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By C. Richard Tinsley

Mineral economists debate whether to call the deep-ocean nodules "manganese nodules," "nickel nodules," "polymetallic nodules," or even "ferro-manganese nodules." It is nickel and copper that are generally regarded as the main targets in the nodules. Processing considerations are thought to virtually dictate that Deepsea Ventures will produce high-purity manganese metal (at least if it follows a hydrogen chloride leach), whereas other groups have been focusing on the selective extraction of copper, nickel, cobalt, zinc, and molybdenum, while rejecting manganese to tails. Solvent extraction appears to be the primary multimetal extraction technique (except for manganese). These processing considerations indicate that metal production f, or Deepsea Ventures is essentially a co- product system (manganese recovery is necessary to recycle chloride ions) while the other groups can more easily approach the metals as selective co-products (e.g. recovering nickel and copper, and rejecting cobalt). Some zinc may be produced as a co-product, as it may have to be removed in the solvent extraction process.

Jan 4, 1975

With the proclamation of the Environmental Protection Act, 1971-80, the Environmental Protection Authority and Department of Conser- vation and Environment were established to enhance the quality of the environment. Proposed gold developments of all scales can be referred to the Authority in the form of a Notice of Intent. Environmentally significant projects might then require preparation of an Environmental Review and Management Programme. Current environmental issues include the'effects of clearing by prospectors,, mine dewatering and tailings disposal. INTRODUCTION In the past, the environmental aspects of gold industry related activities have received little attention. However, with the proclamation of the Environmental Protection Act, 1971-80, mechanisms were instituted which allowed both for referral of projects to the Environmental Protection Authority (EPA) and establishment of the Department of Conservation and Environment. As well as providing assistance to the EPA on referred projects, the Department is concerned about a number of environmental issues associated with the gold mining industry.

Jan 1, 1982

By H. M. Merry

THE graphic methods and records described in this article have been developed, with satisfactory results, for the use of executives of the Chino Copper Co., in Hurley, N. Mex. Particular attention is directed to the use of large wall-charts, the quick reference display of large charts, the scale notation of metallurgical charts, the inclusion of mesh extraction on screen analysis diagrams. To properly comprehend the operation and metallurgical results from a concentrating plant, a daily record of essential data is kept, usually involving the dry weight of ore milled or treated, dry weight of concentrate or metal produced, assay values of heading, assay values of tailing, assay values of concentrate, and percentage of extraction or recovery. In addition it is often necessary to record moisture, pulp density, or dilution; percentage of weight of oils and reagents employed; screen analyses of grinding conditions, oversize, etc.; assay values of non-valuable or interfering substances; cost data; and such special information as may be required.

Jan 9, 1919

By B. Dubreuil

Arsenical bearing deposits are posing an increasing challenge for the mining industry. In particular, mineral processing of arsenical sulfidic ores for base and precious metals recovery tend to produce problematic arsenical tailings. This arsenic being present as sulphide or oxide, tends to dissolve, contaminating surface and underground waters. To meet the environmental regulations, it is often required to stabilize the arsenic in a more insoluble form. Nichromet has developed a new patented technology using vitrification of the arsenic oxide in an economical way, giving a stable solid, well below the environmental regulations upon leaching. This technology involves oxidation of As (III) to As (V), by using a low cost natural oxidizer and transformation of the produced arsenic oxide into calcium arsenate, which is not volatile at the melting temperature of the glass. This technology would be advantageously applied on most cases around the world where sulphide concentrates are oxidized in a fluidized bed or smelted.

Aug 1, 2013

By G. T. Adel

The flotation behavior of a -28 mesh Pittsburgh No. 8 coal sample is investigated through the use of Scanning Electron Microscopy in conjunction with Image Analysis. Release analysis is used to generate the flotation products, which are then characterized to provide the particulate composition in terms of pyrite, mineral matter and carbonaceous material. The results of this investigation indicate that the material recovered in the first stage of release analysis tends to be well-liberated carbonaceous material. This is followed by an increase in the recovery of middlings and fines in the later stages of the process. Any free carbonaceous material remaining in the tailings from the release analysis test tends to be associated with the very fine sizes (-400 mesh). Pyrite recovery is attributed to the hydrophobicity provided by small inclusions of carbonaceous material, since the amount of truly liberated pyrite particles (i.e., 100% pyrite) present in the sample is found to be negligible.

Jan 1, 1994

By Jorma Miettunen

The Plant. The annual production of the Pyhasalmi mine is 900 000 tons of copper- zinc-pyrite ore containing approximately 0.7 % Cu, 2.5 % Zn and 30 % S. During 1976...1981 altered surface ore, 850 000 tons in all, was also treated at the concentrator. The surface ore was crushed and ground in a separate plant and was then fed into the copper or zinc flotation or was flotated in its own circuit, depending on the degree of alteration and the content of copper and zinc in the ore. The surface ore was exhausted in October 1981. Flotation comprises three consecutive flotation circuits; copper, zinc and pyrite circuit. The zinc circuit includes an open circuit roughing and scavenging. The scavenger concentrate and cleaner tailing are pumped to the middlings flotation. Rougher concentrates of the open circuit and the middlings flotation are pumped to cleaning which includes four stages. Figure 1 describes the flowsheet of the zinc circuit.

Jan 1, 1982

By J. Hanna, R. Kalathur

Over the years, Alabama's coal industry has generated, during mining and cleaning operations, about 150 million st of fine waste coal, with this total increasing at a rate of 2 million stpy. Reclamation of the fine-size wastes (containing 20% - 60% clean coal by weight) provides, free of charge, mined and crushed feed stocks for coal recovery. Also, the removal or recovery of pyrite from the tailings should eliminate a major source of acid-water pollution. Tests were made on the impounded wastes and current plant discharges to recover the coal fraction by sizing, gravity and flotation techniques. Gravity separation of the +100-mesh material produced commercial-grade coal averaging 7.6% ash, 0.8% sulfur and 13,471 Btu/lb. However, the coal yield, at about 31 % - 56%, was relatively low. Froth flotation, using mechanical and froth column methods, gave similar coal products at much higher coal recovery rates of 87% - 93%. This coal analyzed 10% ash and 1.1% sulfur.

Jan 1, 1993

By R. Schuhmann, A. M. Gaudin, J. Dasher

Occurrrences of South African uranium have been known qualitatively for over twenty years, but no account was taken of them because of their low grade. In 1945, known uranium deposits were few, but their grades were 20 to 100 times higher than South African ores. Viewed in this light, the exploitation of South Africa's uranium is revolutionary indeed. Development of various analytical procedures capable of dealing with the needs of the project accounted for one-half of the cost and included: a) simple and automatic radiometric analytical procedures, b) sampling procedures appropriate to prevent sample contamination, c) procedures for sample and record-storing to accommodate many thousands of analyses per month, d) chemical methods giving high accuracy analyses for high grade samples not at radioactive equilibrium, and e) development of rapid procedures having moderate accuracy for low grade samples i.e., mill tailings and barren liquors. This task is continuing today with major improvements coming from time to time.

Aug 1, 1956

By Walter Küng

The Henderson Coarse Ore Conveying System is a three flight belt conveyor system transporting primary crushed molybdenum ore 24 km (15 miles) underneath the North American Continental Divide. One of the conveyors is 16.8 km (55,200fi) in length with 8,200 kW (11,000 HP) of installed power. The overland conveyor contains 11 vertical curves and 9 horizontal curves, some with radii as small as 1,500 m. he system began full operation in December 1999 and is one of the longest and most complicated belt conveyor systems yet constructed. he design of this conveyor system utilized many innovative engineering concepts including low-energy belt covers, low-resistance idlers, torque-controlled tail drives, combined gravity and active winch take-up systems, small radius horizontal curves and belt turnovers. his paper reviews the start-up of the system, discusses the success of the design and addresses the lessons that can be learned from the first 4 years of operation of this unique conveyor system

Jan 1, 2004

By William Petruk

Volcanogenic base metal ores contain about 0.5 to 7 g/T Au, commonly as an intermetallic compound with Ag and/or Hg, and to a small extent • "invisible gold" in pyrite and arsenopyrite. The Au-bearing phase (electrum, Au-Ag-Hg alloy, etc.) generally occurs as fracture fillings in pyrite, arsenopyrite and chalcopyrite, and rarely • minute inclusions in pyrite and arsenopyrite. The Au-bearing phase in fractures generally occurs • small grains, and is frequently associated with galena, tetrahedrite and other late minerals. The gold is readily liberated from fractures and recovered by flotation in Ca concentrates. Copper concentrates usually recover around 60% of the gold when the ore grade is around 3 g/t. Higher recoveries are obtained for higher ore grades, and lower recoveries for lower grade ores. Lead and zinc circuits act as scavengers for gold, and recover all the exposed gold attached to small particles. Only unliberated gold, "invisible gold" and very minute gold grains attached to large particles are lost to tailings.

Jan 1, 1990

By P. E. Snoek, R. L. Gandhi, C. S. Miller

Slurry operations are an integral part of mineral processing. There is therefore reason to consider using slurry pipelines for long distance mineral transportation. This paper reviews the current state-of-the art of such systems and, in particular, the design factors which must be addressed. It also discusses the selection of major components such as pipe, pumps, valves and storage facilities. Finally, the major steps required to determine the economic feasibility of a slurry system are listed and the major advantages and disadvantages of slurry pipelines compared with other forms of land transport are summarized. SLURRY PIPELINES: GENERAL OVERVIEW Minerals Transported Long distance slurry pipelines have been successfully used for transporting coal, iron concentrate, copper concentrate, limestone and phosphate. Additionally, several tailings disposal pipelines of considerable size and length have been built, but these generally are not categorized as long distance commercial mineral transportation systems. Table 1 lists selected examples of commercial slurry pipelines.

Jan 1, 1986

The Copper Concentrator at Mount Isa Mines Limited treats approximately 6 Mt of chalcopyrite ore annually. The ore is currently sourced from the 1100 and 3000 orebodies at Mount Isa. Chalcopyrite is the only significant copper bearing mineral, with pyrite, quartz and dolomite being major gangue minerals. Ore is typically 10% chalcopyrite, 11% iron sulphides and 79% non-sulphide gangue. Copper ore is treated through two autogenous mills, two ball mills and a flotation circuit. The autogenous mills replaced a crushing plant, two rod mills and two primary ball mills during 1991. For routine analysis of concentrator performance, composite samples of mill feed, final concentrate and tailings are generated every 4 week period. All samples are sized and size fractions are assayed. Recovery of mineral species to the concentrate are then calculated for each size fraction. Sometimes liberation analysis was also performed by QEM*SEM (Quantitative Evaluation of Material by Scanning Electron Microscope).

Jan 1, 1990

By J. Hanna, J. Jung, I. J. Anazia

Electrothermal production of elemental phosphorous (P4) generates substantial amounts of highly toxic phossy water and sludges. Because of their high phosphorous contents and lack of reliable processing technology, large tonnages of these hazardous wastes have accumulated from current and past operations. To date, the sludges are stored in ponds or above ground in special containment vessels at various locations around the country. Two samples of electric furnace phosphorous sludge (obtained from the Tennessee Valley Authority (TVA) in Muscle Shoals, AL and FMC Corporation in Pocatello, ID) were investigated using physical separation techniques to recover the elemental phosphorous and to render the residual material nonhazardous. The techniques tested include sizing, froth flotation and dispersed air oxidation. Flotation and sizing produced concentrates containing 69% - 90%P4, with recovery in the range of 60% - 87%. Dispersed air oxidation of the fines and tailings products was effective in the removal of an additional 10% - 15% of the P4 in the sludge.

Jan 1, 1993

A new $18-million hydrometallurgical ore treatment facility for the recovery of molybdenum oxide was dedicated at Climax, Colo., on November 19 by Climax Molybdenum Co., division of AMAX. The Company has been producing molybdenum from molybdenite (MoS2) ores since 1918. Now oxide values, formerly lost in the sulfide flotation plant tailing are to be processed to yield about 3 million Ib per year of metal. In 1965, Climax produced about 50% of world molybdenum from sulfide ore. This ore is mined at the rate of 42,000 tpd. The annual production of concentrate is 100 million lb containing 90% to 92% MoS2, or about 50 million lb of metal. As only a relatively small portion of the total Climax production is sufficiently enriched in oxide molybdenum to process through the new plant, 5700 tpd of selected ore containing 1.5 lb of Mo per ton is now treated by the new process.

Jan 12, 1966

By Murray G

This paper outlines the processes involved in acid generation from sulphides and the key factors in identifying and predicting time dependent changes in the nature of acid mine drainage (AMD). The initial characteristics of mine water; whether drainage from exposed mining faces, runoff and seepage from waste dumps or seepage from process tailings; do not necessarily reflect the long term potential for AMD. The ultimate quality of mine drainage is a function of the interaction of many chemical, physical, biological and engineering (operational) factors. Techniques are available that can predict the qualitative nature of acid generation and mine drainage quality but accurate quantitative predictions are essentially impossible at the present time. As more and more mining operations exploit sulphide ore, the AMD and acid waste issue will become a. far greater concern. The significance of time dependent factors in the production of acid mine drainage-.is not just restricted to particuL.ar mine sites but needs to be recognised by the mining industry as a whole.

Jan 1, 1988

By R. W. Mancantelli, J. R. Woodward

In 1947 a large low grade deposit of uranium was located in the northwest corner of Saskatchewan, in the Beaverlodge property of Eldorado Mining & Refining Ltd. Most of the values occur as thin seams and as coatings on other minerals, and the ore, which is light and friable, is not amenable to the usual gravity methods of concentration. The acid leaching process developed to retreat the company's Port Radium tailings was also impractical, as the percentage of carbonates is high and the percentage of sulphides relatively low. Construction of the mill building and installation of equipment, both scheduled for 1952, awaited selection of a satisfactory ore dressing process on or before Oct. 1, 1951. An extensive research program on dressing of ores from the Ace mine therefore was undertaken by the Mines Branch in Ottawa, a research team at the University of British Columbia and an ore dressing group at the company's Port Hope refinery.

Jun 1, 1955

By D. Dimitriadis, T. Polglase, M. M. Botz, W. Phillips, R. Jenny

Cyanidation processes for the extraction of gold or silver frequently involve the processing of sulfurcontaining solids that react with cyanide to form thiocyanate. The formation of thiocyanate is an undesired side reaction, and in many cases thiocyanate formation results in a prohibitively high cyanide consumption. With the increasing number of gold and silver mining projects that involve the processing of sulfide ores or concentrates or that utilize a biological sulfur oxidation process, more attention is being focused on minimizing thiocyanate formation and in treating solutions to eliminate toxicity associated with thiocyanate. Though not yet commercially applied, there are several processes available to recover cyanide from thiocyanate to reduce tailings toxicity and to allow the reuse of cyanide otherwise lost to thiocyanate formation. This paper presents an overview of processes available for recovering cyanide from thiocyanate along with estimated operating costs for the processes. Pilot testing data suggests that in some cases cyanide can be recovered from thiocyanate for approximately the same cost as newly purchased cyanide.

Jan 1, 2002

By James L. Hendrix, R. Y. Wan, David W. Kappes, Jinrong Zhang, M. C. Fuerstenau, Terence E. Albert

A sulfidic flotation tailings ore, containing 1.14 gpt Au and 242.53 gpt Ag, was treated by low temperature chlorination roasting followed by cyanide or chloride leaching. Eighty per cent of Ag was recovered by cyanide leach when the ore was roasted at 350°C with 50 kg/ton calcium chloride. About seventy per cent of Au was made cyanide amenable by chlorination roasting at 400°C. A better Ag recovery, ninety per cent or over, was achieved by chloride (NaCl+HCl) leach. However, Au recovery was very poor by chloride leach. Ferric chloride, calcium chloride, and cupric chloride were compared as chlorinating agents for their effect on Au and Ag recovery. The study found that low temperature chlorination roasting is very effective for recovering Ag associated with stibnite and stannite. The best chlorinating agent for the test ore was found to be calcium chloride. Parallel roasting-leaching tests indicated that chlorination roasting was far superior over oxidation roasting for both gold and silver recovery.

Jan 1, 1993

By J. E. Forciea, O. E. Palasvirta, L. G. Hendrickson

All pilot and commercial plants working with Mesabi Range taconite employ wet magnetic separation. Progress is being made with a dry magnetic process,9-11 but this has not yet been applied to taconite except in the laboratory and pilot plants. Flowsheets in all five plants are similar, including multiple stages of grinding, each followed by magnetic separation, which rejects a finished tailing. The flowsheet in Fig. 1 is used in the preliminary and commercial plants of the Erie and Reserve mining companies and in Unit C of Oliver's Pilotac plant. At Erie the desliming operation is omitted. In the Reserve plants two ball mills are used with each rod mill. Pilotac uses flowsheet 2 in Unit A-B and has also tested flowsheet 3. Principal differences in the three flowsheets are the number of grinding stages and the type of roughing. The terms open- circuit roughing and closed-circuit roughing are best defined by the diagrams.

Jan 12, 1958

By M. Faure

The experiment with backfill at Harmony was mainly an attempt to improve the ground conditions in a particularly tricky section of the mine. A deslimed tailings system was selected for financial reasons, ease of installation, ease of operation and its low level of mechanization. The design of the system has three aspects: firstly, to define the parameters of the backfill material itself; secondly, to design a reliable plant which could consistently produce the desired material in sufficient quantities; and, thirdly, to design a fill distribution system for maximum reliability in the shaft, minimum pipe line velocity, pressure and cost in the horizontal sections and consistency and reliability at the delivery end. The system was successfully constructed and commissioned in a short space of time at a relatively low cost. It has now reached its full potential, and very encouraging results have been achieved with regard to cost savings, ground conditions, ventilation and accident statistics.

Jan 1, 1988