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By R. Tanaskovic

Unfavourable climatic conditions in stopes are of significant economic and social importance due to the following reasons: - Working effect is much lower leading to decreased output and work productivity disregarding implementation of mechanization. - Manpower operating capability decreases much faster under unsatisfactory climatic conditions. Under normal climatic conditions a workman would expend much less effort in line with a shorter effective time for the achievement of identical production effects since the work would be more efficacious. The objective of study of problems and climatic conditions is to make the working environment in mines suitable for normal development of operations. Lowering of mining works to increasing depths and winning of a growing number of small orebodies over a broad area makes the problem of creating suitable climatic circumstances more complex. Mining costs are growing due to bench conditions in line with decreasing metal content in the ore, so frequently the investments required for creating favourable climatic conditions represent, in addition to the selection of mining technology, a very important parameter when making decisions regarding exploitation. As known, the basic factors affecting climatic operating conditions in mines-are: temperature, humidity and speed of air flow, implying that the climatic operating conditions are closely related to mine ventilation. Usually, the concept of unfavourable climatic operating conditions includes increased mine air temperature and humidity and low air flow velocity so that heat exchange between human organism and the working environment is impeded or reduced to minimum. Metal mines in Yugoslavia are characterized by the existence of a large number of active faces - stopes and horizons and lowering of mining operations to increasing depths, so that face ventilation solutions are more and more complex. Since its foundation (1961), our Institute is engaged in investigation of factors influencing climatic circumstances improvement of calculations for air distribution and distribution control in complex ventilation networks and study of problems related to ventilation of large volume and irregular configuration faces, as well as application of gained knowledge in our mines. The paper presents the knowledge and experience gained in the case of Lead and Zinc Mine "Trepca" - Stari Trg.

Jan 1, 1980

By D. Kidd, T. Tucker, L. M. Indergard, S. Davis

"INTRODUCTION The Lisbon Valley Mining Co LLC (LVMC) operates the Lisbon Valley Mine located in SE Utah. The mine includes 3 open pits, 150-acre heap leach pad, and solvent extraction electro winning plant (SX/EW). Approximately 25MM tons of ore has been mined since 2005. The ore is stacked on the leach pad to an average height of 55 feet and occurs as a blend of crushed material (minus 2”) and run-of-mine (minus 24”). The host rocks include Dakota and Burro Canyon Sandstones. Copper occurs finely disseminated in this material at an average grade of 0.46%. Minerology is 63% sulfide, 27% oxide, and 10% insoluble. Total inventory mined through 2016 is approximately 230 MM lbs. METALLURGICAL CONSTRAINTS Copper production is constrained by areas of low permeability ore and geochemical issues, including acid consumption. The intrinsic permeability the ore ranges from 10-2 to 1 Darcy. This permeability does not permit sufficient aeration by natural convection, therefore oxygen transport is largely limited to the mass of oxygen that can remain dissolved in leachates. As a result, greater than 50MM lbs of copper remains in inventory and occurs secondary sulfides, including chalcocite, covellite, and bornite. BIOLEACHING FUNDAMENTALS Due to the higher activation energies of secondary sulfides, notably covellite and bornite, a strong oxidant is needed to remove an electron from the metal-sulfide lattice and release the copper cation into the sulfate solution. This process occurs most efficiently using the strong oxidant ferric iron (Fe3+). Ferrous iron can be oxidized to ferric iron by oxygen via chemical oxidation or biologically; which was measured to occur 500,000 times faster when using microbes versus oxygen.1 The microbes that oxidize ferrous iron (Fe2+) to ferric iron are naturally abundant and will develop biomass when appropriate conditions and nutrients present themselves. Most nutrients are provided by the ore/irrigation (P,N,Mg, Ca & Fe2+) while the others (O2 and CO2) are provided by air. In most cases, oxygen transfer is the rate limiting step during copper sulfide leaching. 1 Lacey & Lawson 1970 FORCED AERATION SYSTEM DESIGN This paper describes LVMC’s efforts to bioleach the remaining inventory by forced aeration. Two basic aeration systems were installed and tested including vertical wells and horizontal piping. Vertical System The vertical system was installed using the mine’s blast hole drilling rig. Wells were constructed using 4” high-density polyethylene (HDPE) connected to 4” polyvinyl chloride (PVC) screens similar to conventional bioventing wells. Ore samples were collected at each well location to characterize the spatial distribution of the remaining inventory along with fines (minus 200 sieve), pH (acid consumption), and iron. A block model of each analyte was developed and mapped in 3D."

Jan 1, 2017

By G. A. Dawe, E. G. Kelly

Because of the nature of the breakage in the Barmac vertical spindle impactor, the 80% reduction ratio is very small, so that when an energy efficiency is calculated from Bond's method, it appears to be very low. However, the product size distribution contains a high proportion of fines. It is argued that the production of these fines accounts for the high energy consumption, and Bond's method is modified to account for this, by considering the crusher to be, effectively, a number of smaller crushers in parallel, each having a different reduction ratio.

Jan 1, 1990

By J. S. Gardner, R. Woolacott, P. D. Robinson

In 1917, U.S. Coal and Coke Company, a subsidiary of U.S. Steel, opened Mine 31 and built the community of Lynch, Kentucky. For the time this was truly a major engineering accomplishment. It was documented in Howard N. Eavenson’s 1939 AIME paper, “Coal Through the Ages.” In 1996, Arch Coal donated the Portal 31 property to Harlan County for public use. In 2003 the Southeast Education Foundation, Inc. and the Kentucky Coal Museum plan to open the Portal 31 Exhibition Mine to the public to tell the story of Kentucky coalmining through the decades. This presentation will summarize the history of the project, efforts to bring it to reality, the engineering problems, and the challenges of providing a safe environment for visitors.

Jan 1, 2003

By T. K. McCranie, A. H. Tousley, A. H. Kackman, L. R. Gregory, A. Jr. McElrath, R. J. Krekel

In Roman and earlier civilizations the term cement was applied only to mixtures of lime, pozzolana, sand, water, etc., used as a mortar to bind larger stones. Today, portland cement, the subject of this section, can be briefly defined as follows: The product obtained by finely grinding clinker produced by calcining to incipient fusion (i.e., sintering) an intimate and properly proportioned mixture of argillaceous and calcareous materials. History The Egyptians were probably the first to join building stones with a mixture of sand and a cementitious material (i.e., having the property of or acting like cement). It is generally accepted that the cement used by the Egyptians on such structures as the Great Pyramid was calcined gypsum, Later the Greeks began to calcine limestone for use as a mortar with sand and water. Still later, broken brick and tile were added to the mortar to make the first concrete. The Greeks and Romans found that some sands produced mortars that were especially resistant to the action of water. Hydraulic (i.e., underwater-hardening) cements formed by combining slaked lime, water, and finely divided siliceous materials (e.g., pozzolana) possess superior strength and are capable of resisting the destructive action of water. They were used on the Pantheon, Colosseum, and other structures, some of which are still standing. In 1756 an English engineer, John Smeaton, found that an argillaceous limestone (i.e., containing an appreciable amount of clay as an impurity) produced a cement with greater resistance to the action of water. Despite Smeaton's findings, the use of the old mixture of lime and pozzolana long retained its popularity. Significant contributions in cement technology from England, Swe¬den, France, and Holland were made in the next 68 years. However, the invention of portland cement is generally credited to Joseph Aspdin, an Englishman, who in 1824 patented "portland cement." The name was selected because, on hardening, it resembled the natural building stone from the Isle of Portland, England. The patent features mixing ground limestone and argillaceous materials in appropriate proportions and calcining (i.e., expelling CO2 by roasting) the mixture. This superseded the existing practice of calcining naturally occurring argillaceous limestone. In about 1845 Isaac Johnson, also English, conducted experiments on proportioning the components and calcining them at higher tem¬peratures. His accomplishments are accepted as the beginning of the present-day portland cement industry. The U.S. cement industry originated with the demand for good hydraulic cement for building structures such as the Erie Canal, which was started in 1817. The first discovery of cement rock (i.e., naturally occurring argillaceous limestone with near-optimum ratios of calcium carbonate, alumina, and silica) near Fayetteville, N.Y., was made by C. White. In 1818, White secured a patent for the manufacture of natural cement from that deposit. Subsequently, several natural cement plants were built in 1830-1840 at Rosendale, N.Y., and in the Lehigh Valley of Pennsylvania. David Saylor, who participated in establishing a natural cement plant at Coplay, Pa., in 1850 discovered that a superior cement could be produced by calcining the rock at higher temperatures than hith¬erto. In 1871, Saylor obtained a patent and commenced the manufac¬ture of portland cement. By 1890, there were 17 portland cement plants in the United States with a combined annual output of 62,300 tons. At the end of 1970, the number of plants producing portland cement in the United States (including Puerto Rico) was 169, down from a maximum of 185 in 1967, with total annual shipments of 73.4 million tons valued at $1,298 million. (Fig. 1). In 1970, annual world production of hydraulic cement (which includes pozzolanic materials, hydraulic limes, natural cement, alumina cement, and portland cement, all of which are in current use in various parts of the world) reached 630 million tons (Table 1). Flowsheets of typical U.S. cement plants are shown in Chapter 13. Chemical Composition and Physical Properties It is generally accepted that portland cement clinker consists of a mixture of compounds or synthetic minerals. The four principal compounds are:

Jan 1, 1985

By Anthony W. Wakefield

The paper is intended merely as an introduction to methane hydrates, what they are and why they are important. It does not claim to be a cutting-edge research report, but may be useful for those to whom the subject is unfamiliar.

Jan 1, 2008

By William Cass, Ellen Caftel Turcotte

The Elliot Lake Centre was established in 1965 as an independent Centre for Continuing Education offering a variety of adult education services. In 1976 all retraining and community college type activities were transferred to the Sault College of Applied Arts and Technology which had opened a branch campus in Elliot Lake. Upon the completion of this transfer, the Elliot Lake Centre was then contracted in 1977 by the Canada Centre for Mineral and Energy Technology to study the feasibility of establishing a research and information institute dealing with various health and safety concerns of the uranium worker. By late 1980, a federal charter was granted for the establishment of the Canadian Institute for Radiation Safety, made possible through the cooperative efforts of the Governments of Canada and Ontario, the Ontario uranium mining and refining companies, and the Elliot Lake Centre. On 1 April 1981 the Institute officially began operations. PROGRAM DEVELOPMENT AND COORDINATION In May 1978 the Elliot Lake Centre initiated a voluntary sputum cytology program for uranium workers. This program was financed by the Ontario uranium mining companies: Agnew Lake Mines Limited near Sudbury; Madawaska Mines Limited in Bancroft, and Denison Mines Limited and Rio Algom Limited in Elliot Lake. In 1981 additional funding was granted by Eldorado Nuclear Limited for a small group of employees at the company's uranium refinery in Port Hope, Ontario. Initially in 1978, program participants were accepted according to length of employment, radiation exposure levels (calculated in working level months) and/or smoking history. These restrictions were abolished within a few months and all uranium workers were encouraged to participate. From 1978 to 1979 the sputum cytology program was medically directed by personnel from the Montreal Cancer Institute. Until 1979 all data maintenance for the program was performed manually, however the effort required to sustain the system increased significantly as the number of participants grew. In September 1979 the Division of Thoracic Surgery at the Toronto General Hospital, under the direction of Dr. F.G. Pearson, submitted a proposal to the Elliot Lake Centre to develop a data processing system to help coordinate the surveillance program. In October 1979, Dr. Pearson became the new Project Director. Director of the Cytology Program is Dr. D.W. Thompson of the University of Toronto who is responsible for all cytologic analyses. Developmental work to establish the new surveillance system was initiated in January 1980 and became fully operational at the beginning of March 1981. The following sections describe the Elliot Lake operations of the sputum cytology program now conducted by the Canadian Institute for Radiation Safety. PROGRAM PARTICIPATION As of 1 September 1981 the sputum cytology program has 518 participants enrolled. Eligibility is restricted only to a willingness to participate and the ability of an individual to produce adequate sputum samples. Each participant registers for the program at the Institute and is given personal instruction on methods of sputum collection. The majority of the participants in this program are employed by the uranium mining industry; some work for firms which are contracted by the larger companies. Many participants are either retired from the work force or receive disability pensions or workmen's compensation benefits. Other participants have been employed in the uranium mining industry and have since gone on to other employment; some work for various federal and provincial governmental agencies concerned with the mining industry. Some participants are referred to the program by their family physicians because of smoking histories and/or various respiratory conditions. A small number of these individuals have never been involved in the mining industry at all. A chart describing program participation by employment is found in Appendix 1. PROGRAM REGISTRATION In the Elliot Lake area, persons interested in registering in the program are required to go directly to the Sputum Cytology office located at the Canadian Institute for Radiation Safety. Each individual is interviewed personally by the Program Officer. For the employees of Agnew Lake Mines, Madawaska Mines and the Port Hope refinery of Eldorado Nuclear Limited, registration is possible during the Program Officer's semi-annual on-sitevisits. Participants are assigned, in chronological order, "program numbers" for easier identification. File labels are color-coded according to place of residence or, in some instances, place of employment. Each file is stamped with the date each sample bottle is distributed. A file contains: all original test results, a completed registration

Jan 1, 1981

By Keith Jones, Martin Knights, Timothy Watson

In 1996 a KBR (Brown and Root) led international JV was appointed to design and supervise an underground and surface package. The design of 6 km of tunnels, plus enlargements, deep shafts in glacial and sandstone deposits for the conversion of the existing LEP underground laboratory at CERN, Geneva adjacent to the Jura Mountains/Lake Geneva had to be undertaken in an operational environment and in conjunction with other underground constructions associated with the US$3bn refurbishment.

Jan 1, 2003

By S. E. Phillipson, S. Romberger

The Late Miocene San Cristobal Ag-Zn-Pb deposit represents syngenetic and epigenetic mineralization with low- and high-sulfidation characteristics. The geology of the deposit is characterized by barren dacitic ring fracture domes, mineralized resurgent rhyodacite domes, strongly altered and mineralized tuffaceous lacustrine sedimentary rocks and an extensive crystal-lithic tuff debris apron. The orebody is hosted by intracauldron sedimentary rocks and breccias. Fluid inclusion data suggest that silver, lead and zinc were transported as chloride complexes and precipitated by cooling in veins from <5% (by weight) NaCl eq. fluids at 170° to 215°C. Silver spatially and perhaps temporally associated with resurgent rhyodacite was transported as a chloride complex and precipitated by increased H2S activity or increased fluid pH.

Jan 1, 2002

By Reinhold Schulze

Thiourea is being applied as an industrial leaching agent for gold and silver only in a few cases. A CIP technique was developed which eliminates most of the obstacles against its use. Mild conditions for precious metals stripping from the loaded carbon simplifies process conditions in comparison to cyanide CIP technique. Examples are given.

Jan 1, 1998

By B. R. Satio, P. G. West-Sells, D. B. Dreisinger, B. J. Y. Leong, G. A. Kordosky

Electrolytic techniques have historically been used to remove arsenic, antimony and bismuth from copper refining electrolytes. However, both solvent extraction and ion exchange techniques have been heavily researched and in a number of cases commercially introduced. In this study a large number of solvent extraction reagents and ion exchange resins were screened to determine the selectivity of the reagents for impurity removal. Solvating extractants were found to efficiently remove arsenic from electrolyte. The extent of arsenic extraction increased in the following order: TBP < DBBP < DPPP < Cyanex 925 < Cyanex 923. Antimony and bismuth extraction from electrolyte were demonstrated with the reagent 2EHAP04. The ion exchange resins UR-3300 and Duolite C-467 were found to strongly extract antimony and bismuth from electrolyte. C-467 appeared to be superior to UR-3300.

Jan 1, 1993

By Mike O’Brien, Rob Croll

The Evolution of AngloGold -Incorporated in 1944 under the name of Vaal Reefs Exploration and Mining Company Limited -Name changed to AngloGold Limited in 1998 as the vehicle consolidating the gold interests of Anglo American Corporation -Diversification (geographic and orebody) through the sale of low-margin, deep level, short-life assets and the acquisition of higher margin, open-pit and shallow underground operations

Jan 1, 2003

By Gunnar Nord

Shifting ground conditions when tunnelling often call for different methods of attacking the tunnel face. In order to overcome problems with local unstable soft ground in a hard rock tunnelling project the Boodex method offers a cost effective alternative. Boodex and variants of it is a combination of two well-known techniques, drilling with Boomer rig using Odex gear. It will give a steel lined hole ready for grouting and the steel pipe has a load bearing capacity that means that a spiling effect is achieved. In this paper the method and some applications will be described with possibilities and limitations.

Jan 1, 2003

By W. K. Collins, C. L. Dahlin, D. C. Dahlin, W. K. O’Connor, G. E. Rush

Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155°C; P002=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to investigate the appropriate feed characteristics, identify the process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

Jan 1, 2001

By Stephen P. Winkelmann

The expansion of gold production in Nevada&apos;s Carlin Trend over the last few years has been staggering. To increase gold production while minimizing capital requirements and providing for the safe and efficient mining and processing of ores has required a tremendous effort by the mine engineering group at Newmont Gold. Organizational changes were implemented by the company to effectively deal with a full range of engineering problems. Specially developed computer software and its applications will be explained in this article as well as improvements in the techniques used in converting geologic resources into reserves. Scheduling procedures for the mining of multiple pits to feed multiple processing facilities will likewise be presented. Ore control procedures and current mine engineering practices are discussed. Growth at Newmont Gold Expansion of production levels at Newmont Gold Co. was brought about primarily by the economic incentive to exploit increased reserves. From 1987 to 1989, mined production increased by 260%, gold production by 238%, and manpower by 166% (Table 1). These increases came quickly and demanded

Jan 1, 1990

By J de Cuyper, N. R. Tipman, G. E. Agar, L. Laré, W. Freyberger

The flotation chemistry of the commercial INCO matte separation process was investigated. The slow cooling of Bessemer converter matte forms discrete phases of Cu2S and Ni3S2 and a Cu-Ni alloy. After magnetically removing the alloy, the Cu2S and Ni3S2 are separated by flotation at pH 12.4 (saturated lime) using diphenyl guanidine (DPG) as both collector and frother. DPG has been used exclusively in this flotation process because of its unusual selectivity for copper minerals. The surface product resulting from chemisorption of DPG onto the Cu2S was identified as the double salt Cu(DPG)2SO4,.CU(DPG)2(OH)2. The adsorption followed Langmuir behaviour up to a monolayer coverage. In the absence of DPG, the rapid adsorption of oxygen by Cu2S in flotation pulps was observed. The surface product was identified as the insoluble basic copper sulfate CuSO4.3Cu(OH)2 with the production of sulfate ion. In the presence of DPG, the oxidation reaction appears to be suppressed. The frothing properties of DPG and commercial frothers were compared. DPG is not a powerful frother. Batch flotation tests confirmed that DPG is a highly selective collector when compared to most sulfhydryl collectors.

Jan 1, 1976

By D. S. Choi

The paper contains a subsidence measurement taken over a room and pillar panel of a mine located in northern West Virginia. A total of 72 monuments were used to determine a three dimensional view of mine subsidence. In addition, the results of measurements were used to compute ground strains with the use of a numerical model.

Jan 1, 1982

By E. L. McHugh

Digital camera and computer technologies can be used to monitor mine slopes and provide real-time warning of rock falls. NIOSH researchers assembled a surveillance system using low-cost video cameras and computer software from the security industry to test its effectiveness. The system is designed to signal an alarm when motion is detected and to record images of the scene. Masking can restrict motion detection to specific areas within the camera view; sensitivity is adjustable. The time-stamped images provide a record that can help reconstruct and quantify an event. Video motion detection can augment standard monitoring methods to increase safety in surface mines.

Jan 1, 2004

By S. Gundiah

Preparation of functionalized polymers from the polymerization of monomers and preformed polymers are discussed with a few illustrative examples. The methods of their characterization, with reference to their application in flocculation, are described.

Jan 1, 1987

By Kenneth Denton, Michael Cutts, Andrew Bursey, Eric Eisold

Phase III of the Orme Street Combined Trunk Relief Sewer project connects two existing 2.13 m diameter combined sewers to a new 3.66 m diameter relief sewer at 7locations along a 970 m alignment in downtown Atlanta. The alignment was enveloped by adjacent structures and utilities. The project was constructed below the groundwater table through compressible residual soil, rock and mixed face using a myriad of construction techniques, including compressed air NATM and jet grouting. Numerous design and alignment changes and accommodations for existing utilities and conditions were made during construction. The authors believe this to be the ?rst NATM project in North America utilizing compressed air tunneling.

Jan 1, 2003