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By J. D. Miller

Certain bituminous coals of recent geological age are known to contain a significant quantity of natural (fossil or subfossil) resin. Such resinous coals are found in the western U.S., particularly the Wasatch Plateau coal field in Utah. Some of the seams in this field contain approximately 5% resin which has been recovered by gravity and/or flotation processes since 1929. Resin concentrates thus produced are of low quality and are usually refined by solvent extraction and precipitation. The purified resins are of commercial importance, being used in the adhesive, varnish, enamel and ink industries, etc: Recently, an improved flotation technique has been developed which involves ozone conditioning to selectively float resin from such coals. In this flotation process, a concentrate product which contains 95% resin at a recovery of 80% can be obtained in a single stage from coal containing approximately 10% resin, whereas conventional flotation at a similar level of recovery produces a concentrate having a resin content of 30-40%. Economic analysis shows that the ozone flotation process has good potential for use by industry.

Jan 1, 1988

By Joel L. Morrison

Wet bituminous coal fines from active and abandoned slurry impoundments are currently being examined as a recoverable feedstock for the production of coal water slurry fuel (CWSF). Preliminary analysis indicates that these coal fines can be converted into low solids, low viscosity CWSF with acceptable stability without the use of viscosity modifiers (dispersants) or stabilizers. Efforts are now underway to determine if the impounded coal fines can be economically cleaned by froth flotation to an ash level of < 12 wt. % and a total sulfur content of 1.2 wt. %.

Jan 1, 1995

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

Aquifer. A formation, group of formations, or part of a formation that contains sufficient satu rated permeable material to yield significant quan tities of water to wells and springs. Artesian. Synonymous with confined; see ground water, confined. Capillary fringe. The zone immediately above the water table in which all or some of the interstices are filled with water that is under less than atmospheric pressure and that is continuous with the water below the water table. Conceptual model. A conceptualization of a field hydrogeologic framework that facilitates the development of analytical field testing procedures. The results of the test(s) may force changes in the initial conceptual model. Conductivity, hydraulic. Replaces the term "field coefficient of permeability." The volume of water at the existing kinematic viscosity that will move in unit time under a unit hydraulic gradient through a unit area measured at right angles to the direction of flow, if the porous medium is isotropic and the fluid homogeneous. Confining bed. A body of "impermeable" material stratigraphically adjacent to one or more aquifers; its hydraulic conductivity may range from nearly zero to some value distinctly lower than that of the aquifer. Flow, steady. Any point where the magnitude and direction of the specific discharge are constant in time. Flow, uniform. At every point the specific discharge has the same magnitude and direction. Flow, unsteady. At any point the magnitude or direction of the specific discharge changes with time. Fluid potential. The mechanical energy per unit mass of a fluid at any given point in space and time with respect to an arbitrary state and datum; the fluid potential is proportional to the head. Ground water, confined. Ground water under pressure significantly greater than atmospheric; its upper limit is the bottom of a bed of distinctly lower hydraulic conductivity than that of the material in which the confined water occurs. Ground water, perched. Unconfined ground water separated from an underlying body of ground water by an unsaturated zone. Ground water, unconfined. Water in an aquifer that has a water table. Head, static. Height above a standard datum of the surface of a column of water (or other liquid) that can be supported by the static pressure at a given point. Homogeneity. Hydrogeologic properties are identical everywhere. Hydraulic gradient. Change in static head per unit of distance in a given direction. Hydrostratigraphic unit. A body of material having considerable lateral extent and comprising a geologic framework for a reasonably distinct hydrogeologic system. Isotropy. Condition in which all significant properties are independent of direction. Porosity. Property of containing interstices or voids; may be expressed quantitatively as the ratio of the volume of its interstices to its total volume. Porosity, effective. Interconnected pore space available for fluid transmission; expressed as a percentage of the total volume occupied by the interconnecting interstices. Potentiometric surface. A surface that represents the static head along a particular specified surface or stratum. Specific retention. Ratio of the volume of water that the rock or soil, after being saturated, will retain against the pull of gravity to the volume of the rock or soil. Specific yield. Ratio of the volume of water that the rock or soil, after being saturated, will yield by gravity to the volume of the rock or soil. Storage, specific. The volume of water released from or taken into storage per unit volume of the porous medium per unit change in head.

Jan 1, 1986

By Jon C. Jenkins

In order to plan the most efficient mine installation, a company should take advantage of all available information and tools. One of the first factors of a coal reserve that needs to be determined as accurately as possible is the quality of coal the mine will have access to during the life of the installation. With the aid of many types of well logs and computor analysis, we are investigating several methods of log correlation to determine such data as moisture, ash, sulphur, and BTU on an in place basis. It may be possible to determine this data more accurately in this manner than by using diamond drill cores for analysis and thus allow for a more profitable mine installation. The production of an underground mine is based on many factors, two of these being roof control and line water, where present either in the roof or coal seam. Using many of the same logs obtained from reserve and active mine areas, we have attempted to determine roof and floor characteristics such as strength, lithology, and moisture properties. Using data obtained from this program, we will make comments on possible length of bolt to be used, possible mining width, and pillar size as they would pertain to these reserves and active mine areas.

Jan 1, 1969

By J. P. Wilson

The Tessenderlo-Kerley Leach process has been shown to be effective in the removal of residual copper from molybdenite concentrates. Concentrates of varying mineralogy, including those containing relatively large amounts of chalcopyrite, have been successfully leached on laboratory and pilot plant scales. The lixiviant system is ammonia and ammonium bisulfite with air / oxygen addition. An abrasive is added which greatly enhances the kinetics, and it is subsequently screened out and reused. The dissolved copper is easily recovered using existing technology. Extraction profiles, reagent consumptions, and mineralogical data are presented.

Jan 1, 1999

By E. R. Hendrickson

About 1/3 of the world&apos;s supply of phosphate rock is produced in a relatively small area of the Florida peninsula east of Tampa. Until this past year, a circle with a radius of about 25 miles and centered on Bartow would encompass the major producing areas. During the past year producing areas have opened in North Florida which promise to vie with the Polk-Hillsborough County area in terms of proven reserves. In addition, new phosphate production is planned for counties to the south and west of the present fields. From the existing production areas, however, more than 19 million long tons of phosphate were mined in 1965. As mining engineers most of you probably are familiar with the methods of mining and beneficiating the pebble phosphate rock. You thus recognize that, although some water quality problems may arise from these processes, there is no potential air pollution problem. To make an economically useful product, however, further processing must take place. It is from this additional processing that potentially damaging materials may be discharged to the atmosphere.

Jan 1, 1966

By Keith J. Henley, Nicholas C. Clarke, Paul Sauter

A detailed investigation of the stability in cyanide solutions of native gold and gold-silver tellurides in a flotation concentrate from the Golden Mile, Kalgoorlie, has been undertaken to assess whether leaching under different conditions can be used to quantify the distribution of Au between native gold and gold-silver tellurides, as suggested by, for example, Chryssoulis and Cabri (1990). The leaching was carried out on +20 µm native gold and gold-silver tellurides separated from a high-grade flotation concentrate and then diluted with barren quartz. The material leached assayed 270 ppm Au and 118 ppm Te and the leach conditions used were:- Stage 1: Leaching in dilute cyanide (0 .1 % ) at pH 9 .5 for 24 hours to dissolve native gold but not gold-silver tel­lurides. Stage 2: Leaching the residue from Stage 1 in strong cyanide (2%) and pH 12.5 for 96 hours to dissolve gold-silver tellurides.

Jan 1, 1995

By D. Lynn, D. Arthur

Infrastructures continue to age and drinking water supplies are becoming scarce in the San Fernando Valley of Los Angeles, California. Frontier-Kemper Constructors, Inc. (FKCI) was engaged by the Los Angeles Department of Water and Power (LADWP) to complete the River Supply Conduit Improvement Upper Reach—Unit 7 Project (RSC7). Two tunnel sections were bored using a 2.64 meter diameter Microtunnel Boring Machine (MTBM) and a 4.12 meter diameter Earth Pressure Balance Tunnel Boring Machine (EPBTBM) to excavate approximately 3,733 meters (3.7 km) of tunnels through highly abrasive late-Pleistocene-age Quaternary alluvial deposits (Old Alluvium) and Holocene age Young Alluvium deposits above the water table. This paper discusses the challenges encountered managing the TBM’s equipment degradation, use of soil conditioners, cutterhead wear, torque and advance rates while maintaining the necessary face-pressures and parameters to limit over excavation and ground settlement.

Jun 13, 2021

By E. J. Rogans, W. N. Cartner

Carbon technology has largely superseded filtration plants as the more acceptable gold recovery technology. This has, over the last two decades, provided a tremendous driving force for the development of new equipment. One of the main focus areas of this technological development is the development of effi­cient interstage screening systems. Several variations of exter­nal and internal screens are available, with the more recent shift away from air cleaned units to mechanically swept units. This paper discusses the development of one such mechanically swept interstage screen and how the development led to the suc­cessful implementation of a carousel type of CIP operation. The first generation Pump-cell emerged as a consequence of the success achieved with the mechanically swept NKM screen, The idea was to modify the screen to incorporate the functions of pumping, screening and agitation in a single drive unit, the screen generating sufficient lift for interstage slurry flow so that all contactors would be at the same level. This sys­tem was further incorporated as a high intensity modular CIP contactor, i.e. low slurry residence times combined with high carbon concentrations. A discussion on the kinetic gold adsorp­tion theory and its manipulation in the design of the pump-cell concept is discussed in a paper published in a previous Randol Conference< 1), Testwork carried out at Vaal Reefs proved the concept of the Pump-cell on a pilot plant scale<2), which resulted in the building in 1990 of the first large Pump-cell plant at West Witwatersrand Gold Mine designed to treat 340m3 of pulp per hour and , even though the plant operated successfully with respect to gold recovery performance, a few problems were experienced with the basic engineering design(3),

Jan 1, 1996

By D. R. Dixon

Since the critical role of oxygen in xanthate flotation of sulphides was established (1) subsequent studies have been concerned mainly with the galena-xanthate system. It is therefore surprising to find at the conclusion of a comprehensive review of the topic by Granville, Finkelstein and Allison (2) that it was not possible for them to draw unequivocable conclusions on the mechanism of xanthate adsorption. It was apparent that some new advances were likely if systems other than galena-xanthate (Pbs/x-) were examined. (2) Specifically a less reactive sulphide such as ZnS may interact with flotation reagents at a slower rate than PbS and more information per unit time gathered. Again ZnS is far less reactive electrochemically than PbS or stated equivalently, it is a poorer semiconductor than PbS. More importantly, the ability of ZnS to act as a semi-conductor can be controlled photochemically rather than by direct doping reactions for which it is difficult to assess the uniformity of doping. Thus the conductivity of ZnS can be made the same as that of PbS by irradiating the ZnS with ultraviolet light at circa 360 n.m. (3)

Jan 1, 1974

By R. Costa, A. Kozak, B. Fukuhara

Introduction The Jacobina mine is located in the state of Bahia in northeastern Brazil approximately 330 km northwest of the state capital city of Salvador and 9 km from the town of Jacobina. The Jacobina Mine (Figure 1) is owned by Jacobina Mineração e Comércio, a wholly owned subsidiary of Yamana Gold Inc. The gold mineralization of the Jacobina mine is hosted within quartz pebble conglomerate reefs of the Serra do Córrego Formation which together with the Rio do Ouro Formation forms the Serra do Jacobina mountain chain. The Serra do Jacobina mountains have been mined for gold since the late 17th century. Since the 1970’s, the Jacobina mined has been operated by Anglo American, Williams Resources Inc., Desert Sun Mining Inc. and now Yamana Gold Inc.

Jan 1, 2007

By Welland L. Ott, Hans J. Rumland

The Falconbridge Dominicana laboratory receives samples from all parts of the operation. Ore, metal and oil samples are taken by operating departments, gas and water samples by the laboratory staff. Physical sample preparation is essentially standard and produces comminuted samples for wet-chemical analysis and X-ray fluorescence analysis (XRF). T he main operating sections of the laboratory are described indicating in each case the type of instrumentation and method used, sample types analysed and comments on problems experienced. Emphasis is given to the sample preparation and X-ray sections especially with regard to the difficulties caused by our heterogenous ore material, calibration of the instrument and operational malfunctions. General problems related to our remote location and the tropical climate are discussed. Limited statistics on instrument availability, and stability, accuracy, precision, etc., are given.

Jan 1, 1979

By Ottmar Burghardt

Sintering of iron ore has undergone a dramatic development world-wide. Today, the annual world production amounts to approximately 600 million tons. At present, the sintering process in competition with pelletizing, seems to offer certain advantages inasmuch as it allows the use of solid fuels. Also, its charging behaviour in the blast furnace is, in general, considered as being better than that of pellets. This is true, in particular, for the charging behaviour and the gas permeability in relation to the grain size. Moreover, instead of charging limestone into the blast furnace, for instance, the basic components which are necessary for the burden materials can generally be supplied in a simpler and more cost-effective way by using basic sinter instead of basic pellets. While in sintering, with basicity rising to the range of 1.6 to 1.8 CaO : SiO2, the capacity increases and the sinter quality shows improvements in most of its characteristics, the pro¬duction of basic pellets generally requires a higher fuel rate, when compared to acid pellets, while production capacity decreases and some of the quality characteristics deteriorate.

Jan 1, 1982

By A. Halim, A. Martikainen, S. GYAMFI

This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine from 2018-2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 2.0 Mtpa.

Dec 23, 2021

By S. Mathur, Pradip

Polyacrylic acid (PAA) was evaluated as a selective flocculant for the dolomite-apatite system. PAA with a molecular weight (MW) of 4 million was found to flocculate both dolomite and apatite. However, the flocculation behaviors of dolomite and apatite were significantly different with 450,000 MW PAA, which was found to be the lowest molecular weight fraction capable of flocculation. In single-mineral tests with a dosage of 2 kg/t PAA, 90% of the dolomite and 35% of the apatite flocculated. Selectivity was achieved in mixed mineral tests. From a feed consisting of an 80:20 mixture of apatite and dolomite, respectively, a concentrate containing 90% apatite was obtained with a 70% recovery. The dolomite rejection was about 75%, which corresponds to a 2% MgO content in the concentrate.

Jan 1, 1997

By T. J. Cox

The Red River is located within the Sangre De Cristo Mountain Range in northern New Mexico. An approximate 12-mile segment of the river from the town of Red River to the village of Questa (Questa) includes several hydrothermal alteration zones. Alteration ?scars? formed as a result of rapid chemical weathering and physical erosion of pyrite-rich hydrothermally altered rocks. Storm water runoff from the scar drainages contributes metal-laden, acidic water to the river and creates a visible plume of discolored water in the river. Acidic runoff reduces the river pH from 7 to the mid 3s for at least 2 hours during large storms and the low pH water continues downstream. Runoff from scar drainages increases some metal concentrations in the river from below chronic ecological criteria to as much as two orders of magnitude greater than acute ecological criteria, and results in acutely toxic conditions for macro-invertebrates. A general improvement in the river?s water quality occurs downstream due to dilution from tributary inflow from non-mineralized watersheds, the natural buffering capacity of the river, and storm water controls at the Chevron Mining Inc. Questa mine.

Jan 1, 2011

By Gordon Hubbard, John D'Acierno

The Randgold Resources Ltd. mine operation in Syama Mali performs whole ore roasting followed by CIL gold recovery to produce gold. The roaster has operated continuously since the plant was first commissioned in 1994. The roaster design throughput is 216 tons per hour (5,184 TPD). Roasting provides for the oxidation of the· refractory components, organic carbon and sulfides. The energy balance for the system requires auxiliary fuel oil to be burned in the Circulating Fluid Bed (CFB) reactor. Energy from the 1200-1350 degree F roasted product stream is recovered and recycled back into the CFB using two fluidized bed coolers; one to directly heat the secondary air and the other to indirectly heat the primary fluidizing air. The basis of the design for the roaster was an extensive pilot plant test program, the results of which were scaled up to the full scale plant design. Due to variation in the feed at the mine a number of roaster modifications were necessary following the initial plant start up. During 1998 ore flotation capability was added to reduce the operating cost for the roaster and increase plant throughput.

Jan 1, 1999

By Sigmund J. Sulinski

All Sanitary District contract documents for new tunnel construction permit the Contractor a choice of four (4) separate alternate tunnel sections. This is the result of a continuing District policy to encourage at all times the use of the most suitable construction techniques and to attract to District construction the broadest spectrum of proven capabilities. Figure 1 indicates the alternate tunnel sections allowed on District contracts as follows: 1. A horse shoe section, ribbed and lagged, and a poured reinforced concrete tunnel liner; 2. Circular section, ribbed and lagged, and a poured in place reinforced concrete tunnel liner; 3. Circular section, ribbed and lagged, and a precast reinforced concrete pipe liner grouted in place; and 4. Circular section, no temporary lining, and a precast reinforced concrete pipe liner to be jacked in place. The Sanitary District now has in operation 10,500&apos; of 5&apos;6" I.D. and 6,500&apos; of 5&apos;0" I.D. jacked tunnel. An additional 5,600&apos; of 7&apos;6" I.D. jacked tunnel is currently under construction.

Jan 1, 1997

By Harold Wahlborg, George Owusu

In a study using butyl diglyme as an organic extractant, essen­tially complete extraction of gold from chloride leach solution was achieved. The extraction kinetics are so fast that the process could be completed in 30 seconds. Except for iron, co-extraction of other ionic species was insignificant. Co-extracted iron species were successfully scrubbed from the loaded organic using 10% HCl solution. High grade, >99.9%, gold was recov­ered from the loaded organic using 5% oxalic acid solution as the stripping agent at a temperature of 70°C to 80°C. Over 99% of the organic-loaded gold was stripped from the organic phase. The butyl diglyme extractant is being tested on a variety of gold-bearing feedstocks. Presented here are results obtained from two gravity concentrates.

Jan 1, 1999

By Dave Watson

Henderson Mine personnel have more than 20 years experience and have placed more than 400,000 m3 (520,000 cu yd) of shotcrete and concrete. Over the last 20 years, the mine has used a variety of equipment to place concrete, wet shotcrete and dry shotcrete and is constantly trying to cut costs and increase efficiencies. Recently, the mine received a state-of-the-art wet shotcrete placer. The batch plant was automated, and a mobile concrete-form jumbo was fabricated. The mine will also receive a new concrete transport truck. Henderson’s background The Henderson Mine is owned by Climax Molybdenum Co., a unit of Amax, Inc. It is an underground, primary molybdenum producer near Empire, CO. The mill is located between Silverthome and Kremmling, CO and is connected to the mine by 16 km (10 miles) of underground and 8 km (5 miles) of surface track. Except for the ore haulage system which is powered by overhead trolley, all mobile equipment is rubber-tired and diesel-powered.

Jan 1, 1992