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By R. D. Sharpe

Gypsum wallboard manufacturers in the United States shipped 3.18 billion m2 (34.2 billion sq ft) of wall-board products during 2004 versus 2.93 billion m2 (31.5billion sq ft) in 2003. Following a historic high production of gypsum wallboard products in 1999, production decreased in 2000. But it has steadily increased during2001 through 2004. Wallboard production in the United States increased about 8.6 percent in 2004 from 2003. Following several years of a “building boom” of new wallboard plants and the expansion of the manufacturing capacity of several existing plants, 2004 was a relatively quiet year. However, several new plants and capacity expansions were announced or are in progress during 2004.

Jan 1, 2005

By David Butts

Solar ponding to crystdlize sodium chloride has been used for thousands of years.1 The systems used were inefficient and usually small compared to the large 25,000 acre pond areas seen today. It has only been in the last 25 years that any real effort has been applied to develop solar ponding technology. Many large solar pond systems have been constructed without much thought to efficient and optimum production rates. The recent high costs of labor, of equipment and of energy have forced producers to take a closer look at their solar pond systems in an attempt to squeeze out the highest possible yields. Other companies such as the Arab Potash Company, the Dead Sea Works, Texas Gulf (Moab, Utah) and San Francisco Salt Companies have no more land area in which to expand and therefore efficient ponds are essential. This paper is written to show how the subdivision of solar ponds can result in production increases of up to 20% and beyond.

Jan 1, 1984

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 S. Jayson Ripke, Shane Hoff

Cleveland-Cliffs’ Northshore Mining Company operates a magnetic iron ore (taconite) concentrator and pelletizer in Silver Bay, MN. These are two recent cost reduction projects: 1. Rougher Magnetic Separators were upgraded throughout the concentrator; throughput and recovery were simultaneously improved. 2. Green Ball Roll Screens on one agglomeration circuit were upgraded from 3.5-inch to 2.5-inch rolls. Throughput improved by 24% from 62 to 77 LTPH. Green ball size distribution improved as an added benefit.

Jan 1, 2005

By Vas P. Srinivasa

A comminution circuit is an important integral part of a mineral processing plant. Nearly 40% of the capital cost and 30 to 40% of the operating cost are taken up by the crushing and grinding circuit. Therefore, considerable care should be given to the design and selection of this circuit. Several factors affect the selection of a comminution circuit--energy consumption, avail- ability of the equipment, the remoteness of location, and availability of trained personnel, to mention a few. Each of these factors influences the choice. Selecting a comminution circuit strictly on lower capital cost may not be optimal. Crushing and grinding circuits are usually site specific and should be selected - only after careful analysis of all the factors involved. The objective of this paper is to show the effect of these factors, which are extranious to capital cost. Usually, the capital cost of a semiautogenous grinding circuit is lower than that of an equivalent conventional circuit. However, due to lower equipment availability and high power costs in certain locations, the economic advantage of lower capital cost is lost. Analysis indicates that a break even point occurs at a power cost of 5¢/kWh. This paper describes the procedure utilized for selecting the most economic comminution circuit and states the conditions applicable for each cominution circuit.

Jan 1, 1983

By F. H. Nehl

The U.S. Bureau of Mines investigated the selective electrowinning of Ag and Au from cyanide solutions contaminated with Cu with the goal of decreasing the amount of Cu co-deposited. Decreasing Cu co-deposited will reduce refinery costs. Direct current was applied to the cell in pulsed and square wave voltages at 0.7 A?h per 150 mL of solution. Times tested for each cycle ranged from 1 to 10,000 ms. Graphite, lead, and stainless steel were evaluated as electrode materials. Square wave e1ectrowinning at 70? C gave the best separation of Ag and Au from Cu. Applying 2.5 V during the duty cycle, 0.0 V the rest of the period, a duty cycle of 10 to 30 pct, and a period of 100 ms to 1,000 ms gave the following results: Ag concentrations decreased from 34 µ g/mL to 0.1 µ g/mL, Au concentrations decreased from 54 µ g/mL to 0.2 µ g/mL, and Cu concentrations remained almost constant at 560 µ g/mL.

Jan 1, 1993

By James Humphrey

There is a natural resistance to change in any form. When it comes to implementing a game-changing technology like autonomous haulage on an operating mine site, the resistance can at times appear insurmountable. Whether based on real information or misguided preconceptions, it?s essential that we don?t underestimate the effort it will take to overcome this resistance, while clearly recognizing when it?s worth the effort. These realizations did not happen overnight for sites where autonomous haulage has been implemented. Nor did they happen overnight for manufacturers of autonomous mining equipment. Caterpillar, for example, began building toward autonomy more than 30 years ago and had a truck operating in the mid-1990s. Lessons learned during those early years led to the realization that there was much more to be learned ? not just about the machines themselves, but about the systems and knowledge that must be in place for a successful implementation. Working closely with customers, initiating real-life demonstrations on mine sites, having discussions with regulatory agencies and other stakeholders ? these and many other activities were necessary before autonomy could be fully and successfully launched. After decades of effort, Caterpillar?s first official commercial autonomous mine site went to work in 2011 in Farmington, NM.

By L. B. Hales

The advent of the process control computer with its capabilities of monitoring, storage, and real-time control has revolutionized control technology in the mineral industry. Initial efforts to introduce the computer into process control began in the early 1960&apos;s. However, it wasn&apos;t until the last decade with the introduction of integrated circuits and minicomputers that truly successful applications became visible. Computer hardware and real-time operating software have improved to the point that they rarely provide major problems in the implementation of successful control systems. At this time the most prevalent problems and obstacles affecting the successful implementation of a control system are as follows: (1) reliable and representative sampling systems; (2) rugged and reliable process sensors; (3) the availability of well-defined control strategies; (4) the willingness of plant management to provide the continuous support necessary to acquire and/or train appropriate personnel in the operation and maintenance of advanced control systems. Discussion of these problems and of the instrumentation required for the successful application of computers in minerals processing plants follows. In order to enhance this discussion the remainder of this subsection is broken up into individual mineral processing categories.

Jan 1, 1979

By Deepak Malhotra

INTORDUCTION Mining operations are unique In that they handle large volumes of water (millions of gallons) daily. The water contains dissolved metals, processing chemicals, organics, and other contaminants, There are several sources of water contamination at mine sites: mines, mills, tailings ponds, and Industrial/utility complexes. Utility waste water generally represents a very small portion of the total process water utilized in a normal milling operation and hence will not be addressed in this paper. Mine drainage can represent a significant amount, thus having an Impact on the recovery of metals, especially In Industrial minerals operations, and may have to be treated separately. The National Pollutant Discharge Elimination System (NPDES) effluent limits are becoming more stringent, thereby requiring mining operations to treat process water prior to discharge to the environment. The general trend Is to move toward a closed-loop waste system and treat only that small fraction of process water which Is to be discharged to public lands. The following section discusses the reasons for waste water treatment and the existing and emerging technologies for meeting NPDES effluent limits. REASONS FOR WATER TREATMENT Due to the diverse nature of the mineral Industry, process/waste water contamination problems as well as processing flowsheets are site specific. However, certain generalizations can be made specific to processing of different minerals: • Acid mine drainage Is a problem at sulfide/coal mines. • Cyanide contamination of water Is a problem at gold processing plants. • Organics can be a problem at mines using flotation oils. • Tolling ponds are generally acidic at sites processing industrial minerals such as silica sand and feldspar. The cost for water treatment Is viewed as an added cost of production. Hence, large mines are moving toward dedicating personnel to management of water resources in order to minimize waste water for treatment. Very often, mines having closed-loop water systems will treat waste water for reasons other than meeting NPDES regulations. These Include situations where process requirements dictate use of high-quality water for separation of minerals, neutralization of acid mine drainage water, and portable water for the mill. WATER TREATMENT TECHNOLOGIES Water treatment process has to be cheap and simple because It has to process large volume, and It does not directly add to the bottom line, namely revenue. The water treatment process development has to be site specific because the contaminants In the water vary from site to site. and discharge limits for water vary from state to state. The current technologies for wastewater treatment have been divided Into the following three areas: • Removal of heavy metals • Cyanide destruction • Scale control A brief summary of the current technology In each area Is discussed below. Removal of Heavy Metals The physical and chemical processes for heavy metal removal are summarized in Table 1. The most common and cheapest approach has been the precipitation of hydroxides at high pH followed by sedimentation and thickening of solids. The remaining solids can be removed by filtration. The pH is adjusted back to neutral, and the water Is discharged. This process is most commonly used wastewater treatment technology in the mining industry. The basic processes can be modified by combining other operations in order to meet the objectives of the specific site as illustrated In the following examples: • AMAX&apos;s Mt. Emmons treatment facility uses Lectro Clear® process where the precipitated solids are removed by electroflotation. • AMAX&apos;s Climax Mine water treatment plant used Ion exchange columns to meet the discharge limits on molybdenum.

Jan 1, 1992

By Jae-Chun Lee, Sadia Ilyas

"The present study was carried out to develop an economically feasible and environmentally friendly technique to extract metals such as Al, Fe, Cu, Zn and Ni from electronic scrap by employing Penicillium chrysogenum strain KBS3. Studies were carried out in various leaching modes, including one-step leaching with combined growth and leaching phases (Mode 1), two-step leaching with alternative growth and leaching phases (Mode 2), spent medium leaching with separated growth and leaching phases (Mode 3), leaching with fresh growth medium without fungal culture (Mode 4), leaching with deionized water (Mode 5) and leaching with commercial organic acids (Mode 6). The main lixiviants produced in leaching Mode 1 were citric, tartaric, oxalic and gluconic acids in concentrations of 12, 2.5, 1.8 and 152 mM, whereas in leaching Mode 2, the concentrations were 15, 0.5, 1.0 and 1,162 mM, respectively. In leaching Mode 3, 63 mM citric acid, 23 mM tartaric acid and 29 mM oxalic acid was observed. At 5% pulp density, both leaching Modes 1 and 2 showed similar metal extraction yields from the electronic scrap at 35º C. Approximately 96% Al, 98% Zn, 48% Cu, 25% Fe, 66% Pb and 73% Ni were extracted in leaching Mode 1 in 14 days. In leaching Mode 3, 85% Al, 81% Zn, 97% Cu, 22% Fe, 50% Pb and 63% Ni were extracted in 14 days. The extraction yield of Cu was much lower in leaching Modes 1 and 2 (48- 50%) than in leaching Mode 3 (97%), as well as in leaching Mode 6 (98%) with organic acids, including citric, tartaric, oxalic and gluconic acids.IntroductionTechnical innovations in electrical and electronic equipment with new functionalities and designs stimulate consumer purchasing and lead a rapid increase in the production of waste materials. Terazono et al. (2006) have reviewed the data on electronic waste generation in different parts of the world. Studies by Bertram et al. (2002) have also affirmed that waste electrical and electronic components are the fastest growing waste category, which emphasizes the need for efficient recycling strategies. The recycling of electronic waste is an important subject, not only from the perspective of waste treatment, but also from the perspective of the recovery of valuable materials. However, the recycling of electronic scrap is still limited, due to the heterogeneity of the materials present in the products (Veit et al., 2005).Bioleaching-based processes offer a number of advantages over conventional pyro or hydrometallurgical methods (Lee et al. 2007; Lee and Pandey, 2012). These advantages include simple, inexpensive (in some cases) and ecofriendly approaches and the generation of less active leach residue relative to other metallurgical processes. Although biohydrometallurgical processes have been successfully applied to the leaching of metals from ores (Olson et al., 2003; Rawlings, 2002), data pertaining to the application of these processes for the extraction of electronic scrap are still scarce. Recently, a few studies have been undertaken for the extraction of metals from electronic scrap/ printed circuit boards (Brandl et al., 2001; Faramarzi et al., 2004; Ilyas et al., 2007; Ilyas et al., 2010). These studies were conducted with mesophilic chemolithotrophic bacteria (Acidithiobacillus ferooxidans and Acidithiobacillus thiooxidans), cyanogenic bacteria (Chromobacterium violaceum) or moderate thermophilic bacteria (Sulfobacillus thermosulfidooxidans). However, compared to bacterial leaching, fungal leaching has several advantages, including (i) the ability to grow at a higher pH, thus making it more suitable for the bioleaching of alkaline solid waste; (ii) a generally faster leaching process with a shorter lag phase and (iii) the chelation of excreted metabolites (e.g., organic acids) with metal ions, thus reducing toxicity to the biomass (Burgstaller and Schinner, 1993; Aung and Ting, 2005)."

Jan 1, 2015

By T. Skodack

This presentation will compare actual work site results for the loading and transport of shot rock for two major tunneling projects in North America. "SCARMAR" (the Canadian subsidiary of S & M Construction) is operating a rail bound Hagglund continuous gathering arm loader in combination with a Hagglund nine car shuttletrain system at the West End of Table Mountain on the B.C. Railway project near Tumbler Ridge, Canada. Al Johnson Construction is operating a Hagglund rubber tired continuous gathering arm loader in combination with haul trucks at the Rocky Mountain Pump Storage Project near Rome, GA. This paper will compare: 1) tunnel and ground conditions, 2) the total work cycle as it relates to mucking and haulage 3) efficiencies and related problems with the two systems 4) mucking and haulage rates 5) operating costs, and 6) recommendations for future large tunnel excavations. Manuscript not received in time for publication.

Jan 1, 1983

By J. B. Fletcher

Miami Copper Company has used conveyor belts underground since 1947, At that time, the draw level for a portion of the orebody was only 25 feet above the haulage level To get the main haulage drifts as far away as practical from under the stoping area, 301, belt conveyors were used for lateral transfer, If the haulage drift was kept in good ground., a satisfactory draw of these stopes could be effected in that repairs to the conveyor drifts could be accomplished while drawing ore from the stopes. Some 7,400,000 tons of ore were mined with the 301d belt conveyor at a belt cost of approximately $0,004 per ton of ore. When the mining plan for a new section of the mine was laid. out in 1953, it was decided to use belts to collect the ore from the higher draw levels, and. move the ore laterally to centrally located concrete ore passes for transfer to the main haulage level (See Cut #1), The final plans used belt conveyors too collect from 3 stopes: on the 570 level, 2 stopes on the 720 level, and one stope on the 900 level. The six stopes to be mined in this manner would produce about 8 million tons of ore, and the sequence of mining was such that not more than four 400 feet conveyors would be in use at one time, Four conveyors using 36 inch, 4 ply belting were designed by the mine engineering office and fabricated at the mine shop, so that no piece was longer than 10 feet, and. the heaviest piece was the 25 horsepower motor, The head drive section, and the tail-pulley-takeup section were of bolted construction so they could be broken down for easing moving, Due to the size of the mine openings, the belt had to be transported into the mine in 400 feet rolls, requiring two splices for an installed belt. A torque arm speed reducer was used with a V -belt drive which made it possible to change the speed of the conveyor by changing the diameter of the V-belt pulley (See Cut #2).

Jan 1, 1958

By Wu Xueling

9K medium was used to isolate iron-oxidizing bacteria from 27 sump water samples collected from Dexing Cop-per Mine, Chengmen Mountain Mine and Yin Mountain Mine, Jiangxi Province, China. Lead acetate and silver nitrate were used to enrich metal-resistant iron-oxidizing bacteria from the above water samples. Isolate 16 was isolated from the sample taken at Dexing Copper Mine. Growth experiments indicated that when incubated under lead acetate (3,500 mg/L), isolate 16 still carried out ferrous ion oxidation, while isolate H1, a less resistant strain taken at Yin Mountain Mine, had a tolerance level of only 400 mg/L. When assayed with other metals, i.e., Ag+ (240 mg/L), Hg2+ (0.9 mg/L), Cu2+ (32,000 mg/L) and Mg2+ (22,500 mg/L), isolate 16 still carried out ferrous ion oxidation while, on the other hand, isolate H1 exhibited much lower tolerance levels, i.e., Ag+ (60 mg/L), Hg2+ (0.1 mg/L), Cu2+ (19,000 mg/L) and Mg2+ (13,500 mg/L). Based on 16S rDNA sequence data, isolate 16 and H1 were both identified as Acidithiobacillus ferrooxidans.

Jan 1, 2007

By M. I. F. S. Cruz, R. Pedersen, F. J. A. S. Barriga, A. Dias, A. F. A. Marques

"Underwater hydrothermal vents are known since the 1970s and their importance for the global economy is growing as new discoveries and new assessments are made each year (Cherkashov et al., 2010; Corliss et al., 1979). The similarities of seafloor massive sulfides, representing the younger versions of the well exploited on land volcanogenic massive sulfides, bring an increased awareness to the potential of the sea (Ajan G. Galley, 2007; Hannington et al., 2011; Herzig and Hannington, 1995). The Arctic Ocean presents itself as an opportunity to study new interest areas and numerous hydrothermal systems (active and inactive) were discovered along the Arctic Mid Ocean Ridge (AMOR) (Pedersen et al., 2010b). The Mohns ridge is an ultraslow spreading ridge of the AMOR (Vogt, 1986) where two hydrothermal vent sites were recently discovered, the Jan Mayen and the Loki’s Castle (Pedersen et al., 2010a; Pedersen et al., 2009; Pedersen, 2005). Here we compare these two Arctic hydrothermal systems, which represent two well-differentiated end-members of hydrothermal fields in the region."

Sep 1, 2014

By E. F. Perry

Simulated weathering tests are used to estimate leachate quality of rocks containing varying concentrations of pyrite and carbonates at mines. This study reports the inter-laboratory results from the third phase of a three part effort to develop a standardized, reproducible simulated weathering test for coal mine overburden. Initial development in phases I and II included evaluation of different test apparatus, effects of particle size, gas composition, leaching frequency and other variables. Phases I and II results are reported by Brady et al (2004) and Hornberger et al (2004). In Phase III, a standard column leaching protocol was used by eight commercial, government and university labs to test five rocks of different lithology, pyrite and carbonate content. Ideally, a simulated weathering test should have three characteristics to be useful in mine drainage studies. These include the capability to produce repeatable results, accuracy in simulating field conditions, and a concise test protocol of weeks to a few months. Simulated weathering, or kinetic testing, produces an effluent that simulates mine drainage composition. This can be beneficial for predicting mine drainage quality in comparison to whole rock analyses. The effluent may be tested for the same water quality parameters as the drainage produced during mining, such as pH, acidity, alkalinity, sulfate, iron, manganese, aluminum or other parameters. If the physical, chemical, and biological conditions of the kinetic tests are representative of those found in the mine environment, leachate composition may be used to estimate the water quality parameter concentrations produced during mining. Hornberger and Brady (1998), and Geidel et al (2000), compiled comprehensive chapters on kinetic tests for mine drainage prediction. These sources included: (1) a chronology and synopsis of scientific literature on these kinetic tests as they have developed over approximately 50 years, (2) discussion of the influence of physical, chemical, and biological processes, and (3) general guidelines for test procedures, data interpretation, and recommendations for further research to develop standard methods. Most of the kinetic test methods in use today were substantially developed and applied more than 40 or 50 years ago, including leaching columns (Braley, 1949), humidity cells (Hanna and Brant, 1962), Soxhlet reactors (Pedro, 1961), and field scale tests (Glover and Kenyon, 1962). . The most commonly used kinetic tests for mine drainage prediction are leaching columns and humidity cells. While these kinetic test methods and others have been used in hundreds of mine drainage studies as shown in Hornberger and Brady (1998) and other references (e.g. Sorini, 1997), they have rarely been used in coal mine permitting by either regulatory agencies or the mining industry. The major impediment to routine use of kinetic test methods is the variation in the design and operation of these kinetic tests, and lack of a standardized, accepted (e.g. by EPA or ASTM) test method. Interpretation and data comparison from different studies can be difficult. METHODS Five rocks of varying lithology, mineralogy, carbonate and pyrite content were collected in bulk from Pennsylvanian age coal measures in Pennsylvania, West Virginia and Indiana. Mineralogical composition of the samples was characterized in detail by Hammerstrom et al (in press) using optical, X-ray diffraction, scanning electron microscopy and electron microprobe methods. Acid Base Accounting (Sobek et al 1978; Skousen et al, 1997, Kania, 1998) was performed on bulk samples for % total sulfur (%S) as a measure of pyrite and potential acid generation, and Neutralization Potential (NP) as an index of carbonate content. A modified NP test, following the procedure suggested by Skousen et al, 1997 was also conducted for four of the five samples. The modified NP test accounts for initial acid consumption, Fe oxidation, and subsequent Fe hydrolysis by the iron carbonate mineral siderite. Siderite, even though it is a carbonate gives zero net alkalinity. Lithologic, Acid Base Accounting and general mineral composition data for the five rocks are shown in table 1 (see Appendix). Whole rock elemental analysis for major and trace elements was conducted on a sub-sample of each rock type. One laboratory was contracted to mix, homogenize, and size the bulk samples and prepare sub-samples for all the participating labs. Splits were sent to eight labs, and each organization was provided a detailed set of instructions for column assembly and leaching procedure. The protocol was developed based on results from phases 1and 2 of this study. The principal features of the column assembly are: a specific composition of particle size by weight (table 2), weekly leaching cycles, and incubation under humidified air containing 10% CO2. Figure 1 shows the column construction. [ ] The particle size distribution of the crushed rock sample is largely an artifact of the crushing process, rather than a natural systems process like the particle size distribution of a soil or an unconsolidated sedimentary deposit. The standardized particle size distribution, shown in Table 2, promotes operational consistency of the weathering test procedure, and provides better control over reaction kinetics. Large amounts of fine particles within specific zones of the leaching columns have been found to impede uniform fluid flow and/or gas flow (Hornberger and Brady, 1998). Regarding reaction kinetics, the importance of surface area to volume ratios has been described in a previous phase of this study (Brady et al., 2004), and significant differences in crushed particle size distributions and effective surface areas were found among the lithologic units. Standardizing the particle

Jan 1, 2009

By Ali Nazem, Rennie Kaunda, Zoheir Khademian, Fei Wang, Raymond Henn, Alex Peretiatkol

"The field demonstration portion of the Underground Grouting and Ground Improvement (UG&GI) short course offered by the Colorado School of Mines was held on May 18, 2016 at Baski Inc.’s Yard in Denver, CO.Numerous full field scale demonstrations of grouting methods and equipment were conducted under various field conditions. As part of these field tests, permeation grouting testing and demonstrations were also conducted. Various cement grout mixes were injected into 1.5-m (60-in.) tall transparent sand columns under controlled conditions (Fig. 1). The objective of the sand column permeation grouting demonstrations in the study was to show students the effects of ordinary Portland cement versus ultrafine cement on the engineering properties of the grout, and the permeation height through various types of soil stratigraphic layers in the sand columns. Similar previous demonstrations have had a specific focus on various brands of Type I-II Portland cements and ultrafine cements with a range of water cement ratios and injection pressures. More detailed information about these previous studies can be found in published proceedings (e.g. Henn et al., 2009 -2011).Equipment and material usedThe five clear plastic sand columns were 191 mm (7.5 in.) inside diameter and 1,524 mm (60 in.) tall. Each sand column had a 19 mm (0.75 in.) diameter hole drilled at the base (bottom) of the blind flange for injection of the grout. A perforated plate and/or screen at the base of the sand columns helped to prevent sand from plugging injection port. A ChemGrout grout plant was used for the demonstration consisting of 0.36 m3 (97 gal) high shear (colloidal) tank mixer, a 0.36 m3 (97 gal) agitator tank and a progressive helical cavity pump with maximum output capacity of 77 L/min (20 gpm) at a maximum discharge pressure of 265 psi (18 bar) (Fig. 2). A simple grout header arrangement consisting of control valves, pressure gauges, flow meter, grout delivery and return line, and a short injection line was also custom built. Also used were infra-red thermometers to measure the temperatures of the grout mix batches, CRD and marsh funnels to measure viscosity, baroid mud balance to measure specific gravity, and a digital scale to measure weights. The grout materials used were Holkim Portand cement (Type I-II), Nippon Steel Sumikin superfine cement and U.S. grout ultrafine cement."

Mar 1, 2017

By G. Bonifazi

In the present work the possibility to utilize the morphometrical and morphological characteristics of an articulate solids system in a slurry flow to monitorate and to control a continuous process is considered. This goal has been reached by mean of an optical system able to acquire, to handle and to process the pictorial information derived by a suitable hardware architecture designed to realize the best lighting, focusing and sampling conditions for the examined flow stream domain. The procedure has been tested using different flow stream slurries coming from different sections of a beneficiation plant. A suitable strategy and a consequent software architecture has been set up in order to assure to the system the necessary speed and the stability to achieve correct on-line measurements and control.

Jan 1, 1994

By Lj. Obradovic

The aim of this paper is to study the feasibility of copper and gold recovery from the old flotation tailing dam at Bor, Serbia. Laboratory leaching experiments were carried out using a composite sample taken by drilling from 16 - 40 m depth. Different oxidation agents as FeCl3, Fe2(SO4)3 and H2O2 were used. An H2SO4 solution with a pH less than 3 was used for leaching. The influence of a number of parameters on the recovery of both elements as temperature, pH, duration of leaching and concentration of oxidation agents was also studied.

Jan 1, 2006

According to the previous research, it is found that the thickness of cover is mostly less than 100 m for highwall mining system. However, for most of the Chinese surface coal mines, the mining depth is over 150 m; on the other hand, the shovel-truck is the most common mining technology. As a result, a lot of residual coal will be remained around end-walls. Considering these facts, the calculated methodology of highwall mining system under thick cover is presented in this paper. Meanwhile, numerical simulation of highwall mining system under thick cover was carried out. The outcome shows that the calculated methodology for pillar stability of highwall mining system under thick cover presented in this paper is acceptable. In other words, the highwall mining system is feasible to extract the residual coal around end-walls in Chinese surface coal mines. Thus, not only coal recovery ratio can be improved, but also can increase the production life of surface coal mines in China.

Jan 1, 2012

By R. J. Hickson

From 1993 through 1999 Cyprus Amax Minerals Company successfully completed eight major construction projects around the world. Six greenfield mines were brought into production, an ongoing operation was completely modernized, and an environmental issue was appropriately remediated. The projects stretched over three continents, from arctic Russia to the Atacama Desert, from 16,000feet to sea level, from city suburbs to remote wilderness, from a low of $130 million to over $1 billion. Open pit and underground; mill and leach; gold, copper, molybdenum, and coal were all encompassed. The breadth of diversity experience from these projects inspired Cyprus Amax to create a “best practices” project management protocol, to steer corporate expansion into the next millenium. This paper summarizes those best practices, while high-lighting project management pitfalls to avoid.

Jan 1, 2000