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By Frank R. Cappuccitti

This paper will deal with current market trends for sulfide mineral collectors in three distinct parts; the global market for sulfide collectors, collectors as tools to solve mineral processing problems and new collector Research in the 1990's. The global market and manufacturing of sulfide collectors will be detailed as well as the trend towards using increasing amounts of specialty products. The use of Total Quality Concepts for laboratory and plant evaluations of new products will also be discussed. Research in the 1990's for sulfide collectors will need to focus not on the development of new chemical species but on the application of the new technologies that have already been developed.

Jan 1, 1994

By Hugh Boyd

Jet pulverization is a relatively new tool for fine grinding. It is not yet in general use in the mining and ore dressing fields, since most of the requirements in these areas have been for relatively coarse particle sizes. As the need for finer grinding increases - because of different ores, new products, and new values being sought - jet pulverization will, increasingly, be properly used.

Jan 1, 1969

By Paul C. Schmall, Arthur B. Corwin, Hugh S. Lacy, Derek Maishman

For reasons of hydraulic design and constructability, water supply tunnel systems are often located relatively deep, in competent rock. Where the rock lies below a thick cover of water bearing soils, artificial ground freezing offers a low risk, cost-effective method of constructing access shafts. Several examples, in Kansas City, MO and in Brooklyn and Queens, NY, illustrate the use of freezing to provide structural support and ground water exclusion. In the case histories presented, the shafts range from 6m to 12m (20 to 40 ft) in diameter and soils vary from clays to boulder beds with depths in excess of 73m (240 ft) to competent bedrock. Where tunnels for infrastructure are designed to be driven in rock, vertical access may encounter a considerable thickness of overburden soils with groundwater. In such cases, shaft sinking problems are analogous to those confronted by mining engineers over 100 years ago. At that time, newly developed refrigeration machines were set to freeze the ground water and stabilize running sands. Although modern technology has refined our efforts, the basic features of the ground freezing to be described here are the same as those used in the last century. Vertical holes drilled on a circle surrounding the shaft site are equipped with leak-free steelpipes through which a refrigerated brine is circulated. In this manner, a frozen cylinder, seated in rock, is formed when the earth freezes between adjacent pipes. Shaft excavations take place inside a self-supporting, ground-water excluding structure. For mines, no better method of sinking production shafts through deepwater-bearing ground has yet been established. Indeed, major deposits of coal, potash, and salt would have remained inaccessible to this day were it not for the continued use of artificial ground freezing. If mine shaft freezing became relatively commonplace, early applications to civil engineering were few. Mussche and Waddington (1946) mention only five projects between 1892 and 1935; three of these relate to subway or vehicular tunnels in Paris, Antwerp, and (the most extensive) at five locations of the Moscow Metropolitan Railway development. In the United States, the method was used to spectacular effect in 1936, freezing about 3,000 cubic yards of silt to stop a slide

Jan 1, 1999

By G. Whitney, J. Steiner

Introduction The Summitville Mine located in southwestern Colorado is an example of the potential impact that natural weathering and mining activities can have on environmental quality. Acid rock drainage and metals leaching from active and historic mine districts are a major environmental problem facing the mining industry today. Sulfide ore exposed naturally or during mining operations has the potential to produce leachates that contain high concentrations of dissolved metals. These leachates can affect the quality of plant and animal health in surface water used for agriculture, recreation and human consumption. Pintail Systems has developed biological processes for detoxification of cyanide in heap-leached spent ore and process solutions. During application of spent ore cyanide bio-detox processes we have also observed a substantial reduction in many of the leachable metals in biotreatment solutions. These field observations of soluble metal reduction led us to propose that metal bio-mineralization should be a secondary treatment goal of spent ore detox in Focused Feasibility Studies (FFS) for the Summitville Mine. In the FFS (described in a companion paper) for Summitville, spent ore from the heap leach pile (HLP) was loaded into PVC test columns (six inch X ten foot) and was leached with bacteria/nutrient solutions. Two treatment designs were studied: a standard percolation leach (aerobic) and a saturated leach design where the ore was saturated with the heap leach solution to which bacteria and nutrients were applied in a continuous biotreat leach. The bacteria for all column treatment tests were isolated from the spent ore at depth through the Heap Leach Pile (HLP) in the saturated and unsaturated zones. Bacteria isolated from the heap material were tested for cyanide oxidation capacity and were submitted to a bioaugmentation program to improve reaction kinetics and metals tolerance. The final treatment population consisted of several distinct species including aerobic heterotrophs, facultative anaerobes and sulfate-reducing bacteria. The remineralization of soluble metals was observed through a decrease in copper in column leachate solutions and the formation of observable mineral products on ore surfaces in the columns. Several of the tests were run in clear PVC columns to facilitate observation of mineral formation. The column ore contents were photographed before, during and after the biotreatment process which ranged from 10 to 20 days for each test column. Ores were collected from each column after the treatment was complete and were submitted for SEM and TEM study at two laboratories - the USGS SEM Laboratory in Denver, Colorado and the City College of New York SEM laboratory. Treatment Process Description Numerous species of bacteria, fungi and yeasts are capable of accumulating many times their weight in soluble metals. Both living and dead biomass are effective in removing soluble metals from waste streams containing gold, silver, chromium, cadmium, copper, lead, zinc, cobalt and others. Soluble metals may also be immobilized in soils by natural or engineered biomineralization reactions. Several commercial processes using biological reactions are being applied on an industrial scale for metal remediation. Bacteria found in natural and extreme environments have developed a wide variety of metabolic functions to adapt to these environments. These natural microbial functions contribute to global mineral cycling that continuously forms, transforms and degrades minerals and metals in the environment. Biomineralization is described as a surface process associated with microorganism cell walls where the remineralization occurs. The biogeochemical activities initiated by microorganisms in ores, soils, surface and groundwater environments can dominate the formation and transformation of those mineral environments.

Jan 1, 1995

By K. Kuhnhenn, G. Prommersberger

General aspects In Germany, swelling rock is mostly found in the keuper formation. Keuper is a sedimentary rock formation of varying composition. It mostly consists of fine or medium layers of clay/silt/marl/dolomite stone with intercalations of gypsum or anhydrite in strips or nodes. After disintegration of the top layers and tectonical incidents, the gypsum level, i.e. the upper [ ]

Jan 1, 1989

By M. C. Fuerstenau

Flotation data indicate that sulfonate and dodecylamine adsorb physically on Mn02 at ambient temperature. Oleate also adsorbs physically if the zero-point-of-charge of the Mn02 is sufficiently high. Chemisorption of oleate apparently occurs between pH 8 and 9, and this phenomenon is enhanced considerably at elevated temperature.

Jan 1, 1966

Sweden is beginning to reap the rewards of a process that has transformed a country with a history of metal mining into one of Europe's most vibrant exploration regions. Exploration and mining companies from North America, Europe and Australia have joined local firms in the search of gold, base metals and diamonds. This has been due to changes in Sweden's mining laws in the early 1990s. These changes opened the way for unhindered private sector investment in the country's mineral industry. More than 20,000 km2 (4.9 million acres), mainly in northern Sweden, is now held under granted or applied exploration claims. Exploration permits diamonds, applied or granted covers more than half of Sweden's surface. This is a greater proportion of the country than ever before. Major mining companies and junior explorationists are evaluating a geological potential that bears favorable comparison to other major mining centers. Historically, Sweden's gold re- sources occur in greenstone belts in northernmost Sweden and in association with massive sulfide deposits in the Skellefte district. These are receiving particular attention by exploration companies. In addition, new areas in Sweden are also being explored for gold. This increases the probability that Swedish gold production - already the highest in Europe - will increase in the future (Table 1). Sweden's recorded mining history goes back for much of the last large pool of expertise in exploration, mining, equipment manufacturing and minerals industry research. In addition, the Geological Survey of Sweden provides sup- port for exploration in terms of data archives, processing and publications. Other benefits for exploration companies are Sweden's communications infrastructure, its member- ship in the European Union, bringing access to one of the world's major markets and the high level of educational, technical and language skills held by the country's work- force. And deregulation of the economy and the introduction of competitive corporate tax rates have made Sweden a favorable destination for investment in Europe.

Jan 1, 1997

By Lennart Mukka

LKAB has been mining iron ore in northern Sweden for about 100 years and now enters the next century with a major new investment in Kiruna. The under- ground projects involve construction of a new main haulage level, a new mining system and a new ventilation system. This paper describes the Ventilation Procject from the investigation stage through to construction.

Jan 1, 1995

By John W. Rushton

Maintenance and inventory are usually the last items considered in mine development. They need to be addressed properly and early. The micro-computer brings sophistication within the reach of even the smallest mines. Maintenance and inventory programs, if properly installed, will reduce costs 15 to 25% and allow management time to address the mining and metallurgical problems at start up. Shops and warehouses are rarely designed properly. Large engineering firms spend 5 to 20 times more than is necessary for first class facilities. There is an optimum design, size, and layout. Take the time necessary to assure you get the right people, programs, and facilities in that order. Maintenance, inventory, and inventory control must be addressed early if a small mine is to have a chance at optimizing costs during the first two years of operation. This is hard work and is usually put on the back burner until the mine is in some degree of trouble. Hiring an experienced maintenance superintendent is important but it is not the complete solution. Maintenance systems, design of facilities, and use of computers are not skills that maintenance people usually have. In addition, the work of ordering spare parts and working with erection people is a full time job and any maintenance people on site during construction are quickly recruited. The end result is that few mines start up with an adequate Maintenance or Inventory System in place. The months, and in some cases years, that the mine attempts to operate without a system are both painful and expensive. Designs of successful integrated maintenance and inventory programs are virtually 100% supported with some outside assistance. Our system is the approach that we are most familiar with and this paper will isolate how Rushton International would go about setting up systems and designing support facilities. Micro-computers are the only way for a small mine to go. ~ini-computers cost more originally and operating costs are many times higher than even the most sophisticated micro system. Micro- computer software is developed further and recent advances in hardware makes medium priced units equal to most mini's in RAW COMPUTER POWER. Mines in general, and especially small mines, have no need for main frame power. MAINTENANCE A good maintenance program has: 1. Equipment Master List a. Equipment Detail Reports 2. Work Order and Backlog Control Program 3. Component Control Program 4. Tire Program 5. Wear Materials Program 6. PM Control Program 7. Maintenance History Program 8. Performance Program We also track miscellaneous items such as MSHA training and inspections, timekeeping, etc. Rather than going through the program step-by-step, it makes more sense to go through a typical Maintenance Day and show how the programs are used. The first thing maintenance supervision needs to know is "how we are doing." We

Jan 1, 1987

By M. S. Kabibwa, E. K. C. Chanda

In planning for the future, Nkana Division deepened the Mindola sub-vertical shaft which was commissioned in 1994 in order to access the 30 Mt of ore between 1274 and 1570 m levels. The Nkana Synclinorium which is estimated to contain 250 Mt of ore is being accessed from the vicinity of Central Shaft. These areas are being planned with the intention of maximizing the use of computers in geological modelling and mine design so as to overcome the inadequacies of manual planning techniques. As a result, there is an increased demand for quality output from the computerized mine planning system the division has been developing over the last few years. A new workstation comprising the Hewlett Packard HP 71 51100 MHz and a CRX graphics monitor was acquired in 1995 together with the LYNX (version 3.09 and version 4.0) Mine Modelling System. Currently the workstation is being used for geological modelling and mine design for the Zerofold at Central Shaft and the Mindola mining at depth project. AutoCAD and Mine Works Planner have been added to the sys- tem configuration. Mine Works Planner is likely to replace Lo- tus123 for mine scheduling tasks. Computer applications in the area of mine planning at Nkana has led to considerable time savings and improved efficiency in areas formerly performed manually and has allowed speedy processing of data that would otherwise have proved too time consuming. Nevertheless, a lot of work still needs to be done in the areas of geostatistics, stope design and financial modelling of mining options. For the foreseeable future computer based planning will operate parallel to manual methods until such a time as sufficient personnel are proficient in the use of computer systems. This paper describes the program of computerization at Nkana Division, reviews current applications and the benefits and experience gained and discusses the promise of current and future developments.

Jan 1, 1996

By Kurt Burg, Allen Reicks

Tapered clamping devices have been used successfully over the years to transmit torque and bending loads from conveyor drives to conveyor belts. Proper design and application is important in the successful operation of these key components. This paper includes a historical review of component design and application and an overview of the important dynamics and limiting factors. Actual applications and simulation models are used to demonstrate the correct use of these devices.

Jan 1, 2002

By Mona M. Fawzy, Ahmed A. Eliwa, Ebrahim A. Gawad, Ahmed H. Orabi, Amal E. Mubark

The growing demand for rare earth elements (REEs) has led to numerous recent studies to recover these elements from various bearing ores and wastes. Therefore, the recovery of REEs from Ras Baroud polymetallic concentrate has been investigated in the current study. Physical beneficiation for the Ras Baroud pegmatite sample was carried out, yielding a concentrate for euxenite (Y), fergusonite (Y), xenotime (Y), monazite (Ce), allanite, thorite, uranothorite and Hf-zircon, which resulted in raising the concentrations of REEs, Th, Zr, U and Ti in the sample. Fusion digestion processes with sodium hydroxide were studied using the conceived predictive diagonal (CPD) technique. The three experimental digestion groups proved the dissolution of 99.9, 95.6, 99.9, 52.5 and 0.47 percent for REEs, Th, U, Ti and Zr, respectively, under fusion conditions of 723 K, 120 min, 1/1.5 ore-to-alkali ratio, and smaller than 100-μm particle sizes. Fusion kinetics, isotherms and thermodynamics were investigated using several suggested models, namely, pseudo reversible first order, uptake general model and shrinking core model, which matched well with the experimental digestion results. Selective recovery of actinide content from the REE content of the digested concentrate chloride solutions was accomplished using solvent extraction with di-2-ethyl hexyl phosphoric acid. About 99.9, 99.9 and 4.2 percent extraction efficiencies for Th, U and REEs were realized, respectively, using 0.3 mol/L solvent concentration in kerosene as a diluent, 1/2 organic-to-aqueous ratio, aqueous pH of 0.2 and contact time of 15 min. Thorium and uranium ions were stripped with 2.5 mol/L sulfuric acid solution with 94 and 98 percent stripping efficiency, respectively. A highly purified REE precipitate was obtained from the raffinate solutions. Zircon mineralization tailings were obtained as a byproduct through the alkaline digestion process.

Oct 1, 2024

By J. G. Groppo, B. K. Parekh

Removal of moisture from fine (minus 28 mesh) dean coal to 20 percent or lower level is difficult using the conventional vacuum dewatering technique. High pressure filtration technique provides an avenue for obtaining low moisture in fine clean coal. This paper describes a couple of novel approaches for dewatering of fine clean coal using pressure filtration which provides much lower moisture in fine clean coal than that obtained using conventional pressure filter. The approaches involve (a) split stream dewatering and (b) addition of paper pulp to the coal slurry. For Pittsburgh No. 8 coal slurry, split stream dewatering at 400 mesh provided filter cake containing 12.9 percent moisture compared to 24.9 percent obtained on the feed material. The addition of paper pulp to the slurry provided filter cake containing about 17 percent moisture.

Jan 1, 1995

By A. Mahtab, S. Xu, P. Grasso, B. J. Fu

The large population base, complex geology of the large land mass, and notable commercial activity have accelerated the development of underground construction market in China. The projected lengths of underground openings per year in the various sectors are: hydro-tunnels, 180 km; coal mine entries, 40 km; transport-tunnels, 300+ km. An example of the mega projects (being planned by the Government) is the water supply scheme for connecting Yangtze river to Yellow river involving 131 km of water tunnels with a diameter of 8-10m. Several large projects are highlighted in the paper with reference to the schemes for generating hydro-power, mining of coal and minerals, and constructing transportation networks. The related problems of construction and geomechanics are outlined.

Jan 1, 1995

By G. C. Kachel

During the past two years, there has been an increasing acceptance of process automation among ferrous, non-ferrous and non-metallic rock processing operations in an attempt to keep total unit costs in line in a market situation where labor and material costs are rising almost daily. Previous technical papers (1) (2) (3) (4) (5) have described, in considerable detail, instrumentation and automatic control devices that have been successfully applied in a wide variety of crushing and grinding facilities. While many of the basic control philosophies that evolved almost ten years ago remain essentially unchanged, new components and devices have been developed during the past two years that permit these philosophies to be better implemented in operating plants. Some of these devices and their application will be discussed with particular emphasis placed in describing the basic control philosophy employed as well as some of the hardware or components comprising typical crushing and grinding circuit control systems. Before any instrumentation or automatic control system can be successfully devised for a specific facility, there must be a clear understanding and agreement by supplier and user as to the control system objective. In the case of a crusher feed rate control system, the objective is generally to maximize thru-put of a given finished product size. While this is often the case in a grinding circuit automatic control system, the reasons may be entirely different. Taconite processors whose end product is to be pelletized, generally attempt to control their grind within narrow limits to optimize balling action. Other milling operations are more concerned with obtaining metallurgical liberation and can, in many cases, tolerate wider swings in finished grind.

Jan 1, 1969

By B. S. Treiber, R. A. Lohnes, S. M. Levorson

As part of a research program to develop a coal-handleability index that would predict the ease with which a coal would flow through a handling system, an apparatus was developed to directly measure the unconfined Yield strength and bulk density of consolidated-coal samples. The new test apparatus provides a fast and simple method for determining the strength and compressibility parameters that are associated with the handling characteristics of crushed coal. Comparative tests were conducted using a low-stress triaxial-test apparatus. To check the accuracy of the new method, four coals with a variety of moisture contents and gradations were tested using the new method. These tests indicate that the new test device yields valid results. Further, the speed and ease of operation of the new device makes it suitable for quality control and quality assurance in plants.

Jan 1, 1996

By Donn A. Calder, Wayne C. Henderson

The Calmet Process for extraction and recovery of gold and silver from concentrates and high:grade ores has been a commercial reality for over two years. During that time period, almost seventy-five different concentrate (or ore) types have been processed in approximately 200 separate lots (a total of almost 2000 short tons). During commercial operation of the process at the plant in Fountain, Colorado, recovery of gold and silver into <lore' has averaged almost 93% for gold (range 81-98%) and over 90% for silver (range 76-97%) based on a fire assay target and calculated head values.

Jan 1, 1998

By J. L. Huiatt, D. G. Foot, J. D. McKay

The US Bureau of Mines compared column flotation using either fine or coarse bubbles with conventional flotation on a Montana chromite ore. On deslimed ore, fine-bubble column flotation produced a &.7% Cr2O3-grade rougher concentrate with 87% recovery, compared with 43.8% and 43.5% Cr2O3-grade rougher concentrates with 85% and 77% recovery for coarse-bubble column flotation and conventional flotation, respectively. On undeslimed ore, coarse- and fine-bubble column flotation produced rougher concentrates containing approximately 41.5% Cr2O3 with 95% recovery, exceeding conventional flotation, which produced 35.6% Cr2O3 -grade concentrates with 87% recovery.

Jan 1, 1987

By A. E. Isaacson, D. B. Dreisinger, G. A. Kordosky

The U.S. Bureau of Mines is researching the application of solvent extraction technology to highly acidic (pH < 1) copper leach liquors. As increasingly complex copper ores are mined for leaching, use of highly acidic leach solutions maybe necessary to effectively recover the contained metal values. A mixture of two commercially available extractants, based on aldoximes and substituted 8-hydroxyquinoline, which has a high transfer efficiency has been identified. A synthetic leach liquor, containing 5 g/L Cu at pH 0.9 was processed utilizing the mixed extractant and a laboratory SX circuit. The loaded organic was stripped with a synthetic barren electrolyte compatible with electrowinning technology.

Jan 1, 1993

By D. Hong, K. N. Han

The leaching behavior of rhenium in ammonium iodide solutions with iodine as oxidant was studied. Experiments were carried out in an autoclave to investigate the effects of stirring speed, temperature, solution pH, and iodine and iodide concentrations on the dissolution of rhenium. It was found that a high temperature and a high solution pH were essential for the efficient leaching of rhenium. The dissolution rate was found to be dependent upon the concentration of iodine and iodide. It was concluded that the dissolution of rhenium under the conditions studied was controlled by the mass transfer of iodine with an apparent activation energy of 15.8 kJ/mole.

Jan 1, 1999