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By J. Ye

A comprehensive flotation study has been carried out on a Chinese fluorspar ore using the packed flotation column developed at Michigan Technological University. The results are compared with that of a conventional mechanical flotation method on the same feedstocks. Key factors controlling flotation performance of both methods are evaluated based upon a simple statistic design. The flotation concentrate produced in one stage of the packed column has 4-S% higher recovery and much lower silica impurity content than that produced by up to six stages when a conventional mechanical cell is used. The results also show that the packed column flotation process is particularly suitable for recovery of finer fluorspar particles.

Jan 1, 1992

By J. P. Gliddon, G. C. Wade, J. W. Lill

Since 1980 a number of significant changes have been introduced at Palabora in an effort to offset the effects of reduced product price and increased unit costs of production. These changes and improvements include major equipment rationalization programs, the introduction of trolley-assisted truck haulage, adoption of a sophisticated computerized truck control system, pit design enhancements, improved drilling practices, use of emulsion explosives, and the installation of an in-pit crushing and conveying system. The various changes, their effect on the operation, and their contribution to cost reduction and improved productivity at Paihbora are considered.

Jan 1, 1987

By J. P. Gliddon

Since 1980 a number of significant changes have been introduced at Palabora in an effort to off-set the effects of reduced product price and increased unit cost of inputs. These changes and improvements include major equipment rationalization programs, the introduction of trolley assisted truck haulage, adoption of a sophisticated computerized truck control system, pit design enhancements, improved drilling practices, use of emulsion explosives and the installation of an in-pit crushing and conveying system. The various changes, their effect on the operation and their contribution to cost reduction and improved productivity at Palabora are considered.

Jan 1, 1987

By James A. Martin

Evaluation and subsequent development of a quarry in east-central Missouri was based on a general but brief examination of outcrops and core from five (5) test holes. Neither core, outcrops, nor existing quarries in the general area gave any indication of potential major problems. In the third year of operation large areas of collapse rubble, consisting of green shale and large blocks of limestone and sandstone, were encountered. Their size and random distribution resulted in both blasting and quality control problems. By the fourth year of operation, production costs became prohibitive and the site was abandoned. Prior to dismantling the plant a geologic investigation, which included shallow seismic and resistivity surveys, was made of the unmined portion of the lease. The collapse dolines appear to be related to structure and predate development of the modern topography. Surface indications of these features are few. The seismic profiles were especially helpful in plotting their distribution. Geologic relationships and seismic data developed at this site are being related to similar suspect areas in Missouri and have been useful in their evaluation.

Jan 1, 1970

By W. E. L. Minter

The most important Witwatersrand gold placers occur on extensive unconformity paleosulfaces that were produced during protracted periods of fluvial degradation. The erosional etches on what was generally unlithified sub-strate indicate that low sinuosity erosion patterns prevailed. The transport systems were dominantly braided fluvial with a minor debris-flow component. The placer sediments were non-cohesive sands and gravels. They were evidently transported by fluctuating, yet perennial, discharges across extensive, low relief braid plains, not far from littoral environments. Progress made in understanding heavy mineral transport processes now emphasizes the importance that selective entrainment probably had in producing concentrations. Cognizance that these characteristics are not unique to the Witwatersrand should be taken into account when designing exploration models.

Jan 1, 1991

By W. E. L. Minter

The most important witwatersrand gold placers occur on extensive unconformity paleosurfaces that were produced during protracted periods of fluvial degradation. The erosional etches on what was generally unlithified substrate indicate that low sinuosity erosion patterns prevailed. The transport systems were dominantly braided fluvial with a minor debris-flow component. The placer sediments were non-cohesive sands and gravels which were evidently transported by fluctuating, yet perennial, discharges across extensive, low relief, bra1dplains, not far from littoral environments. Progress made in understanding heavy-mineral transport processes now emphasizes the importance that selective entrainment probably had in producing concentrations. Cognizance that these characteristics are not unique to the Witwatersrand should be taken into account when designing exploration models.

Jan 1, 1988

By H. H. Murray

The largest reserves of palygorskite in the world are located in Anhui and Jiangsu Provinces in East Central China. The deposits are Middle Miocene in age and range from 3 to 6 m in thickness. The deposits are the alteration product of basaltic volcanic ash. The Chinese Geological Survey estimates the palygorskite reserves are in excess of 200 million tons. The elongate particle shape results in unique colloidal properties. Large quantities are exported to Japan, Taiwan, Southeast Asia, New Zealand, Australia, and West and Gulf Coasts of the United States. The markets include agricultural carriers, paint, joint tape compounds, animal feed binders, catalyst support, drilling muds, and suspending agents for chemicals, pharmaceuticals, and medicines. The viscosity is high and the quartz content is generally 5% or less.

Jan 1, 2009

By Virgil A. Bilyeu

The Pan American Mine, in southeastern Nevada, is about 26 miles west southwest of Pioche, Nevada, and about 266 miles southwest of Salt Lake City, Utah. The mine is located in the Comet Mining District, and since the ore occurrence is generally the same in the Comet and well known adjacent Pioche Mining Districts, the history of the two shall be considered the same. The Pioche District began about 1869 with the production of high grade gold and silver from fissure veins in the Cambrian Prospect Mountain quartzite. Peak production was reached in 1872 and then declined with sporadic production until 1924, when Combined Metals Reduction Co. shipped its first, complex sulphide ores mined from the CM bed at Pioche. Extensive ore bodies in this CM bed attracted interest in the same bed in the Comet District. Small pockets of high grade silver-lead were mined from fissures cutting the CM and other limestone beds above. Exploration in the CM beds at this time proved a large area of mineralization too low grade to be considered ore.

Jan 1, 1967

By H. Hejny

The objective of the project is to construct and operate a pan-European underground drainage and minewater management research centre, which would be the hub for data gathering and dissemination in real time of new data to users for analysis and interpretation, as well as serving as a model for consistency, for other centres at key water management sites throughout Europe which would feed data in real time through the hub. The data from the centre will be essential for informing River Basin Management Plans arising from the EU Water Framework Directive, which is an important driver for the project. The implementation of this Directive sets out a requirement for all Member States to develop River Basin Management Plans for all water resource systems. The facility would be a major contribution to sustainable water management in Europe.

Jan 1, 2007

By E. Pizarro

Division Andina has considered in its long range planning, the exploitation by panel caving method of "Third Panel" mine, which was started its production stage during the second half of 1995. This mine has two production levels, the first is grizzly level and another is L.H.D. level. Both sectors use the same haulage level where mineral is recollected through ore pass. For mineral loading and haulage its use 50ton diesel trucks combined with electro-hydraulic chutes. The automation has permitted what this operation is carrying out with remote control by driver's truck, in concordance to short range planning.

Jan 1, 1998

By R. J. Miller

Mechanized Roof Supports (MRS) have dramatically improved safety and productivity of retreat pillar mining in coal. Due to low capital cost and greater flexibility, retreat panels have in some cases approached the productivity of a longwall. Because of improved safety and rapid set-up time when compared to conventional timbering, MRS are driving a return to retreat pillar mining in many situations. This paper describes how panel layout can be optimized for safety and operational efficiency when using MRS for retreat pillar mining of coal. The potential for significant unit cost reductions will also be addressed.

Jan 1, 1996

By John M. Hill

Automation technology has many facets, some well tested and proven, some yet to be put to the acid test of economic reality. In this paper, we will limit our purview to the former. Consider, if you will, an automated handling system combining high-speed conveyors and automatic devices on-line which not only provide signals for routing and sorting, but also format those signals for the production of manufacturing, inventory, shipping and billing paperwork. This is not futuristic, but practical and a realistic accomplishment. Therefore, the following discussions will address today's challenges not with tomorrow's solutions, but rather, with an established technology which is playing an increasingly prominent role in materials handling systems. Until recently, relatively modest importance has been attached to the timeliness of information feedback from the production or assembly line, warehouse or distribution center. Thus, initial applications of automatic identification equipment focused almost exclusively upon the control of materials flow - that is, routing, sorting, etc. However, these systems have performed successfully and quietly established an enviable track record as reliable materials control tools.

Jan 1, 1973

By D. Piper, J. Noble, M. Richardson, J. Wojcik, L. W. Cope

L. Cope Welcome. I am pleased to see so many people interested enough to stay until this last session of the last afternoon of the convention. Of the people on the panel here, everyone has done everything in placer mining, but we have tried to sectionalize it with each one of us taking a particular portion. Any one of us could probably answer any question. I am very pleased to see some well experienced people in the audience. To start the discussion, Joe, can you give us a brief comparison of pit and drill sampling? J. Wojcik They both have their place. If you expect your deposit is something that is going to have widespread fairly uniform grades, then the pits may be the way to go. If you are going to have something you have to trace for several miles down the river valley, you can't do it with pits and do a proper sampling job. C. McLain Joe, the end result of all of this is to go ahead and mine it if it is a deposit. Do you try to relate your drilling results to something in mining itself against the recovery, because the drilling in different types of ground will give you different kinds of recoveries, and mining in the end is what you are going to do? Do you try to relate this to your mining method?

Jan 1, 1992

By V. R. Degner

Comments Summary It is very interesting to review the technical changes which have occurred in the industrial practice of minerals flotation over the past two decades. In 1972, worldwide industrial flotation was dominated by 'mechanical' flotation machines having an individual cell volume less than 500 cu.ft. Manufactures, such as DENVER Eqpt. Co., OUTOKUMPU, WEMCO, GALIGHER (AGITAIR), AKKER, and later DORR-OLIVER, produced flotation machines featuring a mechanical rotating impeller which served to mix pulp and air, prior to flotation, and to keep the solid ore particles in suspension. While sharing this common mechanical impeller feature, the machine design of the various manufactures differed in detail; particularly in regard to the vertical location of the impeller in the cell and the means by which flotation air was brought into contact with the pulp within the rotor mechanism. A review of the existing technical literature in 1972 would identify academic research studies, particularly at Columbia University (N. Arbiter, C, Harris ...) aimed at comparing flotation cell design concepts, of the various machine manufactures, on a hydrodynamic basis. These research studies were confined to very small, laboratory bench size, flotation machines, and the benefits of incorporating hydrodynamic considerations in the scale-up of the existing 300 cu.ft. mechanical flotation technology to larger cells was not commonly practiced industrially. Technological advances in minerals flotation, over the past two decades, have been influenced by a variety of economic factors including the increasing development of lower grade ore bodies, the attractions of producing a higher grade final concentrate, and the economy of tails retreatment to improve overall plant recovery performance, and flotation system “optimization" became increasingly important through the 1970-80 time period. The trend toward processing lower grade ores led to higher tonnage mill operations, and stimulated the development of the very large capacity mechanical flotation machine for roughing and scavenging duty. In 1972, the 500 cu.ft. size flotation machine was being pilot tested and introduced to the industrial market. Today, 1993, individual cell volumes of 1500-3000 cu.ft. are operating successfully throughout the world, and well planned plant test programs have concluded that the very large flotation machine can achieve the same metallurgical performance level of its smaller predecessor. The large flotation machine development record clearly credits the incorporation of internal cell hydrodynamic considerations in guiding the scale-up of the mechanical flotation machine to large sizes. This guidance eliminated, or reduced significantly, costly in-plant prototype machine changes which increase Dramatically with increasing flotation machine size. Early in the 1980's, at approximately the time that flotation machines in the 1500 cu.ft. class were being introduced into the market, it became evident that the availability of the very large mechanical flotation machine brought with it the need for a systematic means to "optimize" the flotation system by relating flotation cell size, row length (i.e. number of cells per row), and flotation rougher, scavenger, and cleaner system configuration to the economic objectives of the concentrators' operating management. Flotation system optimization consists of quantifying the flotation process performance using a suitable model which relates the kinetic response of the trace specie and the gangue material to the cell overflow, and produces a numerical relationship between product grade and value recovery. The computer analysis technique has proven to be an invaluable tool in determining the kinetic model coefficients which characterize a given application, and is also used to apply the resulting model to a proposed minerals beneficiation situation seeking to "optimize" the flotation system by relating metallurgical grade-recovery performance, flotation cell size, and circuit arrangement, to plant space, installation, and operating costs. It is interesting to note that these same computer based kinetic flotation analysis techniques can be easily applied to quantitatively evaluate the effect of different chemical reagent strategies, and flotation air transfer, on process performance for a variety of candidate feed ore types.

Jan 1, 1993

By F. L. Bazzanella

Cyprus Pima has two concentrators, one with a conventional crushing-grinding circuit and the other using semi-autogenous grinding followed by ball mills.

Jan 1, 1978

By Stanley Bunk

The fluidized bed was invented by Fritz Winkler of Germany in 1921. The first application in the U.S. was in the development of the fluidized bed catalytic cracking of petroleum in 1942. Today, fluid bed cracking reactors are an integral part of every oil refinery. When fluid bed technology was first considered for applications outside the petroleum industry it was recognized to have uniform temperature, close control of the gaseous atmosphere and excellent mixing between solids and gases. Roasting of sulfide ores and concentrates was an obvious match. The first application was a single stage roaster for gold refining in 1947. There have been over four hundred commercial fluid bed roasters built and operated successfully in the four decades since the fluid bed was invented. There are three general categories of roasting applications. The largest number of roasters fall into the dead roasting category which includes gold ore roasters. The other categories are sulfating roasters and partial roasters (Reference 1).

Jan 1, 1990

The use of coal as a fuel causes air, pollution in; a number of different forms, and in nearly all stages of its, handling, preparation, storage, use and-disposal of its residue. First let us consider the handling of coal. As shipped, particularly to large utilities, it is run-of-mine bituminous made up of large chunks as well as pulverized particles. Because it 'is in an open car or barge, it is subject to the action o winds and the small particles may be blown around adding to the-particulate load in the atmosphere. Mien un¬loaded from the barge or car, there is again an opportunity for the wind to blow the fine particles around. All of us I am sure have seen a barge at the dock of a utility plant being unloaded by a clamshell bucket. This, after grabbing its load from the barge, lifts it some 60 or 70 feet and, then drops it on a conveyor, which carries the coal to a storage area.

Jan 1, 1964

By R. Hagemeyer

In North America, the paper industry is by far the largest consumer of coating and filler mineral pigments. Present use is at an annual rate of 5.5 million metric tons with a value of $660 million. Current estimates are 65 percent is used in coating and 35 percent in filler applications. During the past decade, the switch to alkaline papermaking has provided the opportunity to substantially increase filler levels while maintaining paper strength. As a result filler consumption has been growing at a late in excess of 15 percent yearly. Unfortunately, within a few years, mandated recycling could slow or even reverse this trend. The critical issue is finding an economically viable method for recycling the mineral pigment and/or minimizing the disposal problem

Jan 1, 1994

By B. Anamaeric

Economic, environmental and operational disadvantages of the traditional blast furnace process has led to the development of direct smelting reduction processes, including those that utilize self reducing/ fluxing dried greenballs as iron oxide feed materials. This is mainly due to improved carbothermic reduction, carburization and reaction kinetics. In this paper, the morphological changes of the greenballs as they transform to pig iron nuggets are examined over time at a constant temperature of 1,400° C. The products produced after each treatment were characterized using optical microscopy, scanning electron microscopy/energy dispersive spectroscopy and point counting/image analysis. The changes in the percent metallized area, wustite dendrite and slag matrix content of the structures were calculated. It was determined that the transformations were initially controlled by dissolving and containment of iron oxides in the molten slag and their consequent reduction to iron, followed by coalescence of the metallized areas. The final transformations were controlled by the carburization of the metallized areas.

By L. J. Buter, D. J. Collins

Introduction FMC's Paradise Peak gold mine was discovered by staff geologists in July 1983. Located south of Gabbs, in western Nevada, the deposit contains about 11 Mt (12 million st) of ore grading at 3.6 g/t (0.105 oz per st) of gold and 129 g/t (3.75 oz per st) silver. It is estimated that the ore contains 34 t (1.1 million oz) of recoverable gold and 933 t (30 million oz) of recoverable silver. The 3.6 kt/d (4000 stpd) mill began operation April 14, 1986, just 18 months after Davy McKee completed a feasibility study and construction, and two-and-a-months ahead of schedule. It also came in about 10% under budget at a cost of about $100 million. Crushing Run-of-mine ore is delivered from the mine in 45-t (50-st) haul trucks to a 272-kt (300,000-st) capacity open air stockpile. Ore is reclaimed using 5 m3 (7 cu yd) front-end loaders that feed a 91-t (100-st) hopper equipped with a 610- x 610-mm (24- x 24-in.) grizzly. A 1.4- x 11-m (54-in. x 35-ft) apron feeder delivers ore from the hopper by way of a vibrating grizzly screen with 127 mm (5 in.) openings to a 1- x 1.3-m (43- x 51-in.) Rexnord jaw crusher. Crushed material is conveyed to a 1.8- x 4-m (6- x 14-ft) Link Belt vibrating screen equipped with a 50-mm (2-in.) manganese grizzly bar deck. Screen oversize is fed to a 1.7/0.6-m (5.5 ft) Rexnord standard cone crusher. Product from this crusher joins the -50 mm (-2 in.) screen undersize and is conveyed to a 136-t (150-st) surge bin. Three hydraulically driven belt feeders deliver ore from the ore bin to three 2 x 6 m (7 x 20 ft) Link Belt single-deck tertiary screens fitted with 6 x 25 mm (0.25 x 1 in.) slotted polyethylene screens. Screen undersize - -6 mm (-0.25 in.) rock - is conveyed to a 3.6-kt (4000-st) ore storage bin. Screen oversize is delivered by way of a conveyor to a 91-t (100-st) surge bin. From this bin, two belt feeders feed ore to two 1.7 m (66 in.) Rexnord Gyradisc crushers, which are in closed circuit with the tertiary screens. Design features include magnetic protection for tramp iron removal and sloping floors and pump sumps for ease of clean up. Dust scrubbers keep the working environment clean and in compliance with state dust emission regulations. Grinding Two 1 x 4.5 m (3.5 x 15 ft) belt feeders deliver ore from the fine ore bin to a conveyor belt that feeds it to the 5 x 7 m (16 x 22 ft) Allis-Chalmers ball mill. The conveyor belt is equipped with a Merrick weightometer. This controls feed rate to the ball mill by speed control on the hydraulic motors driving the feeders. The 2.6 MW (3500 hp) powered mill grinds 3.6 kt/a (4000 stpd) to an average grind of 85% -75 µm (-200 mesh). The mill is in closed circuit with four 660 mm (26 in.) Krebs cyclones. Three of these are normally in operation while one is a standby. Warman pumps feed the cyclones through a cyclone distribution manifold. The cyclone underflow returns to the ball mill, which has a 300% average circulating load. Mill discharge pH is 11, and that is obtained through pebble lime addition to the feed belt. Cyclone overflow is sampled using a Heath & Sherwood two-stage sampler. It then flows to a 27-m-diam (90-ft-diam) Eimco thickener. Thickener overflow is returned to the grinding circuit, while underflow at 50% solids is pumped to the leaching circuit. Grinding-circuit design features include a steeply sloped floor for ease of clean up, an open area over the pumps for maintenance accessibility, and a ball hopper with a self discharge bottom to speed ball addition. Other features include a mill liner handler and an air clutch that connects the mill motor to the mill.

Jan 12, 1986