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Laboratory testing by the Federal Bureau of Mines has shown that the removal of insoluble slimes using selective flocculation and flotation is a viable method for treating low-grade potash ores which have a high content of water-insoluble impurities. Results indicated that up to 85 percent of the insoluble slimes could be removed from sylvinite ore containing 5 percent water insolubles and 13 percent K20 using nonionic or cationic polyacrylamide flocculants and cationic, anionic, and/or nonionic collectors. Subsequent potash flotation recovered up to 88 percent of the potash in rougher concentrates containing 47 to 57 percent K20. Sizing and cleaner flotation of the rougher concentrates upgraded the products to 60 percent K20. Filtration of the insoluble slimes flotation concentrates recovered 87 to 0 percent of the brine. Flotation concentrate filtration rates were 7 times faster than the filtration rates of mechanically deslimed products.

Jan 1, 1977

By J. B. Clemmer

PRODUCTION of magnesium metal in the United States during the past decade has increased from less than 600,000 lb. in 1928 to more than 4,800,000 lb. in 1938.1 The growing industry has stimulated interest in methods of production and in sources of raw material. All of the present domestic production is from brines. However, the availability of large tonnages of magnesite in the state of Washington, together with the possibility of cheap power, have created interest in the utilization of magnesite for the production of magnesium metal as well as for other purposes. Magnesite, the carbonate of magnesium (MgC03), usually is associated with lime-stone (CaCO3) and dolomite (MgC03 CaCO3). It occurs in crystalline and microcrystalline (sometimes termed amor-phous) forms.2 The more common crystal-line mineral is found in various shades of white, gray, yellow and brown, the colors being due to impurities, chiefly iron. Magnesite has a hardness of 3.5 to 4.5 and a specific gravity of 3.0 to 3.1. It forms rhombohedral crystals in the hexagonal system, having a vitreous, pearly luster. The quarries and mines of the Northwest Magnesite Co. near Chewelah, Wash., are large producers of magnesite for refractories.

Jan 1, 1940

By Zhong g. Shui-ping

A new type Pb-Ag (0.8wt%)-Bi (0~5.0wt %) alloy used as anode in electrowinning of zinc from sulphuric acid electrolytes was prepared. The electrochemical properties of this ternary lead alloys have been tested and compared with those of Pb-Ag (0.8wt %) anodes used in industry. Results show the anodic overpotential decreases with the increasing of Bi content in the alloys. When the content of Bi was 1.0 wt% and 5.0 wt%, the anodic overpotential is about 40?50 mV and 60?80 mV lower than that of Pb-Ag (0.8wt %) alloy, respectively. The formation of oxide layers on the surface of these alloys was traced by LSV methods and the composition of the anodic oxide layers was characterized by XRD and SEM analysis. The surface layer on the two type anodes examined is mainly composed of a?PbO2 and ß?PbO2. But different structure of the surface layer was observed, Pb-Ag (0.8wt%)-Bi (1.0wt %) has a more fine-grained structure as compared to Pb-Ag (0.8wt %). But the film on Pb-Ag (0.8wt%)-Bi (3.0wt %) alloy is rather friable, cracked and not tightly attached to the anode.

Jan 1, 2008

By Oxenford R. J

An important rutile-ilmenite-zircon bearing sand deposit was discovered by local farmers at Eneabba, 300 km by road north of Perth in 1970. These heavy minerals occur in a series of ancient strandlines and associated dunal deposits at elevations from 85 m to 170 m above the present sea level and are situated,30 km inland. The strandlines were deposited on wave- cut platforms in an ancient bay bounded by Mesozoic sediments during a series of regress- ions from a high sea level, probably during late Tertiary or early Pleistocene times. The immediate source of the heavy minerals in the Eneabba deposit is a widespread low content of those minerals in the nearby Mesozoic sedi- ments. The high-grade southern portion of the Eneabba deposit has been closely drilled and is now being prepared for production by Allied Eneabba.Pty. Ltd., a subsidiary of Allied Minerals N.L. This part of the deposit is 11 km long and up to 2.5 km wide. It is characterised by little or no overburden and the average depth of mineralisation, bounded by a 2.5 per cent heavy mineral cut-off, is 12 m. The water-laid strandline deposits at the base of the mineralisation are generally high grade, ranging from 20 to 60 per cent

Jan 1, 1973

By Y. H. Wang

Micro-flotation tests of spodumene, beryl, quartz and feldspar have been carried out by using CaCl2 and FeCl3 as modifiers and a blending collector of oleic acid and hydroximic acid. CaCl2 shows efficient activation for spodumene when pH is above 11.5, and FeCl3 exhibits a markedly activation and good selectivity for spodumene in the range of pH 4 to 10. The main species of CaCl2 are CaOH+ and Ca(OH)2 when pH is above 11.5, and the main species of FeCl3?6H2O are Fe(OH)+2 and Fe(OH)3 during the pH range of 4 to 10. A selective flotation of spodumene and beryl from pegmatic ore had also been completed while using FeCl3?6H2O as activator and the blending collector. A bulk concentrate containing 1.087% BeO and 4.70% Li2O has also been obtained in the flotation of spodumene and beryl from pegmatic ore assaying 0.097% BeO and 0.45% Li2O, and the recoveries of BeO and Li2O in concentrate are 74.38% and 69.50% respectively.

Jan 1, 2014

By Elliot Rexford

The quality of aggregate materials is of major importance in governing durability and permanence of concrete structures. The problem of selecting suitable aggregate materials is two-fold. Geological factors include the type and character of the aggregate source, presence of known or suspected reactive constituents, and presence of thermally incompatible materials. Laboratory investigations include petrographic studies, soundness and reactivity tests, and tests of thermal properties. The importance of each factor in the selection of satisfactory aggregate material is considered in detail.

Jan 3, 1950

By Y. Ye, J. D. Miller, E. Pacquet, S. Gopalakrishnan

From laboratory research activities during the past five years, it is now evident that effective flotation separations can be achieved with the high-capacity air-sparged hydrocyclone. The effectiveness of the equipment has been demonstrated on a pilot-scale basis (1 tph) for a number of mineral commodities including coal, copper, gold, and industrial minerals using a nominal 5-cm x 50-cm system with separation efficiencies equivalent to those achieved by conventional flotation machines. The high specific capacity of the air-sparged hydrocyclone (100 to 600 tpd per cubic foot of cell volume for a nominal 5 cm x 50 cm system compared to 1 to 2 tpd per cubic foot of cell volume for conventional columns and mechanical machines) makes it especially well-suited for the pro- cessing of low-grade ore. As a result of these pilot-scale successes, a number of plant-scale test programs are planned for larger-diameter units to establish wear characteristics and scale-up relationships for design purposes. The status of the air-sparged hydrocyclone technology is reviewed in the present paper, including a description of the system, fundamental considerations of flotation mechanisms, general discussion regarding the effect of control variables, and the significance of feed characteristics.

Jan 1, 1988

Semiautogenous (SAG) ball mills are being increasingly used today for the coarse grinding of a range of ores, including gold, copper and iron. Larger mines are demanding mills with larger throughputs. This has led to some remarkable developments in mill diameters and installed powers. Conventional design principles - mills with trunnion bearings - have reached their limitations. This article describes one SAG mill with a slide-shoe arrangement and Krupp Polysius' Combiflex twin drive. In August 1997, the world's largest SAG mill with a slide-shoe arrangement was commissioned in Queensland, Australia, operating as a wet mill. The inside diameter is 10.4 x 5.1 m (34 x 17 ft) effective grinding length. The 1.36-ktlh (1,500-stph) SAG mill is driven by two Combiflex drives (twin drives with 2 x 5,500-MW or 7,375-hp installed motor power) in conjunction with a girth gear (outside diameter 11,890 mm or 468 in.). Commissioning of the SAG mill was completed with no notable technical difficulties. The plant runs continuously except for planned maintenance stoppages and process-specific reasons. As this article is written, the machine has been in operation for about 8,000 hours without major problems.

Jan 1, 1998

By J. C. M. De Souza

The Samarco pipeline, the longest in the world for iron ore slurry transportation, started operation in 1977 to transport concentrate from the Germano facilities, in the state of Minas Gerais, to the pelletizing plant, located 396 km away, in the state of Espirito Santo, on the south-east coast of Brazil. Designed for a nominal capacity of 12 million tons per year, the pipeline reached 15.5 million/year due to operational improvement and, in late 2005, it was resized to transport 16.5 million tons per year, with the installation of a booster station. In order to ensure the accurate performance of the system, a pipeline cleaning programme was carried out and, since it has been 29 years from the operation start-up, precise knowledge of the pipe condition would be fundamental to guarantee the success of the project. The cleaning programme demonstrated the potential of operational gains from this initiative, and its effect on the corrosion control and future measures, which should be permanently adopted to maintain the improved capacity. The intelligent pig runs provided essential data used to establish a pipeline integrity programme that allowed Samarco to develop a pipe repair plan based on the severity and significance of the features and to implement a future pipe replacement plan.

Jan 1, 2007

By James M. Riddle

INTRODUCTION Block-caving mines are generally large operations. Calculating the quantity and value of mineral present and determining the economic limits to mining are complicated processes requiring much time and effort. If these processes are to be worthwhile, they must be accurate and reliable. Success in planning may increase the economic returns significantly. Since capital investments in block-caving mines are generally quite large, and development may span several years, quicker and more accurate methods of mine layout are very worthwhile to the mining industry. The purpose of this study is to develop an approach to the evaluation and layout of block-caving mines. The study included development of a simple approach to modelling ore reserves and a rapid, dynamic programming solution for optimum ultimate mining limits. TRADITIONAL APPROACHES TO BLOCK-CAVING MINE LAYOUT General discussion of techniques of calculating and valuing ore reserves can be found in the literature, (1-4). Mining limit approaches have been investigated by many and follow five general methods: 1, Moving cone method (5) 2. Graphroriented technique (6,7) 3. Dynamic programming technique (7,8,9) 4. Network flow method (10,11) 5. Pillar method (12) Of these investigations, only two were developed for underground mining applications, those of Sharp (9) and Riddle (11).

Jan 1, 1977

By Harold G. Moulton

IT is highly significant that engineers should seriously consider the interrelations of technology, economics, and government. It is indicative of the emergence of maladjustments and problems that perplex our thinking and frustrate our activities. Instead of a world in which scientific discoveries and their applications through engineering to the processes of wealth production are regarded as the royal road to progress, we now find science and engineering being made responsible, in no small degree, for our economic and social troubles; and the powers of government are even being invoked to stem the tidal wave of technology. Indeed, there is a deep-seated fear, manifested in the writings of some of our greatest scientists as well as in popular discussions, that science may destroy our civilization.

Jan 1, 1938

By C. J. Myers, D. L. McKinnon, A. A. Dasys

In 1988, the National Institute of Occupational Health and Safety (NIOSH) published an information bulletin stating that whole diesel exhaust should be considered a probable carcinogen. Since then, regulations across Canada and the United States (Mine Safety and Health Administration, MSHA) have looked at appropriate exposure limits for underground mine workers. In Canada, an interim standard of 1.5 mg/m3 Respirable Combustible Dust (RCD) has been adopted by some provinces and is being looked at by others. MSHA is considering levels as low as 0.5 mg/m3 soot. Golden Giant, being aware of regulatory developments, decided to look at means of reducing diesel particulate on thier large production machinery. This machinery (LHDs and haulage trucks) is powered by Detroit Diesel 71N Series engines and is used to produce 3000 tonnes of ore/day with a longhole mining technique. Having looked at the various control technologies, it was decided to evaluate the potential of using diesel particulate filters with a copper-based fuel additive for regeneration (the process by which collected particulate is burned off). This paper outlines the control technology used and the results of the field evaluation indicating the benefits to the underground mine worker.

Jan 1, 1993

By Matsuhisa Y, Sakurai W, Shimazaki H, Peiming H, Fukahori Y

Oxygen and carbon isotope mapping of hydrothermally altered wall rocks was applied to the blind ore prospecting of skam Pb-Zn deposits in the Kamioka mining district, central Japan, where the wall rocks consist of heterogeneous rock units. The results (8180sMow of -1.1 to +17.3%o and 613CPDB of -5.0 to +4.8%o for limestones, and 8180SMOW of -0.8 to +12.5%c for silicate rocks) show isotope zonations of the wall rocks with depletions in heavy isotopes (180 and 13C) toward the center of mineralization. The isotope zonations likely formed by interaction of migrating thermal waters with the wall rocks during the mineralization. The heavy-isotope depleted zone, which indicates higher temperature or higher water-to- rock ratio of the system, occurs in the footwall of a fault, indicating that the fault played the role of main conduit of the ore-forming fluids. A heavy-isotope depleted zone was also found in an area, where significant mineralization had yet to be identified. Recent drilling in this area has intercepted a zone with a grade of 16.0% Zn, 0.8% Pb, and 35g Ag per metric tonne at a depth of about 360m.

Jan 1, 1995

By Y. J. Wang

The definitions of system pressure loss (mine head) and system resistance, which are traditionally associated with single-fan net- works, are applied to multiple-fan ventilation networks. The system characteristics -- relations among air power, pressure loss, air quantity and resistance -- are analyzed by introducing the concept of subsystems. These subsystems are associated with the fans located in a cutset of the network. For a multiple-fan network, the resistances for the subsystems and total system are dependent on the quantity ratios of the subsystems. In general the pressure loss of a subsystem or a total system does not vary as the square of the corresponding air quantity. If the quantity ratios of subsystems are all held constant, then the resistances become constant and the pressure losses are predictable from the quantities employing the "square law." The system resistance has a minimum value under the natural- splitting flow pattern. Being independent of the value of system quantity, the minimum system resistance provides a basis for comparing the different networks.

Jan 1, 1983

Flue gases from electrical power station boilers, roasting, metallurgical and chemical plants could be treated by flotation using conventional flotation machines. The flue gases are introduced into the pulp instead of the air. The flotation media is a suspension of Ca(OH)2 or CaCO3 or a solution of NH4OH etc containing Na oleate as collector and frother. The SO2 and dust content of the initial flue gases were experimentally reduced by 100 to 1000 times in one flotation operation. The velocity of the flue gases through flotation machines could reach approximatively 0.4 to 0.5 m/s and more against 1.5 m/s reached in scrubber absorbers used for this purpose, but the quality of purification is expected to be better for flotation, which is essential for the cases of heavy polluted metallurgical and chemical flue gases. For some chemical plants the flue gases flotation media may be different and more suitable as compared to the above mentioned media. The proposed flotation method could be used for separation of dry grinded ores in the form of aerosols, with a realisation of flotation from a closed space (gas bubble in the pulp) onto the interface liquid-air where the particles are attached inside the bubbles.

Jan 1, 1993

Traditionally within the mining industry, single models for both grade and geology of orebodies are created upon which all mine development decisions are based. These models provide a single interpretation of the extent and continuity of the mineralization envelope based on solids and sections interpreted from relatively wide spaced drilling i.e. the models infer behaviour of grade and geology at smaller/local scales based on data available at wider scales. The variable behaviour of grade and geology cannot be derived from single kriged resource models. In recognition of this, Newmont Mining Corporation typically uses Sequential Gaussian Simulation (SGS) to quantify grade variability and to determine its effect on some of these mine development decisions. In most of these studies the mineralized envelope remains fixed and grade simulations are generated within a fixed volume. To account for uncertainty in the geology/ mineralization envelope Newmont Mining Corporation has been experimenting with Multiple Point Statistics (MPS). Multiple-Point Statistics is an emerging technique, which can be used to generate multiple, geologically realistic, realizations of data that displays complex non-linear features. MPS uses a conceptual model of the geology, called a Training Image (TI), to infer these high-order spatial relationships. The multiple realizations allow for an assessment of the geologic uncertainty, which can be further combined with grade simulations to generate a more complete picture of the true uncertainty of a mineral deposit.

Jan 1, 2011

By G. Heinrichs

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

Jan 1, 1996

By F. Gray

Diamond tool fabricators expect strong growth in most applications for 1995 and 1996. Overall growth projects range from 8% to 10%. Diamond grinding is forecast to grow between 5% and 8%, while cubic boron nitride grinding should grow between 10% and 12%. A strong automotive industry is a major factor in this projected growth, as is continuing demand for other durables

Jan 1, 1995

By Linge H. G

The effect of sodium pyrophosphate and several polyacrylate deflocculants (Freevis 502, 528, 529 and 532; and Maxfloc 1015) on the gold loading on Calgon GRC22 and Norit R035l5 carbons was tested and found to be insignificant in a pulp free enviroument. These deflocculants can therefore be used in plants processing viscous gold pulps without fear of fouling the carbon.

Jan 1, 1990

By I. M. Ritchie

Cyanide owes its great success as a lixivant for gold to the great strength of the Au-CN bond. A replacement for cyanide must similarly be a strong complexant for gold (I) or gold (III). The various alternatives are briefly considered and it is concluded that only thiosulfate has a reasonable chance of replacing cyanide as a relatively non-toxic lixivant at the present time. However, there are considerable technical problems to be overcome before thiosulfate can be considered to be a realistic alternative to cyanide. Firstly, the leaching of gold using aerated ammoniacal thiosulfate with copper as a catalyst is a complex process which needs to be understood and controlled carefully in order to achieve maximum recoveries with minimum reagent losses. Secondly, there needs to be an option similar to the CIP process for recovering and concentrating the dissolved gold thiosulfate complex from pulps produced in the processing of low grade gold ores. The prospects for overcoming these technical' challenges are evaluated and discussed.

Jan 1, 1998