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By G. H. Faye

The prospect of obtaining high-grade concentrates from Canadian pyrochlore ores is rather unlikely, and experimental beneficiation pro-cesses ?appear to have yielded products in the range of 3 to 20 per cent N'b205? A possible solution of the problem is to find an economical chemical method for recovering high-purity Nb2?05 from such concentrates. A technically feasible but economically unproved process is outlined in this paper, in which the concentrate is decomposed by an acid attack and the oxides of niobium and tantalum are isolated and then separated by liquid-liquid extraction. The solution of the ore is adjusted to 7 M HF-5 M HNO3 and the niobium and tantalum are extracted from this solution with methyl isobutyl ketone. The mixed oxides of niobium and tantalum are recovered from the oxdanic phase and dissolved in 0.5 M HF-1.0 M HNO3. Tantalum is extracted preferentially from this solution with methyl isobutyl ketone, leaving niobium in the aqueous phase. By the use of this process it is possible to produce niobium pentoxide and tantalum pentoxi.de in 99.5 per cent purity with a recovery of approximately 95 'per cent, under lab-oratory conditions.

Jan 1, 1957

By M. Misra

Acid mine drainage from reactive sulfide tailings is a major environmental concern facing the mining and mineral industries. A preventive technique to control acid mine drainage by agglomeration and encapsulation process is presented in this paper. The reactive tailings are agglomerated using Portland cement type I1 as binder. The cold bonded agglomerates after specified curing period are, strong and resistance to weathering. The leaching and weathering experiments have shown that a significant reduction in the concentration of dissolved metals can be observed with the agglomerates as compared to as- received tailings. Addition of small amount of sodium silicate during agglomeration increases the strength and develop good resistance to weathering by forming a glassy coating and elongated crystals within the agglomerates.

Jan 1, 1993

By K J. Kidd

There is general understanding of hoisting systems throughout the mining industry. However, the relative importance of the various parameters influencing hoist selection and utilization is not completely understood. In order to determine if these parameters can be identified and prioritized, data covering 613 hoist installations were compiled. The 613 installations represent hoisting systems in 30 countries on six continents. This study compares data to historical trends, correlates design parameters in an attempt to identify underlying selection criteria, and comments on the apparent trends in recent developments in hoist design.

Jan 1, 1998

By L. R., McLeod

NO important changes in metallurgical practice are exhibited in the smelter that has been erected for treating the Morenci concentrate: the material is charged to reverberatory furnaces without roasting, and the matte subsequently blown in Peirce-Smith converters to separate the iron and sulphur from the copper. In fact the process is essentially the same, except for preliminary roasting of the concentrate, that was adopted in the new smelter that was built for the Arizona Copper Co. at Clifton, a few miles away, to treat Morenci concentrate just before the start of the first World War, and which went into service in October, 1913.

Jan 1, 1942

By Vishal Shukla, Prateek Singh, D. P. Chakraborty

"Continuous thickening by an operation called sedimentation is the separation of suspended solid particles from a liquid stream by gravity settling. The primary purpose of thickening is to increase the solids concentration of the feed stream. High rate thickeners are designed specifically to maximise the flocculation efficiency. A detailed investigation has been carried out to understand the influence of ore type and operating parameters such as bed level, bed mass, rake arm torque and flocculent concentration on thickening operation. Tata steel’s Noamundi plant data shows that variation in ore type, and operating parameters are major contributors to fluctuation in thickener performance. A lot of research has been done earlier on thickening operation but effect of ore type and operating variables by using plant data was never touched before.In this context, the performance of thickener was evaluated by daily data to study the influence of ore type and operating variables on thickener operation. Investigation shows that friable ore % in feed mix is proportional to slime density because friable ore is porous & brittle in nature. As a result, friable ore generates more fines/ultrafine during communition process in wash plant. Increase in flocculant concentration and bed mass is showing a positive change on high rate thickener performance Investigation shows that optimum bed mass and flocculant concentration is required to achieve desired pulp density in thickener underflow at different feed pulp density (g/cc).INTRODUCTIONOver the years, Iron Ore Beneficiation at Tata Steel, Noamundi has seen varied changes. Depletion of high grade iron and with increasing iron ore throughputs coupled with lowering of the hard ore a subsequent increase in slime generation, slime management and clear water requirement for wet Plant has thrown up myriad challenges. To overcome these challenges, many improvements initiatives were taken by Tata Steel in last decade. One of the major changes is the recent High Rate Thickener commissioning at Tata Steel Noamundi to cater the high iron ore throughput requirement. Slime reporting to Thickener has increased from 1.4 MTPA 2.5 MTPA over the last few decades. The above changes further aggravate the poor settling and dewatering characteristics of the slurry which is being feed to HRT. Considering the above mentioned constraints and stringent environmental implication proper water management has become a major challenge to reckon with. The thickener is used to increase the concentration of the suspension by sedimentation, accompanied by the formation of a clear liquid. In most cases the concentration of the suspension is high and hindered settling takes place."

Jan 1, 2016

By A Grice

AMC has completed a number of backfill options studies, including several in recent years for large, three-dimensional orebodies involving total extraction by longhole open stoping with backfill. This has led to the development of a thorough review methodology that assists in the selection of the most appropriate backfill system and the most economic mixes to achieve the required performance. A recently developed design tool has simplified the calculation of backfill strengths for various exposure dimensions and automatically determines strengths incrementally over the height of a stope. Using a generic orebody with a plan dimension of 120 m wide by 360 m long, several different stoping layouts have been analysed to determine the effect of stope dimensions and sequencing on backfill strength requirements. This has been done for stope heights from 50 m to 300 m, in 50 m increments. The required strengths have been calculated in slices and summarised for each stope in four equal layers. The average strength requirement for each layout at each stope height has been compared graphically. For all stope heights, a panel stope layout that minimises the proportion of primary stopes results in a lower average strength requirement than grid layouts on a checkerboard pattern. However, for very high stopes, smaller plan dimensions become more economic. The increase in required strength with stope height is non-linear, making taller stopes potentially more attractive. The main cost factor in most backfills is the rate of binder addition, which is closely related to the strength required. By choosing a layout that minimises the backfill strength requirement, significant savings in binder addition rates and overall costs can be achieved. These must, of course, be weighed against other factors to determine the optimum stoping layout and backfill system.

Jan 1, 2000

By Robert E. Moore

Synthetic spinel is proving to be a highly effective refractory for specific applications, but its cost limits applications. Formation of spinel from a raw material such as diaspore or bauxite could provide a suitable and less costly starting material. In the study reported here, finely ground (-325 mesh) diaspore from Missouri and bauxite from Guyana and China are combined with hardburned MgO (-325 mesh) in appropriate proportions to yield spinel and spinel with secondary phases. A classical sintering and creep study was completed, accompanied by a microstructure study to determine completeness of the reactions and morphologies of the reaction products.

Jan 1, 1991

By Michael E. Stout

M.A. Industries, Inc. has developed and is now offering on a commercially available basis, complete systems to recover and recycle lead from spent SLI batteries. The system begins with the breaking and separation of the component parts of the batteries and subsequent treatment of the effluent water produced by this operation. The recyclable materials recovered from this process are metallic lead, lead paste and polypropylene. The lead paste is introduced into a process to convert it from a lead sulfate to a lead carbonate. The process also regenerates the salt solutions into reusable carbonate. The lead carbonate is then leached into an acid bath where it is later recovered by a proprietary electrolytic process. The metallic lead is recovered in a short rotary furnace producing metal for further refining and alloying. The polypropylene is further washed and then introduced to a reclaim extruder along with the proper modifiers and additives. The resulting resin can then be sold on the open market to injection molding processors. This complete system greatly reduces the amount of waste to be disposed of and completely complies with all applicable EPA guidelines.

Jan 1, 1993

By Yasuo Ojima

The mainstream of copper smelting processes in the world today is a combination of Outokumpu type Flash smelting and PS (Pierse Smith) converting process. Presently it can be estimated that about 50% of the worldwide copper production is produced by the Flash smelting process and 80% by the PS converting process. PS converting process due to its operational flexibility and despite its batch character of operation has been widely used in many smelters for more than 100 years. However, an environmental issue has been pointed out related to this process because of the difficulty of handling the fugitive gases. Recently several copper smelters in the world have been newly constructed and others have executed major modification and modernization, The continuous converting process has been applied in many of them instead of PS converting process. This paper compares PS to the emerging continuous converting process and makes a prospect of the future of the copper converting process.

Jan 1, 2003

By G. Keizer

Cortez Gold Mine (C.G.M.) is located in Lander County, Nevada, approximately 80 miles southwest of Elko, Nevada. It is accessed via Nevada State Highway 306 south from Interstate 80. This operation is a joint venture between Placer Dome U. S. Inc. (60% operator) and Kennecott Corporation (40%). The claims which supply oxide and refractory ore feed to the Cortez milling facility are located in both Lander and Eureka Counties. These include the Cortez and Horse Canyon deposits all operated by C.G.M. Joint Venture. Other deposits outside the C.G.M. claim area include; Fire Creek, Buckhorn, Gold Bar and Tonkin Springs. These deposits all occur along the Battle Mountain/Eureka Trend.

Jan 1, 1993

By B. Hester

Many Third World countries of Third World Africa are well-endowed with minerals, especially gold. Political and economic conditions discouraged interest by Western capital for the several decades since colonial rule. Influence from Eastern Block countries has gone and the left wing orientation widely favored by Third World countries has almost disappeared. Under International Monetary Fund influence, these countries now solicit Western finance to expand their industries. Mining is especially encouraged. The paper describes the financing of some recent developments and examines trends and opportunities in some of the more attractive countries.

Jan 1, 1993

By David E. Van Dillen

This volume is a task-by-task review of work performed in modernizing the BMINES finite element code. Much of the discussion is accomplished by cross reference to the user?s guide, which is Volume I of this two-volume report. The computer program described in this report provides for the static, three-dimensional, linear and nonlinear analysis of structural and geologic systems by the finite element method. The nonlinear material properties currently available in the code include isotropic, anisotropic, variable modulus, plastic, viscoelastic, and viscoplastic. Load application capabilities include gravity loading, surface tractions, and initial stresses. The element library includes rods, beams, plane and axisymmetric quadrilateral elements, three-dimensional brick elements, thick shell elements, and plane, axisymmetric, and three-dimensional joint elements. Special features include the ability to simulate excavation and construction sequences by means of element activity. An automatic mesh generator is included in order to simplify input preparation.

Jan 1, 1981

By Stanley Davidson

"The ore deposit mined by Falconbridge Nickel Mines, Limited, is one of the numerous nickel-copper sulphide bodies marginal to the large oystershaped mass of differentiated norite in the Sudbury district, famous as the world's most important nickel producing field. The unique character of the ore deposits of the district has resulted in its intensive geological study over a period of more than 50 years. The results of these studies have given rise to a voluminous geological literature and to a great deal of controversy as to the genesis of the ores. This description of the structural geology at the Falconbridge mine is presented in the hope that it may form a small part of the chain of evidence leading to a reasonably satisfactory explanation of the ore genesis.The mine, named after Falconbridge township in which the deposit occurs, lies along the southeast margin of the norite mass, which, however, is h::re concealed beneath a deep mantle of glacial sands and gravels averaging over 100 feet in thickness. As a consequence, the deposit was not discovered by the early prospectors, and it was not until 1916-17 that E. J. Longyear, of Minneapolis, located the ore by drilling(ll). The discovery was foreshadowed in 1899 by the work of Thomas A. Edison, who found indications of the deposit by what is believed to have been a combination of magnetic and electrical geophysical surveys. He sank a prospect shaft over what has to date proved to be the largest and richest ore section in the mine. A wet quicksand layer at the rock surface proved impenetrable, however, and the 'Edison' shaft never reached bed-rock.The Falconbridge property was acquired by the Lindsley interests in 1928, and ore output, since its inception in 1929, has gradually risen from a modest beginning to the present 2,000 tons and more daily. Total production in this period is 7,500,000 tons of ore averaging 1.72 per cent nickel and 0.89 per cent copper, together with a small but valuable content of precious metals, principally of the platinum group."

Jan 1, 1954

By Don C. White

Santa Rosa is a mid-Tertiary, volcanic-hosted, bulk-mineable, open-pitable, heap-leachable, gold-silver deposit. It is the product of hydrothermal mineralization along an arcuate segment of a caldera collapse ring fault in a probable maar volcanic setting. This segment was later broken by radial faults. Gold occurs principally as electrum finely disseminated through intermediate tuffs, and associated with pyrite, at Santa Rosa. The nearby Alto de la Mina deposit displays stockwork silica-pyrite-gold in a tectonically and hydrothermally shattered andesite flow. Miocene epithermal mineralization was accompanied by central silicification and pyritization and more distal argillization. An andesite flow cap rock at Santa Rosa played a pivotal role as an upward permeability barrier. Highest gold grades and most intense alteration occur closest to the ring faults and immediately beneath the andesite flow. Supergene alteration effects on the gold distribution are minimal.

Jan 1, 1993

By C. Cánepa

In the treatment of many problems related with the optimization of a given ore dressing process, microscopic studies can provide invaluable assistance. Such studies are generally carried out through mineralogical determinations both qualitatively and quantitatively. Frequently the solution of a specific problem requires the combination of these in adequate proportions. Often the nature? of the problem poses some conditions regarding the way the microscopic determinations are made in order to yield useful information. Most publications applied to mineral beneficiation show results of ore microscopy without mentioning the methodological details involved in the determinative work and therefore it is not possible to judge their reliability and/or their relevance. As methodology must necessarily change from case to case, it is very important for the microscopist to identify first the direct and indirect mineralogical information required to solve the problem. Without such guidelines selection of methods for the qualitative and/or quantitative determinations cannot be made.

Jan 1, 1981

By Farhang Hedjazi

Anglo Asian Mining have recently installed an industrial-scale UF/RO plant to treat process liquors from the integrated heap leach/agitation leach/ resin-in-pulp gold ore treatment facilities at their Gedabek gold-copper mine in Azerbaijan. The UF/RO plant is designed to treat 60 m3/h of leach solution to produce discharge quality water. The RO concentrate, which contains elevated concentrations of copper, silver and cyanide, is sent to the company’s SART plant for the recovery of the metal values as a precipitated sulphide concentrate and the cyanide, which is recycled to leaching. The new water treatment plant improves the sustainability of the operations at Gedabek by enabling replacement of fresh water input with RO permeate and safe discharge of permeate to the environment, during periods of excess water balance. The paper includes pilot plant data and early results from the full-scale plant.

By Junji Shibata

Zeolite synthesized from coal fly ash has many intelligent properties such as cation exchange, adsorption, catalyst and so on. The suitable use of the zeolite, however, is not established in an actual commercial scale yet. From the viewpoints of an effective usage of coal fly ash and the zeolite obtained from coal fly ash, we propose the new concept for environmentally friendly usage of zeolite, in which coal fly ash safely returns to the soil with growing plants and purifying wastewater. This method can make great contribution to recycle of coal fly ash, to purification of high nutritious water and to tree planting.

Jan 1, 2002

By D. Nower

"The supply of copper is expected to be at a large deficit in 2012. To recover from these deficits mining companies are required to maximize production and there is no better way to accomplish this than to optimize the use of their mobile mining equipment fleets. To optimize these fleets, each equipment type has to be monitored in its own unique way. Automation would not only improve production, but also minimize the safety risks and eliminate planning errors. The automated vibration monitoring of multiple systems on the shovel can determine the machine’s condition at all times. This reduces unplanned downtime and keeps critical shovels in production. This paper will discuss the details of how shovels can be successfully monitored, continuously. INTRODUCTIONP&H Mining, part of Joy Global, is the world’s largest manufacturer of above-ground mining equipment. Its electric rope shovels, such as Figure 1, with capacities up to 115 tons (104.3 metric tons), are used for high production loading in surface mines; its draglines, such as Figure 2, have bucket capacities to 160 cubic yards (122 cubic meters). P&H also produces blasthole drills, mobile mining crushers and other essential mining equipment. Headquartered in Milwaukee, WI, the company does business on every continent, except Antarctica. ECONOMIC FACTORSDue to the global demands for metals and power, mines are required to operate at full capacity. Mine operations cannot afford any critical assets to shutdown unexpectedly; depending on the ore type and quality, downtime for a single shovel can be as much as $300,000 per hour.Electric rope shovels are one of the most critical assets in open pit mining. They are very large, complex machines with DC or AC motors, multiple reduction gearboxes (some of them complex planetary) and multiple large rolling element bearings. This complexity, combined with the tough 24/7 service, results in too much unplanned shovel downtime, which can affect the entire downstream process."

Jan 1, 2012

By Seungwoo Park, Gaurav Soni, Roe-Hoan Yoon, Hyunsun Do, Kaiwu Huang

In a flotation froth (and foam), air bubbles become larger due to coalescence, causing bubble size to increase, bubble surface area to decrease, and hence casing less hydrophobic particles to drop off to the pulp phase below. Thus, bubble coarsening provides an important mechanism by which product grades are increased. On the other hand, excessive bubble coarsening results in low recoveries. In the present work, a model describing the process of bubbles becoming coarser in a foam as they rise to the top by deriving a mathematical relation between the Plateau border area, which controls film drainage rate, and the lamella film thickness, which controls bubble-coalescence rate. The model has been derived by assuming that liquid drainage rate increases due to slip at the air/water interface, and that the critical rupture thickness is determined by the capillary waves created by thermal motion. The model developed in the present work can predict the bubble size ratio between the top and bottom of a foam as functions of aeration rate, foam height, and surface tension (frother dosage). The model predictions are in good agreement with the changes in bubble sizes measured using a high-speed camera.

Jan 1, 2014

By N. Bakhshizadeh

In this investigation, the aging effect on creep behavior of A12024-10%SiC composite fabricated by powder metallurgy was studied. P/M bars were manufactured by hot powder extrusion method at 450°C with a ratio of 16 to 1. Creep specimens were over-aged at 187 ºC for 43 h. It was found that almost full density composite with relatively homogenous distribution of reinforcing particles throughout the aluminum alloy matrix could be attained by direct powder extrusion process. Creep tests were conducted at temperatures from 275 to 325°C under stresses from 25 to 60 MPa. The analysis of the creep mechanism determined that dislocation glide was the predominant mechanism of plastic deformation. The activation energy of the creep process was found to be higher than that of lattice self-diffusion in pure aluminum.

Jan 1, 2007