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By A. D. Hammond

Until recently, the volumes delivered and unloaded from heap-leaching pads have been estimated by manual methods at Wharf Resources' South Dakota operation. In August 1989, the Engineering Department acquired the MINE-SURVEY software developed by GEM COM Services, Inc. of Vancouver, Canada, as part of a mine planning/grade control software package. The implementation of MINE-SURVEY for pad control resulted in a cost-effective tool to provide accurate and prompt estimates of ore delivered or unloaded from the pads. Volumes can be calculated in a matter of minutes as opposed to hours or days. Another benefit is the ease of comparison of as-build and designed volumes, plotting cross-section in any orientation, importing into AUTOCAD, validation of ore densities and truck factors. This paper describes the application of the MINE-SURVEY systems in heap leaching pad volumetrics.

Jan 1, 1991

By M. A. Trevits

Methane gas is an ever-present problem facing the underground coal mining industry. Mine operators are mandated by law to maintain safe concentrations of methane gas within the mine environment. Ventilation is used by all mine operators to reduce gas concentrations. When gas emissions are such that ventilation alone cannot control the gas, methane drainage methods must be applied. In the 1970's, there was a concern that unprecedented gas emissions would be experienced as mine operators began new developments in the deep and gassy Blue Creek and Pocahontas No. 3 Coalbeds. Such concern was well founded as significant gas volumes are being emitted as these mining operations mature. In 1971, the O.S. Bureau of Mines began to tabulate and track the change in mine emissions. These data were extracted from the underground coal mine quarterly air quality-quantity inspections performed by the Mine Safety and Health Administration. At that time, approximately 6,560 Mm Id (231.7 MMcfd) of gas were emitted from 430 underground coal mines. It was determined however, that the mines emitting less than 2,832 m Id (100 Mcfd) contributed only 2.1 percent of the total daily gas flow. In 1988, underground coal mines emitted 8350 Mm Id (294.9 MMcfd) from 487 mines. This report evaluates the changing nature of U.S. mine gas emissions over the last 18 years.

Jan 1, 1993

By R. L. Merrifield

Cominco Snip is a 60: 40 joint venture of Cominco Ltd. and Prime Resources Group Inc. Cominco manages the operation. The mine site is located in a narrow mountain valley where Bronson Creek enters the Iskut River in Northwestern British Columbia. Access is by air only to the company's 1,500 meter airstrip. Milling at a designed feed rate of 300 tpd began on schedule in January 1991. Tonnage and gold production in the form of bullion bars from the gravity circuit and gold bearing float concentrate have exceeded design forecast. This presentation will examine many of the factors that influenced the final plant design inclusive of exploration findings, bench scale and pilot plant test results, environmental and social considerations, capital and projected operating costs and product transportation alternatives such as the operation's Hovercraft.

Jan 1, 1993

By T. Gonzales

Magma Metals Company operates an Outokumpu Flash Furnace, four Peirce-Smith Converters and two Anode Casting Wheels supported by six Anode Vessels. Process gasses from the Flash Furnace and Converters are treated in a two train/double contact sulfuric acid plant. Sulfur capture for the smelter is +98%. The new flash furnace was commissioned on July 7, 1988 and has processed over three million tons of sulfide concentrate without a major rebuild. Magma has gained unique experience in the operation of the flash furnace at high oxygen enrichments with low off-gas dust loadings. New procedures have been developed to maintain secondary material generation at equilibrium and for maintaining metallurgical control of operating parameters. This paper describes all the procedures, operation control parameters and operating philosophy that has allowed Magma to achieve superior performance.

Jan 1, 1992

By John W. Leonard

The typical tunnel boring machine in use on today's tunnel project uses 15'2-inch diameter cutters at a nominal load of 45 kips per cutter. The cutterhead rotates at a speed of 120 over D revolutions per minute where D is the cutterhead diameter in feet. The typical machine operates about 50 percent of the time. Delivery of a new machine takes 12 to 15 months. The TBM is a specialized tool and not applicable to all jobs. There is a range of job conditions that limit the economic use of a TBM. The machine should provide a thrust per cutter at least twice the compressive strength of rock in psi and up to three times the rock strength is required if in "granitic rocks." The rock strength in psi must be at least three times the cover above the tunnel in feet or the machine may stick. For example, 2,500 feet of cover requires at least 7,500 psi rock to avoid problems. When the RQD's over a significant distance of the project are less than 50, the TBM becomes support-bound. When a large percentage of the time is spent waiting while the ground is supported, the TBM cannot perform well (See Figure 1). This problem increased inversely with tunnel diameter. We are finding that increasing the RPM's does not significantly increase progress. The increased RPM results in a substantial decrease in cutter penetration. The explanation for this decrease appears to be vibration, cutterhead drag, or lack of stiffness in the cutterhead (See Figure 2).

Jan 1, 1981

By A. Janwong

Ion exchange technology is becoming more prevalent for metal recovery from low concentration solutions. The products of ion exchange are typically a metal free stream (product stream) and a concentrated metal stream (byproduct). The metals in the concentrate stream are usually precipitated and returned to the process or discarded. The unique features of emew® technology enable metals to be recovered directly from the concentrated stream. The advantage of the IX-emew® combination is the ability to have two product streams: 1) clean metal free solution and 2) metal product for sale. In addition to recovering metals from solution, it is also possible to separate metals from each other and recover more than one metal product. In this paper, examples of IX-emew® combinations are detailed including the recovery of copper, nickel and cobalt from an industrial waste stream, recovery of nickel from a spent electroless nickel plating solution and recovery of cobalt from an hydroxide cake.

Feb 23, 2014

By B. A. Slaker, T. Miller

"An underground limestone mine in eastern Ohio was experiencing significant floor heave and roof falls, attributed to high horizontal stresses. Areas of the mine showing floor heave were monitored with roof-to-floor extensometers and photogrammetry surveys, to determine the rate and magnitude of heave. Extensometer data were recorded hourly at four locations across adjacent entries while photogrammetry surveys of the floor were performed at the same locations every two to five weeks. A final survey was performed using an I-Site 8200 laser scanner. Following instrumentation, floor heave up to 10.1 cm (4 in) was measured by the extensometers, photogrammetric reconstructions, and laser scanner over a 6-month period. The extensometers were biased by the location where they were placed, failing to consistently capture the location and extent of floor heave and cracking. The photogrammetry surveys were not precise enough to capture small magnitude movements. Mining in the area was halted and within several months the floor movement and incidence of roof falls was significantly lessened. INTRODUCTION Limestone formations in the United States can be subject to relatively high horizontal stresses due to the presence of tectonic loading of the strata. Horizontal stresses have a documented history of causing stability issues in underground limestone mines. Kuhnhein and Ramer (2004) discussed the influence of horizontal stress on complex ground control interactions associated with limestone pillar design and mine layouts. Esterhuizen et al. (2008) documented roof damage observations associated with high horizontal stresses such has roof guttering, beam instability, oval-shaped falls, and failure propagations. There have also been a number of documented case histories of horizontal stress causing unexpected roof and pillar failures at shallow depths (Stacey and Yathavan, 2003). To the knowledge of the authors, there has only been one well-documented case of floor failure causing stability issues in an underground limestone mine. Murphy et al. (2015) documented the role that a weak, moisture-sensitive floor had in the development of a massive roof collapse. For this paper, the study site neighbored, and was in the same general geology of, the site in Murphy et al. (2015). However, the weak, moisture-sensitive floor was not present for the current study. The current study site has experienced significant floor instabilities caused by high horizontal stresses. The instability area was monitored using two different methods to determine if the floor failure would eventually propagate into roof or pillar failure. The objective of this paper is to analyze displacement monitoring measurements from string potentiometers and remote sensing techniques in an area experiencing active movement. Based on the measurement trends and observed damage from inside of the mine, the presumed failure process will be discussed."

Jan 1, 2017

By D. K. Mynear, J. S. Gardner, S. Mittle, A. A. Campoli

West Virginia, although having adequate solar insolation, has witnessed very little actual solar development to date. The reasons for this lack of development are varied, but the primary obstacles to future development appear to be the absence of state-level policies and regulations promoting growth in the solar industry. West Virginia possesses large tracts of under-utilized land throughout the state created by previous mountaintop mining operations that could theoretically be re-purposed for solar farm development. Accomplishing this task will require not only revisions to the current legislation, but also acceptance by utility companies, landowners, and mining companies. Solar developers will need confidence that they can secure revenue from the electricity and Renewable Energy Certificates (RECs) generated by solar projects. Additionally, solar companies will need assurance they will be protected from any non-related environmental liabilities that could arise in the future. The primary avenue in bringing significant solar development to West Virginia will come through large corporate clients demanding or partnering with utility companies for incorporation of solar options into their energy portfolio to help meet established sustainability goals. This scenario has been witnessed in other states where a large client demands renewable options. Solar development could also represent a means through which mine operators might alleviate some of their reclamation and bonding obligations; where the landowner could supplement income from their underutilized land holdings; and where displaced miners could be repurposed in solar installation/maintenance jobs. Utilizing data from the West Virginia Permit Database, this report identifies several mine sites that hold potential for solar development in the future. INTRODUCTION The diversification of energy sources in the United States (US) has seen major shifts during the past decade resulting from: • A sudden abundance of low-cost natural gas becoming available through advanced horizontal drilling and hydraulic fracturing techniques. • Incentive-driven policies leading to new development in alternative energy. • The emergence of renewable energy sources, proliferated by state and federal level incentives and falling capital costs. Coal was once the primary low-cost fuel source for the generation of electricity in the US for most of the last century, providing approximately 50 percent of the total production capacity. However, within the past decade lower-cost natural gas has overtaken coal as the primary source of fuel used in electricity generation, and renewable sources have steadily grown to account for approximately 10 percent of the overall mix.

Jan 1, 2019

By F. J. Murrell

No other region of the world is enjoying the tremendous growth of power use that is currently being experienced in Asia. Fortunately for those of us in the coal industry -particularly in Asia -the preponderance of the power plants being planned or under construction designed to use coal as the power plant fuel. This has produced a significant increase in the demand for steam coal, which has in turn encouraged many of us in the industry to develop new coal mines. One country that has enjoyed very substantial growth in coal production is Indonesia. This developing country of 195,000,000 people who live on the nearly 13,000 islands of Indonesia have emerged very quickly to become the third largest exporter of steam coal, following only Australia and South Africa. Almost all coal in Indonesia is mined by surface mining methods. This paper will examine the surface mining of coal in Indonesia, as it continues to be an important part of the supply equation for coal in Asia.

Jan 1, 1996

By G. Włoch, E. Rudnik

The oxide fraction of industrial zinc ash was characterized in terms of chemical and phase composition, leaching behavior in sulfuric acid solutions, and leaching thermal effect. The waste product contained about 68 percent zinc (Zn), 7 percent chlorine (Cl), 2 percent aluminum (Al) and less than 1 percent other metals, such as iron (Fe), manganese (Mn), calcium (Ca) and silicon (Si). It consisted mainly of zinc oxide contaminated with metallic zinc and zinc hydroxide chloride. The dissolution of metals from the zinc ash was determined for solid-to-liquid ratios ranging from 100 to 500 kg/m3, acid concentrations of 10 and 20 percent, and temperatures of 20 and 40 °C. The best result — 130 g/dm3 Zn(II) at 95 percent zinc recovery — was obtained at a solid-to-liquid ratio of 200 kg/m3, sulfuric acid concentration RI SHUFHQWDQGLQLWLDOWHPSHUDWXUHRI ƒ& 7KH¿QDOVROXWLRQVZHUHFRQWDPLQDWHGPDLQO\E\0Q ,, DQG)H ,,, ions, but the presence of cadmium (Cd(II)) and lead (Pb(II)) ions enabled electrowinning of zinc of about 99 percent SXULW\DWKLJKFXUUHQWHI¿FLHQF\RI WR SHUFHQW /HDFKLQJRIWKHPDWHULDOZDVDQH[RWKHUPLFSURFHVVZLWKUHDFWLRQ heat of about 520 kJ/kg

By E. Watkins, V. Gangrade, P. Zhang, J. Addis, D. W. H. Su, T. Minoski, C. Hollerich, M. Van Dyke, S. Schatzel, H. Dougherty

"This paper presents the results of a comprehensive study conducted by the Centers for Disease Control (CDC), National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Mining Research Division (PMRD) to evaluate the effects of longwall-induced subsurface deformations and permeability changes on shale gas well integrity and safety under shallow cover. NIOSH researchers selected a study site over a southwestern Pennsylvania coal mine, which extracts 1,500-ft-wide longwall faces under 482 feet of cover. One in-place inclinometer well and three permeability monitoring wells were drilled and installed over a 125-ft by 275-ft centers abutment pillar. In addition to the inclinometer well and monitoring wells, surface subsidence measurements and underground coal pillar pressure measurements were conducted as the first 1,500-ft-wide longwall panel on the south side of the abutment pillar mined by the site.A number of FLAC3D finite difference simulations (Itasca Consulting, 2017) were conducted to estimate surface subsidence, coal pillar pressure increases, and horizontal displacements in the in-place inclinometer (IPI) monitoring well. Comparisons of the FLAC3D finite difference simulation results and the surface, subsurface, and underground instrumentation results show that the measured IPI casing deformations are in reasonable agreement with those predicted by the FLAC3D models, and that the measured surface subsidence and underground pillar pressure are in excellent agreement with those predicted by the 3D models. Measured permeability changes were incorporated into a preliminary calculation to evaluate the effect of a hypothetical shale gas well leak on longwall ventilation. Results from this 2018 research clearly indicate that under shallow cover, the measured horizontal displacements within the abutment pillar are at least one order of magnitude higher than those measured in a 2017 study under deep cover and slightly higher than those measured in a 2014 study under medium cover. This research represents a very important step and initiative in utilizing the knowledge and science obtained from mining research to improve miner and public safety as well as the safety and health of the workers in the oil and gas industries"

Jan 1, 2019

By R. J. Hickson

The giant El Abra copper mine project under development in Northern Chile will come on stream in early 1997 at a production rate of 500 million pounds of cathode copper annually. Ownership is 51 % Cyprus Amax and 49% Codelco. Cyprus Amax has construction responsibility. Total project cost is $1050 million. El Abra will incorporate latest operational technology with labor efficient practices to achieve world class productivity levels and low initial cash costs of about US $0.35/lb copper. Development procedures for the almost 800 million ton oxide deposit, as well as the hydrometallurgical processes selected for recovery of the copper values are discussed. Construction costs and pertinent technical data are shown.

Jan 1, 1996

By S. K. Singh

"Feather edging"-a major source of injury and fatal accidents in Australia, South Africa and USA, refers to a phenomenon where the roof, at the goaf edge, falls as a thin wafer of rock often suddenly, over-riding conventional timber breakerlines. It may run down and affect adversely a working bord at distances of 15 metres or more from the goaf edge. Feather edging typically occurs in relatively massive, strong roof strata such as sandstone or conglomerate. This paper presents the results of a mine trial where a concentrated row of fully grouted bolts were able to resist the feather edging in the first comprehensive, monitored trial in an Australian pillar ('total') extraction coal mine.

Jan 1, 1999

By A. L. Wilder, S. N. Dixon

Introduction Coeur d'Alene Mines Corp.'s largest precious metals property is located in the historic Rochester Mining District 40 km (25 miles) northeast of Lovelock, NV. The property encountered cold weather operational problems soon after its fall start-up in 1986 due to its elevation of over 1830 m (6000 ft). The problem of ice buildup on the heaps because of sprayed solution application was faced immediately. It was felt that allowing ice to build up all winter long until a spring thaw was impractical due to the large area under leach. Further, the operating cost and delivery schedule for a solution heating system was unacceptable. The development and installation of a leach solution distribution system using drip emitters made efficient, cost-effective winter operation possible. Other benefits of this system have also been observed and are discussed here. General process description 15,422 kt/day (17,000 stpd) of - 1.27-cm (-1 /2-in) crushed ore from the three-stage crushing plant are delivered to the leach pad using 77.1 t (85 st) rear dump haul trucks. The ore is drifted into place with a D-9 bulldozer. Leach panels are contiguous and are approximately 8861 m'(90,000 square ft) in area built in 6-m (20-ft) lifts. New panels are built on top of older areas to a final height of 61 m (200 ft). Each panel is ripped and cross-ripped prior to leaching. Barren solution is distributed to the heap using drip emitters at rates of 0.02 to 0.41 L/min/m2 (0.0005 to 0.01 gpm per sq ft), depending on the age of the panels. The pH of the leach solution is 10.7 with a cyanide concentration of 0.75 kg/t (1.5 lb per st). Approximately 50% of the silver and 80% of the gold are finally recovered. Pregnant solution percolates though the heap and flows by gravity into one of two 9.46 ML (2.5 million gal) pregnant solution ponds. The solution is then pumped to a conventional Merrill-Crowe process plant. Clarification takes place in three 9464 L/min (2,500 gpm) capacity filters. The solution is then pumped to a packed vacuum deareation tower for the removal of dissolved oxygen. Typical deareated solution contains 0.7 parts per million dissolved oxygen. Precipitation of gold and silver is accomplished by adding a zinc dust slurry to the deareated solution at the suction of the filter press feed pump. Precipitated gold and silver are recovered in three recessed plate and frame filter presses. Barren solution is discharged into a 11.7 ML (3.1 million gal) pond where cyanide makeup occurs. This solution is pumped back to the heap for further leaching. The precipitate filter cake, containing approximately 75% dore (Ag + Au), is then fluxed with anhydrous borax, soda ash, sodium nitrate and fluorspar to yield a neutral, bisilicate slag. The fluxed precipitate is then charged into a propane-fired melting furnace and heated to 1150° C (2100° F) for 3 1/2 hours. Slag and dore bullion are poured into conical cast iron pots yielding buttons of 800 to 1000 troy oz. The dore typically contains 98.5% silver and 1 % gold. Slag is crushed and tabled to recover the trapped dore blebs and beads. Concentrate from the table is returned to the furnace. Table tails are sent to the crushing circuit and out to the leach pad. Solution application The area kept under leach at Rochester is approximately 130 000 m2 (1.4 million sq ft). Barren solution is delivered to the pad at 21.2 kL/min (5600 gpm) for a resultant application rate of 0.16 L/min/m2 (0.004 gpm per sq ft). A traditional solution sprinkling system using No. 12 Senninger Wobblers with individual pressure regulators was installed at the onset of leaching activities. The Wobblers were placed at 9.1-m (30¬ft) staggered centers and were fed off of a gridwork of Yellowmine plastic piping. Solution flow rates were moni¬tored to each panel. The onset of cold weather with an average nighttime temperature of -12° C (10° F) made it apparent that continual operation would not be possible with the sprinklers. A significant amount of ice was built up on top of the heap, making maintenance and pipe removal dangerous, if not impossible. Leach solution application was restricted to daylight hours to inhibit ice formation. Process plant flow rates were reduced to maintain steady-state operating conditions. However, as daylight temperatures dropped below freezing, ice continued to accumulate due to the sprays. Besides the obvious operating hazards brought on by the growing icefield, there was also the potential environmental hazard associated with an early thaw melting the ice too rapidly for the solution containment facilities. One other option for preventing ice formation was heating of the barren solution prior to spraying. Initial plant design allowed for expansion of the propane storage and distribution system as well as modification of the barren piping for a solution heater. This option was not exercised because the operating costs for an adequate system would have been prohibitive, and timely delivery of a system was not available. An investigation was conducted on the various drip irriga¬tion products available, since subsurface solution applicators would eliminate ice formation altogether. Systems utilizing external flow emitters were ruled out because of their ten¬dency to clog when buried. Emitter systems using perforated tubing were also eliminated from consideration due to their inability to adequately control flow over required lengths of tubing. An in-line emitter system was finally selected which demonstrated clog resistance and adequate flow control, enabling direct burial.

Jan 1, 1990

By J. C. Draper

This subject was introduced last April in a paper presented in Birmingham, Alabama, by James E. Elkin, General Superintendent of Duquesne's Coal Department. This paper will cover some of the same data and in addition it will update and further describe our experience. Our Portal No. 3 was started in June 1965 with battery tractor-trailer face haulage. This mine is operating in the Sewickley seam in Dunkard Township, Greene County, in Southwestern Pennsylvania as shown on Fig. 1. The Warwick group of mines fronts on the Monongahela River and extends westward for some ten miles as shown on Fig. 2.

Jan 1, 1968

By J. M. Smith, T. R. Horton, R. L. Blanchard, T. W. Fowler

INTRODUCTION Uranium mining operations release radioactive materials into both air and water and generate large quantities of solid wastes containing low levels of radioactive materials. Solid wastes produced by mining operations remain on the surface at many inactive mining sites in the Western United States. These mining effluents may present a potential health and environmental hazard. Therefore, Congress, in Section 114(c) of the Uranium Mill Tailings Radiation Control Act of 1978, instructed the Administrator of EPA to prepare a report identifying the location and potential health, safety, and environmental hazards of uranium mine wastes and to recommend a program to eliminate these hazards. Several facts and limitations helped shape the method and approach of the EPA study. Little information on uranium mines was available; measurement information that was available on uranium mine wastes was frequently influenced (biased) by nearby uranium mills; time and resources did not permit comprehensive field studies to provide additional data; and there are inherent variations between uranium mines and sites that complicate generic assessments of mine wastes. To accommodate these facts, the EPA developed conceptual models of uranium mines and made health and environmental projections from them. The models were based upon available data from the literature, supplemented with information from discussions with persons inside and outside the EPA, and by doing several short-term field studies in Texas, New Mexico, and Wyoming. When necessary, conservative (maximizing) assumptions were employed. This paper presents a brief account of a part of the EPA study dealing with the potential health and environmental effects caused by active surface and underground uranium mines. Airborne contaminants are emphasized, although solid and liquid effluents are also included. Due to the limited space, only the methods and parameters used and the results of the assessments will be presented here. Anyone interested in the source of the data used and the development of the parameters should refer to the EPA report (Blanchard et al., 1981). The occurrence and emissions of stable elements were included in the EPA report, however, due to space limitations and their apparent small impact, except for possibly at some specific mines, only radioactive sources will be included in this presentation. MODEL URANIUM MINES The model surface mine was located in the South Powder River Basin of Wyoming and the model underground mine was located in the Ambrosia Lake area of New Mexico. These are the prevalent type mines in those areas. The model mines were based on the average production parameters of the 63 open pit mines and the 256 underground mines that were operating in the United States in 1978 (Department of Energy, 1979) and on a report of an extensive study of open pit mines in Wyoming (Nielson et al., 1979). Information contained in environmental impact statements and in reports from federal and state agencies was also used. Parameters for the model mines are listed in Table 1. The surface mining scenario is that 7 pits are opened in the 17-year mine life with overburden from each successively mined pit used to backfill a previously completed pit, resulting in an equivalent of one pit of overburden (2.4 year production) stored on the surface. No backfilling is assumed at the underground mine. Overburden or waste rock, ore, and sub-ore are separated into separate piles that are either rectangular in shape with length twice the width or in the shape of a frustum of a regular cone. Both shapes have 45 degree sloping sides. To account for bulking, the volume of the material comprising the piles was considered to be 25% greater than the volume of material removed from the ground. It was assumed that dewatering was required at both mine sites. Wastewater discharge rates at the surface and underground mines were assumed to be 3.0 and 2.0 cu m per min, respectively. SOURCE TERMS The following radioactive contaminants at active uranium mines were assessed in the EPA report: 1. Radioactive particulates in a) wind suspended dust from waste rock (overburden) pile, sub-ore pile, ore stockpile, b) suspended dust from mining activities (rock breakage, loading and unloading ore and wastes), and c) vehicular dust, 2. Rn-222 emanation from waste rock (overburden) pile, sub-ore pile, ore stockpile, and mining activities, 3. Rn-222 emanation from mine surface areas, and 4. Radionuclides in wastewater discharged to land surface. Estimated average annual dust emissions (item 1 above) from the model mines are listed in Table 2. Emission factors and the assumptions used to estimate these dust emissions are described in detail in the EPA report. Radioactive source terms were computed for each of the sources; dust emissions were multiplied by the concentrations listed in Table 1

Jan 1, 1981

By G. Heinrichs

This paper is intended to provide information for one to be able to determine the slurry system head curve for pump applications. The slurry characteristics are the basis for what the size, material of construction, and critical carrying velocity of the pipe will be. The system head curve is adjusted by use of the pipe friction coefficient factor and slurry derate factors. An example using multi-staging of slurry pump curves is presented to compare the wear life relationship of pump parts for a tailing pipeline system head curve.

Jan 1, 1996

By L. Rudolphy, P. Tähkiö

"The cPlant is a modular flotation plant which has been designed to minimize capital expenditure and risk. The plant is based on a number of standard modules, for both flotation and ancillary equipment, which can be configured to give the required flowsheet for the ore being treated. All of these modules can be rapidly deployed and erected onsite, minimizing not only engineering time and site preparation but reducing the time taken to get the plant up and generating revenue. Given the paradigm shift in flotation circuit design that has been employed in the cPlant it may allow smaller, previously uneconomic deposits to be exploited and create a more cost efficient upgrade route for existing plants. This paper introduces the cPlant and presents a case study comparing EPC cost and development timing of a cPlant against a traditional flotation circuit design. INTRODUCTION In the development of any mining project the cost associated with process plant engineering, equipment procurement and installation can affect the financial viability of a project. This is of special significance for smaller scale mining projects which perhaps don’t have the mine-life or revenue generation to justify the payback on a modern processing facility. Listening to customer feedback and understanding the challenges that small to mid-sized projects can face lead Outotec to the development of the cPlant. Modularization of mineral processing plants isn’t a new idea with a number of examples being reported in literature for gravity gold (Cabot, Trudel and Cabot, 2001; Gray et al., 2006), dense medium separation (September and Abate, 2006) and even hydrometallurgy (Saario et al., 2013). All these plants have been developed to try to improve on the traditional economics associated with fixed processing plants. Using standardized modules to construct a plant reduces engineering time and design costs which can both be beneficial to the outcome of a project. In addition the modular nature of the plant lends itself to transport to remote sites and rapid installation with only minimal site preparation required. A plant of modular design also has several other advantages over its conventional cousins. Firstly it is relatively easy to expand by duplicating existing modules. Secondly the modules can be treated as building blocks for the process and rearranged if a change in conditions requires flowsheet adjustment. Thirdly, there is potential to disassemble and remove the modular units at the end of the mine life. The ability to easily disassemble, re-pack and transport the plant to a new location not only is important to the long term environmental footprint of an operation but can also be seen as a bonus to an operator that has a number of small ore deposits. If applied in this way modular plants have the potential to create a whole new operating model for previously unviable ore deposits."

Jan 1, 2016

By Y. Numata

2-Mercaptobenzothiazole (MBT) is a heterocyclic-mercaptan and belongs to a group of molecules containing nitrogen and sulfur as electron donor atoms. MBT has been employed as a collector in flotation under names of MBT, Captax, and Flotagen. It is a major constituent of reagents in the 400 series of the American Cyanamid Co. Current applications of the reagent include flotation of copper minerals, tarnished or oxidized lead, copper activated sphalerite, and nickel ores. It has been used successfully in the flotation of pyrite in acid circuits in the range of 4 to 5.

Jan 1, 1990

By J. Kang

Supercritical fluid extraction (SFE) has became an attractive alternative technology to be a new process to recover metal, of which can be substitute the existing Leaching/Solvent extraction processes. Solvent extraction of metallic ions is a technically important and also well-established process that is used in the chemical and hydrometallurgical industries.1 Solvent extraction techniques use the chelation of metallic ions dissolved in liquid solution with organic ligands. Conventional solvent-extraction technique needs large amount of organic solvents and often creates environmental problems.2 More environment-friendly technology is needed nowadays, and there have been increasing attentions to extract metal ions by SFE. CO2 becomes one of the most notable alternative organic solvents due to its nonflammable, nontoxic, nonpolluting, and relatively inexpensive properties with its moderate critical point (73.8 bar, 31.06 °C). Many works have been reported in metal extraction under the supercritical CO2 (scCO2) solvent.3-5 In this study, to recover cobalt from wastes especially from spent lithium ion battery scrap, we selected two ligands ? Cyanex 272 and DEA (diethylamine) for the metal extraction in scCO2. Cyanex 272 is a commercially available extractant along with its series, Cyanex 301 and Cyanex 302. Smart and coauthors measured the metal extracting abilities of these three extractants, and found that Cyanex 301 and Cyanex 302 extracted metal ions much better than Cyanex 272 in the scCO2 solvent.10 The pH of water contacted with high pressure CO2 (70-200 bar, 25-70 oC) is about 2.8-2.95 based on the calculation and the measurement.6-7 Cyanex 272 is known to be less effective as a metal extractant in this low pH environment compared with other Cyanex series. However, when DEA is added to metal extraction reaction with Cyanex-272, DEA works as a strong base to Cyanex 272 converting Cyanex 272 to a deprotonated form (Figure 1), which results in an easy formation of metal complex and the enhanced extraction rate of metal ion.8 Therefore, the purpose of this paper is the metal extraction from spent lithium ion battery waste using scCO2 with Cyanex 272 and DEA.

Jan 1, 2010