discussion. Successful exploration techniques at Buchans included physical prospecting, utilization of the state-of-the-art geophysical techniques, saturation diamond drilling which was made possible by the high gross value of the existing ore, and, since 1955, diamond drilling directed by fairly well understood geological parameters. The record of discovery started in 1905 when the Buchans River deposit was found by Matty Mitchell, a prospector employed by the Anglo- Newfoundland Development Co., a British company which owned mineral rights over a very large area in the Red Indian Lake-Exploits River drainage system.

Jan 1, 1991

Soil erosion is strongly related to soil hydraulic properties. Understanding how surface coal mining impacts those properties is important in developing effective management practices to control erosion during reclamation. Soils from undisturbed areas, roughly graded mine spoil, replaced topsoil before seeding, and revegetated areas at the Rosebud Mine in Eastern Montana were evaluated to determine impacts on soil hydraulic properties. Field and laboratory studies were conducted to determine soil hydraulic properties, including particle-size distribution, organic matter content, and saturated hydraulic conductivity. WEPP simulations and risk analyses were performed on the soil hydraulic property data to determine the impacts of changes on soil erosion. The hydraulic properties of the soils in each representative area have significant differences due to the mining and reclamation practices at the mine. WEPP simulations show that the potential for soil erosion increases due to mining activities disturbing the soil. WEPP simulations also indicate that the potential for erosion may return to pre-mining levels over time with effective revegetation practices.

Feb 27, 2013

By C. D. Anderson

A variety of processing technologies exist for recovery from both primary and secondary sources of rhenium. Currently, there are no known primary rhenium deposits, thus, the method in which primary rhenium is produced is dependent on the commodity of which it is a byproduct, e.g., copper, molybdenum, uranium, etc. In addition, focus on the recovery of rhenium from secondary sources, such as alloy scraps and catalysts, is continually growing. This paper presents a review of both primary and secondary processing technologies for the recovery of rhenium. Key Words: Rhenium, Ammonium Perrhenate, Extractive Metallurgy

Feb 27, 2013

By N. A. Abdel-Khalek

The amenability of carbonate separation from a sedimentary phosphate ore using a bioflotation process was studied. Two types of bacteria were chosen for this study. The experiments were performed using oleic acid as collector. The flotation experiments were carried out using statistical designs for optimizing the main operating parameters. A concentrate containing 0.78% MgO and 30.15% P2O5 with a recovery of 92.31% was obtained from a feed containing about 2.45% MgO and 27% P2O5. These specifications could not be obtained using conventional flotation experiments under similar conditions in the absence of bacteria. Measurements of zeta potential, adsorption of bacteria and collector, as well as froth power, were performed to explain the role of microorganisms in the surface modification of both dolomite and phosphate and in their interaction with the collector.

Jan 1, 2009

By H. I. Kim

The leaching of a complex matte in chlorine and chloride media was studied. The matte was prepared from manganese nodules by the reduction smelting-sulfidation route. From XRD analysis, the major phases of the matte were identified as CuFeS2, CuS2, (FeNi)9S8, (FeNi)S2, Ni9S8, Ni3S2, (CoFeNi)9S8 and Co metal. Investigated were the chlorine, hydrochloric acid, hydrochloric acid-oxygen, ferric chloride, ferric chloride-oxygen, cupric chloride and cupric chloride-oxygen systems. The results are discussed in terms of reagent concentration, retention time, leach temperature and gas sparging rate. The chlorination process resulted >99% metal extraction efficiency within a short retention time and at atmospheric temperature. However, there were no preferential extractions of Cu, Ni and Co with respect to Fe. The cupric chloride-oxygen system produced leach liquors with the lowest Fe content and with a high base-metal extraction. Sulfide sulfur was converted to mixtures of elemental sulfur and sulfate in all the studied systems.

Jan 1, 2009

By Horst Pöchhacker

The largest structure along the Tauern highway section between Salzburg and Villach is the 6.4-km-long Tauern Tunnel. The major geotechnical problems that came up surprisingly while driving the headings of that tunnel and their successful solution form the content of this article. A detailed discussion is presented of the special construction methods developed by systematic application of the principles of the New Austrian Tunneling Method with which even very heavily squeezing ground with large excavation areas can be mastered reliably and economically.

Jan 1, 1976

By S. J. Schatzel

Coal mine longwall face ventilation is an important component of the overall mine ventilation system. Increases in the production rate due to higher capacity mining equipment tend to increase methane emission rates from the coal face, which must be diluted by the face ventilation with a minimal opportunity for assistance from additional control equipment (i.e., surface boreholes). Increases in panel length, in some mines approaching 6,100 m (20,000 ft), and panel width provide additional challenges to face ventilation designs. Face ventilation can also be affected by communication with the methane-laden gob gas reservoir. Except in a two-entry system, belt air cannot be used to ventilate the face in the US, except in limited cases. This relatively recent requirement has further challenged the mining industry in maintaining adequate longwall face ventilation. To assess the effectiveness of current face ventilation practices, a face monitoring study was combined with a tracer gas test on a longwall face. The study was conducted at a US mine operating in a thick, bituminous coal seam with some self-heating tendencies. Multiple gob gas ventholes were located near the face and produced a small portion of ventilation air in their production flow. Initial results show that emission rates on the longwall face showed a very limited increase in methane concentrations from headgate to tailgate despite the occurrence of methane delays during monitoring. Increases in methane concentrations in the tailgate entry in the vicinity of the longwall face T-junction appeared to be produced primarily by gas flow from the gob, not from increased emissions from the face. Barometric pressure variations were substantial over the course of the study and varied on a diurnal basis, as is typical of many mining operations. Suggestions are forwarded for reducing longwall face methane concentrations.

Jan 1, 2012

By G. S. Hansford, C. J. N. Dempers, G. E. Searby, A. W. Breed, M. A. Jaffer

The bioleaching of sulfide minerals involves a ferric attack of the mineral with the role of the micro-organisms being the oxidation of the ferrous-iron back to the ferric form, and the oxidation of sulfur, either via thiosulfate or polysulfides, to sulfate. The kinetics of bacterial ferrous-iron oxidation and the chemical ferric leach kinetics of sulfide minerals can both be described as functions of the ferric/ferrous-iron ratio. The independently determined bacterial ferrous-iron oxidation and chemical ferric-iron leaching kinetics have been successfully used to predict continuous bioleaching operations.

Jan 1, 2000

By O. Bernal, G. Velarde

Sociedad Minera Cerro Verde, majority owned by Phelps Dodge produces 200M lbs per year of LME Grade A copper from low cost leaching of secondary sulfides and SXEW processing. Central to the success of Cerro Verde has been the continuous improvement of leaching practices which currently yield over 80% recovery of the contained copper in the ore. This recovery has been achieved by careful attention to operational practices and leaching process fundamentals. This paper details the development of the concept of “Lixiviant Request Rate” where by solution is applied at an optimal rate for the grade, mineralogy, and the point in the leach cycle. Also paramount to the success of Request Rate technology has been the development of irrigation practices such as drip irrigation and irrigation grid design. These developments have ultimately resulted in improved copper production, decreased sulfuric acid and water consumption, decreased pumping cost, and more consistent PLS grades.

Jan 1, 2004

By M. J. Fairweather, J. R. Egan, W. A. Meekel

Cominco Metals, in cooperation with two Canadian Universities and the Government of Canada, is developing applications for column flotation in the treatment of lead and zinc ores. Plant scale results at Polaris and pilot plant studies of Sullivan, Pine Point and Red Dog ores show column flotation to have significant advantages over conventional mechanical flotation for lead and zinc cleaning. Results from these ongoing studies are discussed in relation to ore texture, mineral recovery, impurity behaviour, scale-up and control.

Jan 1, 1988

By D. Symonds, A. J. Richins, M. G. Nelson

Mining activities at Kennecott and Park City are similar in that both districts began operation in the last half of the 18th century, and both operated on a large scale for many years. However, they are different for two important reasons. First, the mines in the Park City district were always underground. The city of Park City was above many of those mine workings. It remained in place after mining activity stopped, and as the town became an up-scale ski resort, property values increased and the tailings dumps became desirable building sites. In contrast, Kennecott eventually became an open pit mine, and the growing pit effectively consumed many of the small towns that had grown up around the underground workings. Even towns on the periphery of the open pit were razed to allow for the disposal of mine overburden. Second, almost all mining activity stopped in Park City in the early 1970s, just as the first rigorous environmental legislation in the United States was enacted. (The Ontario mine operated sporadically until 1982.) Many mine structures, waste dumps, tailings ponds and piles, and tunnels were simply abandoned as the mining companies ceased business or were bought out. Kennecott, on the other hand, has been in continuous operation for more than 120 years, so a closure plan hasn’t been finalized. Nonetheless, environmental and social problems have arisen, and the company has had to address them.

Mar 2, 2022

By R. B. Pedersen, A. Filipa, A. Marques

"Shallow-depth (<200m) high temperature submarine hydrothermal systems are not commonly observed on mid-ocean ridge settings, as most known systems are located within arc - island-arc volcanic settings, often proximal to coastal areas (meteoric waters added). In 2013, during the Centre for Geobiology’s 2013 oceanographic cruise (R/V G.O. Sars), a dredge successfully sampled massive sulfides and hydrothermally altered rocks from the top of a volcanic edifice (~144-284 m depth) located on the northern sector of the Kolbeinsey Ridge. Dredged samples include vesicular altered basalts, and matrix supported anhydrite, barite and barite-pyrite-anhydrite volcaniclastic breccias. Sulfidesulfate breccias depict complex zoning where numerous small vent orifices are distributed with large blades of marcasite that appear intergrown with barite. Native sulfur was observed in one of these small vent orifices. On a microscopic scale, numerous spherical silica-rich structures appear associated to these breccias. These rocks are evidence for the presence of a relatively high temperature (minimum 150ºC) shallow-water seafloor hydrothermal system in the Arctic mid-ocean ridge, far from mainland influence. This new discovery presents a unique opportunity to study the dynamics of fluid chemistry, metal mobility and precipitation in shallow hydrothermal systems. The remote location of this system dictates that fluid recharge will be influenced solely by seawater and magmatic fluids, In July-August 2014 we expect to survey this new field and acquire new and comprehensive data."

Sep 1, 2014

By George Anagnostou

Time-dependent ground behavior may have important implications for the construction process or the life of a tunnel. The paper gives a concise overview of the influence of time on the deformations and the stability of underground openings, including topics such as face stability in soft ground or the time-development of pressure or deformations in squeezing or swelling rock. While keeping in mind practical questions of tunnel engineering, emphasis is placed on understanding the observed time-dependency, on the underlying mechanisms (such as pore water pressure dissipation or chemical processes) as well as on the respective inherent prediction-uncertainties and design-uncertainties.

Jan 1, 2007

By S. Ragab

The objective of flotation models is to predict the recovery rate of minerals from a flotation cell. In this paper a CFD?based flotation models is presented. The model uses first order rate equation, and the collision frequency is estimated using Abrahamson [1] model with input from CFD two-phase simulations. Spatial distributions of dissipation rate and air volume fraction (also called void fraction) are determined by the two-phase hydrodynamic simulations. Knowing these parameters throughout the machine is essential in understanding the effectiveness of different components (rotor, stator or disperser, jets) on the flotation efficiency. Not only the average pulp recovery rate can be estimated but also the regions of high/low recovery rate can be identified. The CFD-based flotation model presented here can be used to determine the dependence of recovery rate constant at any locality within the pulp on particle diameter, particle specific gravity, contact angle, and surface tension.

Jan 1, 2012

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Li-rich red mud was leached using acetic acid to investigate the leaching behavior of lithium followed by neutralizing with hydrochloric or oxalic acid. By neutralizing red mud using diluted hydrochloric acid (0.01 mol/L), 58.04–60.27% of lithium was leached using 25% acetic acid at 95 °C for 60 min. In the meantime, more than 95% of sodium and 85% of calcium were also dissolved in the leachate solution. While oxalic acid (0.5 mol/L) was used to neutralize red mud prior to acetic acid leaching, lithium performed lower leaching efficiencies (42.41–46.88%) in comparison of using of hydrochloric acid–neutralized red mud. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the condition. In this study, 25% (v/v) of acetic acid, at 85 °C for 60 min, was demonstrated as optimum conditions for lithium extraction from oxalic acid–neutralized red mud using acetic acid. The results would be useful and of interest for lithium recovery and purification from red mud.

By Richard E. Gertsch

Mechanical mining holds great promise for the mining industry. Realizing this promise depends on developing the tools needed to mechanize a mining operation with a reasonable expectation of success. Mechanical mining entered the 1990s with new machines, new operating methods and new ideas for the future. Mechanical mining can provide higher production, increase safety, reduce roof support requirements, create smoother openings for better ventilation, substitute continuous production for cyclical drill-and-blast procedures, and create opportunities for automatic and teleoperated control. The full promise of this important technology still lies ahead. Obstacles include: • Long-term production prediction: Mechanical systems have a high capital cost. Although recouped by lower operating costs, the tradeoffs are not always clear to mine operators. • Cutting tools for hard rock: Rock of more than 103.4 MPa (15,000 psi) cannot be cut by flexible mining machines. • Machine designs: Many machines cannot convert the required power into rock cutting capability. • Engineering: Better use of the machines in the mine is needed.

Jan 1, 1994