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By A. Griffiths, G. Vickell

"INTRODUCTIONA successful cyanide destruction process has to ensure environmental compliance at reasonable cost. That this is possible with hydrogen peroxide is shown by the fact that over twenty gold mines either already use H2O2 or intend to start using it within the next few months. About half of these mines are in Canada.This growth is remarkable, considering that the first treatment plant to use H2O2 for detoxifying cyanide was commissioned less than five years ago at Ok Tedi, in Papua New Guinea.Hydrogen peroxide is being applied to a wide range of situations, including:Treatment of CIP pulps; examples: Ok Tedi, PNG; Hope Brook, Nfld.Treatment of barren bleeds and filtrates; examples: Nickel Plate, B.C.; Puffy Lake, Man.Treatment of tailings pond discharge; examples: Detour Lake, Ont., Page Williams, Ont.Treatment of excess heap leach solution; examples: Hope Brook, Nfld; Gordex, NS.Treatment of barren heaps after heap leaching; examples: Alhambra, NV; Wharf Resources, S.D.Treatment of pond reclaim water to prevent either ""preg-robbing"" or depression of gold-bearing pyrite in a flotation step; example: Getchell, NV.Treatment of backfill to prevent possible groundwater contamination; example Hope Brook, Nfld.Treatment of tailings ponds to prevent bird kills; example: Paradise Peak, NV.""Emergency"" units to deal with unusual events such as freak storms or dam failures."

Jan 1, 1989

By J. Böhlke, B. Friedrich, E. Hecker

The legislation for the disposal of heavy metals contaminated substances is still going to be tightened up in the future. The main criteria for the utilization or deposition of these residues are the content and the water solubility of these metals. Through this, the use of slags from the lead-and zinc-industry in road building may become limited or even not possible at all. From an economic point of view this would lead to Pb/Zn losses and costs for safe dumping. This paper investigates the feeding of the reducing agent via hollow electrode DC smelting and the yield of metal reduction. After carrying out thermodynamic calculations, the process window conditions for electric-arc furnace tests were determined. Doing this, the zinc could be reduced, evaporated and recovered as an oxidic intermediate product flue dust, while the lead was present either in flue dust or in metallic form. The zinc content in the final slag could be reduced by up to 90%. The slag product has undergone an eluation test which allows it to be used as building materials. Keywords: zinc reduction, lead reduction, hollow electrode, slag treatment, electric arc furnace

By Clement K. Chase

Since the dawn of cyanidation leaching techniques for precious metals, certain manganese-bearing silver ores have been a problem due to low silver extraction. Since simultaneous occurrence of silver and manganese is common in nature, this situation has made many otherwise attractive silver deposits uneconomic in the past. Several older techniques have been useful but at $1.29 per ounce of silver, the economics were unfavorable. With the new look in silver prices and some improvements in processing technology, neglected silver districts offer new promise.

Jan 1, 1981

ALTHOUGH the development of the various flotation processes during the last 8 years has been so revolutionary, this development has been, until recently, entirely confined to the separation of the gangue from the mixed metalliferous sulphides.The desirability of finding some method of separating the independent sulphides from such a miXture, by means of flotation, has long been recognized. ThIS need was emphasized when the slimes resulting from the grinding of Broken Hill sulphide ores were for the first time successfully dealt with by the Mineral Separation Company's process on the Central mine. This process proved the practicability of separating the sulphides of lead and zinc as a mixed concentrate from the gangue present in slime. Although this was a very notable achievement, the process has not been generally used, owing to the mixed lead and zinc concentrates resulting from the treatment being acceptable neither to the zinc nor the lead smelters.Although the introduction of eucalyptus oil in minute quantities as an emulsifying agent has simplified the work of the subsequent tabling of mixed sulphide concentrates, rendering unnecessary the burning off or removal of the oil, there will always be a considerable quantity of slimy product too fine to settle on the moving surface of the concentrating machines, and therefore requiring other means for its division into lead and zinc concentrates.

Jan 1, 1912

By Ramona Prillhofer

Salt slag is a waste product produced by the recycling of aluminum. In most European countries (e.g. Austria, Germany) the landfill disposal of this waste is forbidden because the slag contains soluble salts and these represent a potential source of pollution to the surface and groundwater. Additionally, consisting metal and some compounds in the salt slag can react with water and resulting from this, noxious gases are generated. The recovery of useful materials from these wastes is accordingly both environmentally necessary and economically feasible. This study describes a complete recycling-process for the salt slag, which includes a leaching-cristallization-process to obtain the oxidic residue, a pyrometallurgical-step to clear the oxidic residue and finally an extensive characterization of the achieved products. Due to the increasing price of raw materials, the utilization of the oxidic residue into commercial products has been investigated and application possibilities will be discussed.

Jan 1, 2009

By G. I. Mathieu, R. W. Bruce

Flotation schemes for the separation of molybdenite from other minerals are based on utilizing the Inherent hydrophobicity of molygdenite (Fuerstenau1). This natural floatability was attributed to the crystalline structure of molybdenite by Gaudin et al.2 who suggested that any surface formed by the rupture of van der Wall's bonds should be hydrophobic and, therefore, naturally floatable. Other authors argued that "natural floatability" is dependent of adsorption of hydrocarbon ions and/or molecu1es on the surface of the minerals. This theory, albeit-c questioned 1,2 has long been recognized in actual practice of molybdenite flotation as the latter in carried out with hydrocarbons, such as fuel oil, kerosene and stove oil. Although conferring ready floatability to molybdenite, these presents generally have little effect on other sulphides and silicates. However, talc is a noteworthy exception because of its innate floatability4. Not withstanding the reason for this behavior which has also been attributed to crystal structure2 its end results as in the case of molybdenite is an immediate flotation response to frothing oils arid kerosene, as was observed by Baranovski5, Sutherland and Wark6.

Jan 1, 1974

Treatment of the Siirt-Madenk÷y Ores by Flotation

Sep 13, 2010

Wastewaters from Mining Projects both gold mining and coal mining generally have minerals in solution or very fine material which does not settle out quickly. These waters in the past have been discharged into the nearest water course and caused extensive pollution.

Jan 1, 1986

THE old mill erected by the .Irvinebank Company consisted of 10 heads of stamps (850 lb.), rock-breaker, Hartz jig, two Krupp tables, two Luhrig vanners, three sand-pumps, one mixer; six flotation vessels, and the necessary settlers. Power was supplied by a small colonial-type boiler, and 10-in. x 15-in Tangye engines. The ore was darted from the mines to the mill and hand-fed, into the rock-breaker, and the broken product elevated into the batter bins and fed into the stamps, the pulp from the stamps passing to a classifier, the spigot to jig, tables, and vanners, the overflow from the classifier passing to settlers. After the removal of bismuth-wolfram concentrates, the pulp was pumped to the molybdenite flotation plant and the olybdenite recovered by flotation.A commencement was made with the erection of the first unit (20 heads) of the new mill in August, 1917, and milling and concentrating commenced in February, 1919.

Jan 1, 1920

By W T. C Kendall, H D. Ngo

Garden Well is a shear-hosted Archaean orogenic gold deposit located 100 km north of Laverton, Western Australia. The Garden Well processing plant is designed for a nominal 491 t/h milling rate and annual capacity of 4 Mt. The plant has three key innovations:1. a scrubbing circuit, expected to reduce grinding power consumption by up to 20 per cent2. a secondary cycloning/gravity circuit, providing a second opportunity for gravity gold recovery (additionally, the circuit effectively increases the leach residence time of the coarse gold bearing fraction of the leach feed by approximately 60 per cent, without any additional tankage)3. the use of mid-stream oxygenation to enhance gold recovery.The Garden Well deposit is free-milling with overall laboratory gravity/leach gold recoveries exceeding 95 per cent at a P80 grind size of 150 ¦m. Three mineralogical domains have been identified: oxide, transition and fresh, with the fresh domain having subdomains of fresh ultramafic and fresh shale. There is a high component of gravity recoverable gold in all three domains.This paper will discuss these innovations and the design challenges and the risk mitigation strategies that were adopted to ameliorate the prototyping risk. The performance of the plant since commissioning together with lessons for the future will also be presented.CITATION:Smith, R J, Kendall, W T C and Ngo, H D, 2013. Treatment plant innovation at Garden Well, in Proceedings World Gold 2013 , pp 315-324 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Vic Sterner

As cities and towns continue to grow, the need to install sewer, water, gas and other utilities becomes a necessity and the blasting of trenches for these service lines probably constitutes one of the most important forms of blasting in built-up areas. There f o re, understanding how explosives can be safely used in the most efficient manner is of prime importance. The need for protection against flyrock must be emphasized. The first consideration is that all explosive c h a rges should be located well down in the blastholes. The golden rule is to ensure that the depth of top stemming is never less than the burden on the hole. In the case of shallow holes, the minimum depth of stemming should not be less than 18 times the charge diameter, if airblast and flyrock are to be controlled. If there is a doubt, then additional cover and/or blasting mats should be used. Putting too much burden on blastholes is another possible cause of flyrock and raising ground vibration levels. Overburdening of explosive charges will also result in the blastholes not breaking to grade. This in t u rn re q u i res additional drilling of shallow holes down in the trench to achieve grade, thus further increasing the h a z a rd of flyrock .

Jan 1, 2004

By Tom Treleaven, Andrew Williams

The town of Greenwich, CT, an exclusive suburb of New York City awarded several contracts for the installation of sanitary sewer in the North Mianus section of town. The Valley Road section was the most challenging from a rock excavation standpoint. The cut was up to 14 ft (4.25m), with adjacent utilities [20 in. (500mm) water, 6 in. (150mm) water and 8 in. (200mm) gas] located to within 5 ft. (1.5m) of the proposed sewer trench. Rock types varied but were ultra metamorphic in nature, ranging from quartzites, granite gneiss and various types of migmatities.

Jan 1, 2004

By Tom Treleaven, Andrew Williams

Several contracts were let in Greenwich, Connecticut, for the installation of a sanitary sewer. The majority of the excavation was in rock and involved numerous challenges due to the following conditions:

Jan 1, 2003

By Andrews Allen

WE all remember when, a few years ago the preparation of coal was nothing but a matter of having somebody at the face or somebody in the railroad car pick out the impurities; also the sizes were generally' made" over a bar screen. Anything that was black was coal; and the only matecia1 picked out was the slate or rock-impurities that could be distinguished by eye or by hefting. This was all right as long. & coal could be sold at. a good price. After all, we are all in business to -make the most money honestly out of a certain acreage of coal and a certain plant. For this purpose what is required is the greatest possible recovery of marketable coal and the highest market price.

Jan 1, 1929

DEFENSE Materials Procurement Agency has been moving rapidly to encourage copper industry expansion programs. Although copper production is at a high level, a shortage exists on a world-wide basis as well as on the domestic scene. Projected expansion programs will not ease this current demand for most of them are 2 to 5 years off. Refining facilities are adequate but there is a shortage of ore and scrap, and it is for this reason that the expansion programs are directed at developing more sources of supply. The domestic expansion programmed thus far and understood to have been arranged with price escalation should the domestic price go to 271/20, were summarized by American Metal Markets as follows (dates of announcement are given in parenthesis: .1-Copper Cities Mining Co.'s, $15,000,000 expansion near Miami, Ariz., to be operating about 1954. DMPA will buy 22,500 tons of copper a year up to a given amount on an agreed price of 23¢ per pound, with some exceptions and depending upon salability at a higher price to other purchasers in the U. S. (September 25th). 2-An RFC loan of $60,000 to North Butte Mining Co. to be paid off on the basis of deliveries at a purchase price of 241/20 per pound (September 25th). 3-A $25,000,000 expansion program by Phelps Dodge to provide 38,000 tons per year by late 1954. DMPA would purchase it at a price of 22¢ per pound up to 112,500 tons providing other purchasers in the U. S. will not pay a higher price (September 26th). 4-Anaconda Copper Mining Co. $40,000,000 expansion in Nevada to provide more than 30,000 (might be increased to 45,000) tons per year. DMPA would purchase the copper at 250 per pound for a limited period of time if it is not salable to industrial users at above this price. Production would start around 1953 (November 14th).

Jan 1, 1952

AN economist at MIT provided Americans with myth destroying information which should prove effective against the gentlemen of the extreme left. For a number of years they have charged that a small number of companies in each industry has been grabbing more and more of the industry's business. M. A. Adelman has shown that the concentration of business in the hands of big corporations has not shown any sign of growth during the last 50 years. Quite the contrary, there has been a slight decline in this concentration, according to Adelman. There are more small companies per thousand population than ever before. Bearing this out is the fact that International Harvester is now doing 41 pct of the possible market against a former 85 pct; American Can Co. has dropped from 90 pct to 50 pct; American Smelting is down to 31 pct compared with 90 pct; and lastly, U. S. Steel which has plummeted from 65 pct to slightly more than 30 pct of the steel market. Declines of the same proportions have hit big companies in other industries. Price cuts on Detroit's 1953 automobiles indicate that even among the biggest competition is still one of the most important household gods. Big business is still slugging it out for the attention of the American consumer. It's a battle which can only have one result-benefit to the man who buys.

Jan 1, 1953

By G. R. Robinson

Aggregate resources consist of sand and gravel, and crushed stone. They are large-tonnage, bulk-minable mineral commodities that are used in construction and industrial activities (Tepordei, 1999, 2001).Rates of aggregate production, use and mine permit approval in the mid-Atlantic region differ by population density. These rates are influenced by economic and human factors, such as demand, costs, land availability and community opposition. In some areas, the local availability of aggregate is limited. This is due to the lack of suitable local source materials for aggregate, the loss of potential high-quality aggregate resource production sites by preemptive land development and restrictive zoning (resource sterilization), and the difficulty of developing and permitting production sites for aggregate.

Jan 1, 2004

By Arthur Grounds

Historical In the course of a paper which is necessarily limited in length, such as the present one, it is obviously impossible to describe in detail the history, development, and present position of coal preparation in Western Europe. Great Britain has been blessed with large deposits of excellent coal of nearly every type, ranging from the high-grade anthracites of South Wales, which are characterised by their very low ash and volatile con-tents, to the superb coking coals of South Wales and Durham -probably the finest in the world -with their low ash and sulphur contents, the latter constituent often well be-low l per cent. Gas coals abound in Lancashire and Yorkshire, while coals from the East Midlands, Northumberland, and Scotland are excellent for steam-raising and other industrial purposes. The excellent quality of these various coals has, in years gone by, ensured ready .sales abroad and it is not surprising, therefore; that methods of coal preparation were largely developed on the Continent in an endeavour to upgrade the inferior fuels found there, so that the prepared product could compete with British coals on the European market.

Jan 1, 1951

By Dennis Asmussen

The peatlands of the U.S. and Canadian parts of the Upper Great Lakes region have a long history of modest utilization in agriculture, forestry, horticulture, and as natural undisturbed areas. Only recently have they been assessed as potential sources of non-renewable or renewable energy. This new interest in peatlands, should current proposals be realized, might mean the commitment of millions of acres to energy production purposes. The magnitude alone of this potential utilization of peatland signals the possibility of substantial environmental disturbance, local resource shortages, resource use conflicts, and social and economic change. Peat- land resource managers in the region are just beginning to weigh the advantages and disadvantages of large-scale peatland utilization. The Minnesota Department of Natural Resources has made a considerable effort to study peat resource management issues and will shortly make recommendations to the state legislature regarding utilization alternatives. What follows is a general discussion of peatland utilization and management trends in the region with a focus on Minnesota and its peatland management efforts.

Jan 1, 1980

By T. Tholana, P. N. Neingo

"Mining companies globally are currently facing severe economic and financial challenges. In addition to global challenges, the South African mining industry has to face other operational challenges that are unique to the country and which threaten the survival and competitiveness of the industry. Profit margins are being squeezed by rising costs and decreasing commodity prices, while labour productivity is greatly affected by intermittent labour unrest. This paper analyses how the South African gold mining industry has performed pre-, during, and post the global financial crisis of 2008. The competitiveness of the industry in terms of labour productivity and industry cost curve position is analysed for the period 2006–2013 to assess the impacts of both the global financial crisis and labour unrest. An analysis of the South African gold mining industry is presented at company as well as mine level. Productivity measure in this paper is limited to labour productivity, in line with limited reporting on productivity. All the data analysed was obtained from the public domain. IntroductionSouth Africa dominated the world as the number one gold producer until 2009 when China took that position, and today South Africa ranks fifth after China, Australia, Russia, and the USA. According to Statistics South Africa (2009), South Africa still had about 30 years of production in the gold sector, a forecast that fluctuates based on the day’s modifying factors. Although South Africa has a comparative advantage in terms of minerals endowment, there are challenges faced by the mining industry that hinder translation of the comparative advantage into a competitive advantage. The industry continually seeks to address these challenges to remain competitive in global markets while addressing national and community needs.Neingo and Cawood (2014) argued that stakeholders in mining are continually concerned with mine management’s ability to translate use inputs effectively into quality outputs. They further suggested close monitoring of effective utilization of people, materials, and money to obtain maximum production of commodities under given conditions. Productivity is measured in various ways, including unit cost, output per employee, and output per unit capital equipment"

Jan 1, 2016