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By M. Neven, R. A. Steane, E. Lam

"The Key Lake uranium mill is located in Northern Saskatchewan. It treats a high grade, complex uranium and metal sulphide ore. The plant and process are in many respects unique, because commercial treatment of this type of uranium ore had never been done before. The process and engineering design was based on extensive laboratory test results. A pilot plant testing stage was omitted because of confidence in the test results and time constraints to bring the plant into production.The bench scale testwork on exploration drill core samples along with preparation of the feasibility study and environmental impact statement were carried out between 1976 and 1979. The contract for detailed engineering was awarded to Wright Engineers of Vancouver in late 1980 and in August of 1981 following a public inquiry, approval to proceed with construction was granted.Construction began immediately, and during the winter the foundations for many of the plant buildings were poured and by the beginning of the following winter the buildings had been erected and installation of equipment began. Despite a six month construction worker strike in 1982, the crushing plant started up in June of 1983 and ore processing commenced in October of that year, approximately 3 months behind the original schedule.This paper describes the mill design and compares the expected performance, with the operating experience. Emphasis is directed towards flowsheet and equipment changes made since start-up, operational difficulties encountered and further improvements envisaged. Auxiliary systems are only discussed where they directly affect mill operation."

Jan 1, 1986

By John C. Stankus

At the 13th Conference on Ground Control in Mining, a paper was presented detailing a successful test in which a new truss system was utilized, in lieu of wood cribs, for tailgate support in the Pittsburgh seam (Stankus et al., 1994). Since that time, additional tests using this same truss system in the Pittsburgh and other seams are now complete. Also, several mines are now using trusses for full panel tailgate support with no cribs. Through an extensive instrumentation program, much data and new information has been gained from these tests and the full panel usage. From this data, not only have new concepts pertaining to tailgate support been developed, but also for headgate, pillar configuration, primary and supplemental support. In this paper, an update will be presented summarizing the results of these various tailgates.

Jan 1, 1995

By B. Derin, T. Uzunoglu, O. Yücel

In this study, reduction behaviours of Turkish chromite concentrate (48 % Cr2O3, 13.30 % FeO, 18.33 % MgO, 12.37 % Al2O3, 5.76 % SiO2) and nickel oxide by Fe-C alloy in graphite crucible were investigated. In the first stage of experiments, steel scraps were melted in graphite crucibles and were saturated with carbon at 1600 °C and 30 min. In the second stage, mixtures of different amount of chromite concentrate, nickel oxide and flux additives (CaO,SiO2 and CaF2) were charged into the graphite crucible containing the Fe-C alloy and heated to 1600 °C for different reduction times (0-180 min) under argon gas. The highest Cr and Ni con-tents in alloys were found as 11.41 and 14.37 % and the highest Cr and Ni recoveries were found as 88 and94 %, respectively at 180 min.

Jan 1, 2007

This paper highlights the agricultural sector's primary concerns with mining in New Zealand: the information gap, land rehabilitation and compensation. It suggests how these issues can be resolved between the competing land uses in the interests of New Zealand.

Jan 1, 1981

By B. Salt, R. Sullivan, E. Roos, M. de Vries, K. McKenna, L. R. Nelson, M. J. N. Uys, P. Jacobs, E. Munnik, P. Lewarne

A review is presented of the furnace cooling system design and operating developments since the initial furnace start up in January 2001 of the Chambishi DC-arc furnace to produce ferrocobalt alloy. The furnace operating conditions present a number of challenges to the furnace designers and operators in particular to provide a sustainable lining that can withstand the highly corrosive siliceous slag (roughly 50% SiO2). This is exacerbated by the dual requirement to operate this slag in a relatively highly superheated state (?T ? 400°C when tapped at 1550°C) to ensure that the ferroalloy can be tapped (estimated 1370°C alloy liquidus temperature) prior to atomisation. The core design challenge occurs at the alloy-slag interface, where a single refractory type cannot simultaneously meet the dual requirement of both adequate alloy and slag corrosion compatibility. Progression by the fourth furnace campaign to involve a retrofit of the bath sidewall to Hatch high-intensity, water-cooled, copper Waffle coolers and tapblocks is described. This involves operation of the entire slag bath, the slag-alloy interface and a portion of the alloy within a more chemically compatible refractory/slag (and possibly at times even an alloy) freeze-lining. Due to the high furnace power density employed (up to 500 kW/m2 hearth area) coupled with the large slag superheat needed, the resulting imposed peak bath sidewall heat fluxes are substantial, especially in the alloy (typically averaging 170 kW/m2), and on occasion have exceeded 1000 kW/m2. The performance of the Hatch Copper Waffle coolers under such aggressive process pyrometallurgical conditions is described. Aspects of the design and especially operating strategies to effect sustained production at up to 38 MW power input are also discussed.

Jan 1, 2004

By K. Burke, K. L. Myers, R. Espell

Barrick Goldstrike’s (Goldstrike) AA Heap Leach Pad is an HDPE lined facility used for gold recovery from low grade ores using conventional cyanide heap leach technology, operated from 1987 through 1999. Goldstrike prepared a unique reclamation plan for the AA Leach Pad Facility to provide for a cost-effective, environmentally sound facility closure and to fulfill the State of Nevada’s closure requirements. Traditional Nevada leach pad closure has involved rinsing to reduce cyanide concentration to an acceptable level, followed by reclamation. However, certain metals and compounds are not typically reduced by rinsing and some constituents may increase in concentration with rinsing. A closure scenario to effect limited infiltration through installation of a capillary cover for the leach pad was developed. The capillary cover was constructed by placing a fine-grained layer above the coarse-grained spent leach material to create a capillary break. In an arid climate such as Nevada, the fine-grained layer will rarely reach full saturation and the cover will be able to store water during precipitation and allow removal of water through evaporation and transpiration (ET) during the growing season. A 1.22 m (4 ft) cover thickness was selected as the optimum design cover thickness. The drainage network on the surface of the re-contoured AA Heap Leach Pad was specifically designed to enhance the revegetation, reclamation, and sediment yield control aspects of the AA Heap Leach Pad closure, while resulting in a natural looking surface, compatible with the surrounding topography. Adjacent natural topographic features were used to establish target design parameters for re-contouring and erosion control design.

Jan 1, 2001

By T. Hadley, E. Catovic

"Northern Minerals Limited’s (ASX: NTU) flagship project is the Browns Range Rare Earth Project (the Project) located in Western Australia, consisting of a number of deposits with high value, heavy rare earth elements, in particular yttrium, terbium, and dysprosium. The deposits are dominated by xenotime mineralisation, which occurs within hydrothermal silicified and hematitic breccias. The Company delivered an initial JORC compliant resource estimate for the Project at the end of 2012 of 10,500 t of contained total rare earth oxides (TREO), which was increased to 28,084t of contained TREO in October 2013 and further enlarged to 47,997 t of contained TREO in February 2014. Concurrent with the growth of the Project resource base, significant progress has been made in developing the metallurgical process for the beneficiation and extraction of rare earth elements (REE’s) from the xenotime mineralisation. Development of the beneficiation circuit evaluated several process options and selected whole-ore flotation and magnetic separation, followed by flotation (hybrid circuit) as the two preferred flowsheets to pilot, following encouraging results on the bench of 83% and 86% recovery to a 20% TREO mineral concentrate respectively. Several downstream hydrometallurgical extraction flowsheets were evaluated. However, the following two preferred process flowsheets were ultimately selected for further detailed investigation during the prefeasibility study: 1. Sulphation bake, water leach, purification, oxalate precipitation, and/or calcination to produce a mixed RE oxide; 2. Sulphation bake, water leach, phosphate precipitation, caustic conversion, HCl leach, and oxalate precipitation to produce a mixed RE oxalate. Excellent heavy rare earth oxide (HREO) extractions (~ 90%) from beneficiation concentrates were achieved on the bench for both circuits, however flowsheet 1 was ultimately selected as the preferred flowsheet to pilot due to lower capital and operating cost. A mixed rare earth oxalate (42% TREO) or oxide (92% TREO) can be produced with low levels of Th and U of 3 ppm and 6 ppm respectively."

Jan 1, 2014

By S. Kelebek, E. Yalcin

"Two composite samples of a gold-bearing ore from North Western Quebec (Barry Township) were tested to assess their grindability, recovery by flotation and Knelson concentrator as well as extraction using cyanidation.Work index values (BWi) for two composites were found to be 10.4 and 11.0 kWh/tonne, respectively. Flotation tests involved feed samples for which the particle size ranged from a P80 value of 205 ?m to 53 ?m, which resulted in gold recoveries of 91.8% to 95.8% (at gold grades of 130 to 140 g/tonne). Cyanidation tests indicated gold extraction levels ranging from 94.2 to 97.5%. Higher, recoveries were obtained at finer grind sizes and higher cyanide strengths. However, the grind size had a bigger impact on gold leaching. Gold grade and recoveries obtained with the Knelson concentrator device were lower than those obtained by flotation. Mass recoveries to concentrate products strongly depended on the fluidization pressure used. High gold recoveries can be obtained generally at low water pressures of 3 to 4 psi. Higher water pressures produced more selectivity at the expense of higher gold losses.It can be concluded that the gold ore samples tested have good characteristics due to moderate levels of energy requirement, high gold recoveries and extraction rates attainable.INTRODUCTIONBench scale testing of ore samples is an important step in the long series of metallurgical and economic studies involved in bringing new ore bodies into production (Coleman, 1980). Through a laboratory testing program, the behaviour of an ore in a particular process on a larger scale can be established. In an exploratory manner, this testing can be helpful for classification of ores in terms of “good ore” or “problematic ore” by providing preliminary information on recoverability of target minerals. Potential problems if any can be assessed by further investigation of products (e.g., middlings) obtained as a result of testing. A detailed bench scale experimental program in the metallurgical laboratory can also provide the background work for flowsheet development. Depending on the simplicity or complexity of the ore to be tested and type of details required from a testing program, the amount of samples required in the mineral processing laboratory can vary from several kg to more than one hundred kg depending on how detailed the metallurgical testing program is."

Jan 1, 2008

OZ Minerals Limited owns and operates the Prominent Hill Copper-Gold Mine, located 140 km southeast of Coober Pedy in far north South Australia. The Prominent Hill mine comprises an open cut mine with an initial 10 year mine-life and an 8 Mtpa conventional grinding and flotation plant to produce high quality copper-gold-silver concentrates, which are exported by road to local customers and by rail to the port of Darwin for shipment on to Southeast Asian smelters. Mine and process operations at Prominent Hill are licensed to abstract a water supply of up to 26 ML/d, sourced from a borefield located 40 km and extending to 80 km east of the mine. The arid climate of the broader Prominent Hill region means that groundwater is important for sustaining community and pastoral industries in the region, and security of water rights for third party users is a critically important water management issue posing a significant challenge to the development of Prominent Hill. Depth to water table and the typically high salinity of groundwater in the region means there is little environmental dependence on groundwater within the immediate Project area (mine lease and wellfields). The Prominent Hill mine and associated infrastructure lies within the South Australian Far North Prescribed Wells Area (FNPWA), which was principally defined to ensure the ongoing security of the ecologically, socially and culturally significant GAB springs, of which the closest are found around 150 km northeast of Prominent Hill, and only 50 km northeast of the water supply borefield. Prescribing of the FNPWA meant that OZ Minerals was required to demonstrate to both State and Federal Government agencies that the mine's water supply is independent of that which supports GAB springs and other third party water users in the region. Recognising these potential obstacles, OZ Minerals successfully defined and developed a previously unknown industrial quality groundwater resource, separate from other important groundwater resources in the region that supply community, pastoral and environmental users, ensuring third party water user sustainability.

Jun 1, 2010

By Jürgen F. Brune, Liming Yuan, Alex C. Smith

To provide insights and assistances for the optimization of ventilation systems for U. S. under-ground coal mines facing both methane control and spontaneous combustion issues, a computational fluid dynamics (CFD) study is being conducted to investigate the effect of the ventilation scheme on the prevention of spontaneous combustion in longwall gob areas. This report focuses on the flow patterns within the gob under three different ventilation systems; one-entry and two-entry bleederless systems as well as a three-entry bleeder system. The gas flow in the caved gob area is simulated as a laminar flow through porous media while the gas flow in ventilation airways is simulated as a fully developed turbulent flow. The air flow patterns are visualized using flow path lines. Air velocity contours and vector data are also obtained. The possible location of critical velocity zones where the gob is most liable to spontaneous heating is discussed.

By J. H. Zietsman

It has previously been observed that industrial high-titania slags display a compositional invariance, remaining close to stoichio-metric M3O5. The present study focuses on this invariance and the phenomena which may cause it. The invariance was studied using thermochemical calculations and a mechanism is proposed for the observed behaviour. The mechanism suggests that a combination of thermochemical equilibrium and transient slag solidification and melting results in the observed compositional invariance. The proposed mechanism provides new insights and prompts questions about other mechanisms in the smelting process.

Jan 1, 2004

By Todd M. Ruff

The majority of fatalities that occur in road construction work zones in the United States involve a worker being struck by a piece of construction equipment or other vehicle. The Spokane Research Laboratory of the National Institute for Occupational Safety and Health, in cooperation with the Washington State Department of Transportation, is evaluating methods to decrease these accidents. One such method uses devices that assist equipment operators in monitoring blind areas around the equipment to prevent collisions with workers on foot or other objects. Several cameras and sensor systems are available for this application, and a study was conducted to evaluate these systems on various trucks used in road construction and maintenance. Tests were conducted using sanding trucks during the winter months, which allowed researchers to investigate the effectiveness and limitations of various technologies under the most extreme conditions. Tests were also conducted using dump trucks during the warmer months to study the effectiveness of the systems in highway work zones. Results show that many difficulties arise when using camera and sensor systems in cold, snowy climates. And, while the operation of these systems is more reliable during the warmer months, challenges still exist in using them on equipment in crowded work areas.

Jan 1, 2004

The Electricity Generating Authority of Thailand (EGAT) Mae Moh coal mine is an open-cut coal mine in Thailand that produces about 16 Mt of lignite annually to generate 2400 MW of electricity. The surface mine pit covers is 4 km by 7 km with mining depths ranging up to 260 m. A large pit slope is formed with the progression of the mining operation. However, massive slides in the pit slope occur often due to the existence weak planes such as faults and bedding, and the weak mechanical properties of the rocks. Hence, 200 m to 300 m boundaries of rock block including coal seams are left in front of faults in order to prevent slides and maintain the stability of the pit slope. As a result, there are significant coal reserves beneath the abandoned area along the pit slope. Moreover, the mined coal seams are very thick and their thickness range from 15 to 30 m.This paper discusses the application of multi-slicing highwall mining system with stowing to this very thick coal seam left around large pit slopes by means of numerical analysis.

Dec 6, 2010

By Walter Smith

Environmental Quality Committee ?EQC was created in 1995 to facilitate dialogue between industry and northern communities and help build the understanding of the industry in those communities. ?EQC is made up of representatives from 32 northern communities. ?Meet regularly with Cameco to discuss on going and new projects. ?Tour mine sites on a yearly basis.

Nov 1, 2011

By E. R. Maize

[In %-port of Invcstiptionn 7452 ,g dcniing with roof ~wet,ent in the Cmcibla r~ine, rof&apos;erence .,as m.da to the f~ct tiwt timker decny war, bsing studied at tho tine of writing. Thic napor, written a3er completion of that ~tudy, describ~s t1l.e ~mrl&apos;: and sunlharizea the fiats obtained. Ifhen tlle stu* oi roof novement bras be,- at Cxcible tw igeas \%.ere a6-r;incsd. on decay of tiriber Q: scne of :he olficialr;: (I.) 9:la.t timber decay v:as unustmlly rapid in ,tho Ciuoiblc mins, ,m?. ((2) that timber coated with rock ri..~st deixiyad morrl mpirlly thnn those %hat vsrc not so coated. Thsx ::ore no records by which tkeso &apos;iaeas could &apos;L;e tertcc?, ard it cnpsarefi vise to make a limite6 in- vo3tiption, p~.rticu!.ai.ly of +.he effect of roc!< dusting on decny, as rock ductirg is nn importnnt mer-ns of ~rc-,rcnt?;~g cad-dust eql-osions. ]

Jan 1, 1941

By J E. Nethery

At the Red Dome and Mungana deposits in north Queensland, Australia, it is proposed that mineralisation and alteration developed as a &apos;telescoped&apos; overprinting continuum, ranging in style from hypothermal to epithermal, reflecting the major changes that developed in the regional setting over the period circa 325 - 290 Ma. Regional assessment suggests that this also applies to many other precious and base metal deposits within a 40 km length of the host Siluro-Devonian Chillagoe Formation. &nbsp; A ten stage paragenetic sequence of structural preparation, multi phase intrusion and associated mineralisation, alteration and brecciation is postulated for the Chillagoe district.

Jan 1, 1995

By J. Willan

This paper addresses the problem of designing a destress blasting procedure to reduce the incidence of rockbursting in hard rock mines. A review is made of the developed theory and practice of destress blasting in rockburst-prone ground. Specific reference is made to a recent survey of past and current practice with particular reference to Ontario mining operations. The need is identified for a more scientific basis for destress blast design and monitoring. Reference to developments in blasting technology as well as rock mechanics are then made to support a proposed, integrated design procedure and research strategy.

Jan 1, 1984

Case 1: A driller raised a drill rig mast into a 7200-volt overhead power line. Both he and his helper were killed. Case 2: A driller-helper was pulling a winch cable toward a stack of drill steel when the cable contacted a 12,000-volt power line. The helper was killed, and the driller at the rig controls was severely injured. [ ]

Jan 1, 2006

By Douglas Bartley, Brian Wingfield, Robert McClure

Recent studies and limited tests indicate favorable results utilizing high accuracy electronic detonator technology over conventional non-electric pyrotechnic systems. This study discusses the application of this technology using the Daveytronic programmable system in an on-going production basis. The study quantifies the performance as it relates to fragmentation, excavation, vibration and productivity in an eastern U.S. aggregate mining operation. In order to insure accurate data, tight field controls were adhered to during the drilling and blasting process as they related to blast design, bench preparation, pattern layout, drilling and blasthole loading. Following the blast the excavation and crushing procedures were studied to quantify any down stream advantages due to improvements in fragmentation. This study will help provide the industry with information as to the advantages of high accuracy electronic blasting systems over conventional pyrotechnic systems and show the results of an operation utilizing electronic detonator technology through their production season.

Jan 1, 2000

By J. F. Lupo

Leaching operations combine both metallurgical and hydraulic processes to extract metals from the ore heap. In the design of leaching operations, metallurgical tests and simple hydraulic tests are often conducted to define operational parameters such as leach cycle time, application rate, lift height, and effective leach area. While metallurgical constraints are often the primary focus on leach facility design, the hydraulic factors are also critical to the overall success of the operation. Some of the hydraulic factors that are known to impact solution flow through heaps include: • Ore physical and hydraulic properties, • Variation in ore properties under heap loading, • Ore mineralogy and its susceptibility to chemical and/or mechanical degradation, and • Heterogeneities within the heap. This paper presents a discussion on hydraulic factors that may impact the effectiveness of leaching operations. In addition, methods are presented which may be used to assess flow conditions within active and inactive heaps.

Jan 1, 2000