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By Jonas Olsson

"The picture of China as an antiquated continent is changing rapidly and fast-forwarding progress is a fact in most infrastructural fields. Mining is not an exception. China is today the largest producer of aluminum, coal, steel, zinc, tin, lead and manganese and the country’s mineral resources comprising approximately 12% of the global reserves ranks them number three in the world after US and Russia.In order to feed the growth industry is needed to take extra ordinary strides to improve supply of raw material and Chinese mines are continuously being upgraded with the latest western technology to meet the increasing domestic demand of base metals.In Anshan located in China’s northeast province Liaoning we find one of the fastest developing mining companies, Angang Iron & Steel Group Co. Ltd. With their six mines that together process approximately 60 M ton iron ore/year Angang Iron & Steel Group Co. Ltd is the largest iron ore company in China. The group’s thorough pre-studies and technical evaluations over the past five years have made them very successful in both plant upgrades of existing operations and green field projects.INTRODUCTIONWe live in a time when the world market is gradually acclimatising to the global consequences of “The China effect”. An effect caused by a formerly sleeping giant nation that during the last years has awakened and developed beyond comparison, primarily because of booming infrastructure projects and demand for capital and consumer goods"

Jan 1, 2006

Mine ore, reduced to minus 71/2 in. by primary crushers, is stockpiled. Size reduction of the reclaimed material by secondary and tertiary crushers is achieved in a closed circuit crushing and screening plant. Screen products of minus 30 mm plus 6 mm lump, and minus 6 mm fines are stockpiled by conveyor and stacker systems prior to rail despatch 10 port facilities at Dampier. Crusher settings, determined from experience, are closely maintained to obtain the desired lump/fines ratio. Chemical and sizing analyses from automatically taken samples are used to maintain product specifications. The beneficiation plant upgrades the fines product when this is necessary. The recorded wear life of individual plant components is the basis of a planned maintenance programme.

Jan 1, 1970

By Glenn Norris, Tyler Buckingham

"Gold recovery gains in the order of one to two percent have been realized in 2009 due to changes in the operation of the grinding circuits at Barrick Gold Corporation’s Hemlo - Williams Mill. The initiative known as “split milling” involves milling low grade open pit ore in one grinding circuit and higher grade underground ore in the other grinding circuit under different conditions.The philosophy of split milling involves processing higher grade underground ore at a lower throughput rate and a finer grind while milling lower grade open pit ore at a higher throughput rate and a coarser grind. Bench scale tests showed that the recovery relationship for underground ore sources was much more grind sensitive than that of open pit ore. This relationship proved to hold in the plant. The gold recovery gain due to finer grinding of the higher grade ore is much greater than the recovery loss due to coarser grinding on the lower grade ore. Since the majority of gold is being recovered at a higher rate, this results in higher overall plant gold recovery when compared to the traditional operation philosophy of blending the ore sources.The challenges for achieving the maximum benefits of split milling were two fold; the need to increase throughput on the open pit ore milling circuit and a means of grinding finer on the underground circuit. The former was met with an increase in SAG (Semi-Autogenous Grinding) mill ball charge, a basic “drill to mill” blasting campaign and changes to the primary gyratory crusher. The latter was met with a reduced SAG mill ball charge and a higher milling density. The resulting benefits in additional gold recovered are in the order of $3-5 million per annum.INTRODUCTIONThe Williams Mill processes ore from three different ore sources, the David Bell Mine (DB), the Williams Underground Mine (WUG) and the Williams Open Pit (OP). All three ore sources are located within the Hemlo camp in Northwestern Ontario adjacent to the Trans-Canada Highway. The Williams Mill was built in the mid 1980’s at which time it was designed to process 3,000 dry metric tonnes per day through a 22’ SAG mill in series with a 16’ ball mill. In 1988 a Mill expansion doubled the mill capacity by adding a second identical grinding circuit. A photo of the current grinding circuit can be seen in Figure 1. Today the Williams Mill processes an average of 8,000 tonnes per day of which approximately 60% is from the Williams Open Pit."

Jan 1, 2010

Eco-Efficient Gravity Separation Solutions in India Sustainable development and social responsibility issues are a principal aspect of mineral processing operations around the world. With the need for more environmentally effective technologies, some gravity separation systems have provided eco-efficient mineral processing solutions in places where it is not otherwise viable because of lack of fresh water or for other environmental reasons. Advanced spiral separation technologies developed in Australia offer a cost effective and environmentally viable way to process minerals. In particular, we review recent case studies of spiral plants commissioned in India where environmentally sustainable solutions to design problems included the use of spirals operated with sea water and the use of high capacity (HC) spirals to provide low consumption of energy and materials and a reduced plant footprint. This paper evaluates the performance of various spiral plants in India and how critical environmental issues which affect the overall viability of wet concentrating processes where resolved.

Sep 13, 2010

Consents Required for Overseas Persons Overseas Investment Regulations 1974 Foreign investment proposals must be reviewed by the Overseas Investment Commission to ensure that these are in accord with national interests. Consent must be obtained from the Commission for: 1. New investment proposals which include: a. An overseas person acquiring 25 per cent or more of any class of share in a company. b. A New Zealand company issuing shares to an overseas person where this will result in that person owning 25 per cent or more of the company. c. An overseas person acquiring business assets for consideration in excess of $100 000. d. An overseas person commencing business in New Zealand. 2. Borrowing in New Zealand: An overseas person must obtain consent to raise funds in excess of $300 000 in New Zealand. 3. Borrowing Overseas: New Zealand incorporated companies must obtain consent to borrow overseas. Current policy is borrowing will be approved where the loan is for a specified fixed term of one year or more.

Jan 1, 1982

By Steve Kral

The mining industry has had three difficult years. Commodity prices have remained low and investor confidence in the industry has been shaken. And even though the Asian economy appears to be improving, it will be some time before this improvement will translate into better commodity price conditions for mining. In addition, increased environmental and social restrictions that have been placed on the industry in developed and developing countries have made mining a more difficult proposition. And, if that is not enough, the global mining industry has found itself in fierce competition with Internet businesses for investor capital. Despite that gloomy picture, more than 10,500 mining industry professionals from about 70 countries gathered in Toronto, Ontario March 5-10, 2000 for the Mining Millennium 2000 conference. This meeting was a joint effort between the Canadian Institute of Mining, Metallurgy and Petroleum(CIM) and the Prospectors and Developers Association of Canada (PDAC).The joint meeting also featured two trade exhibitions and more than 150speakers. PDAC’s trade show attracted about 400 exhibitors and an additional 200 in the concurrent Investors’ Exchange. CIM’s exhibition attracted about 600 equipment and service companies.

Jan 1, 2000

By E N. Sajin

The final arsenic bearing waste products at the majority of metallurgical and chemical enterprises are cakes in which arsenic is present in the form of calcium arsenate. Burial of cakes demands construction of special burial sites and does not guarantee reliable protection from arsenic penetration into the ground and surface waters. Under laboratory conditions we developed technology for processing calcium arsenate cakes with obtaining low toxic products suitable for long-term storage, meeting environmental requirements. The investigations have shown that thermal processing of briquetted mixtures of cakes containing 15 - 20 per cent weight of pyrite under the temperature of 873 - 923¦K during 45 - 60 minutes gives briquettes sufficiently hard for transportation and long-term storage. Arsenic, under high sulphidisation temperature is bonded into low solubility non-volatile iron sulphide bearing compounds having chemical properties similar to the natural arsenic compounds. Solubility of the obtained products in neutral, acid and alkaline media was investigated during long period of time (three to 12 months). It was determined that arsenic content in the solutions did not exceed the norms for cultural and welfare basins and fish-ponds.

Jan 1, 2002

By J. P. Welsh

Ground Modification construction is rapidly evolving in the United States. An assessment of the construction status of Ground Modification methods with their dates of introduction and general acceptance in the United States is summarized. Seven of these techniques are discussed in depth with short case histories; namely, Dynamic Deep Compaction, vibro-compaction, vibro-Replacement, chemical grouting, compaction grouting, slurry grouting and jet grouting. Additional case histories are presented to illustrate the trend of combining Ground Modification techniques to solve specific site problems.

Jan 1, 2010

By I. T. Oramah

Despite the abundance of solid mineral deposits, Nigeria only earns about 0.5-1% of its current Gross Domestic Product (GDP) from the solid minerals sector. This is as a result of the dominance of the oil and gas industry, which has negatively affected the competitiveness of other sectors of Nigeria’s economy. The dominance of this industry has resulted in unemployment, poverty, hunger, domestic price inflation, corruption, unstable government, and higher exchange rates. These impacts are typical for economies suffering from the effects of "Dutch Disease" and the "Resource Curse". Community-based small-scale mining offers hope as an economic activity that can create wealth, employment, reduce hunger and poverty, and provide basic amenities for rural communities with solid minerals endowment. This study presents preliminary results of ongoing research into the prospects of using community-based small-scale mining in a developing country like Nigeria to move towards rural sustainable development.

Jan 1, 2011

By Robert G. Lenz

Control of ground water for construction purposes is an everyday occurrence in the U.S. Thousands of pumps are in service at any given time. Most of these applications simply consist of pumping water out of an excavation, generally with the aid of sumps. Modern hydraulic and electric submersible pumps permit these procedures because of their ability to pump solids and take air without losing their prime. These procedures work fine up to a point and permit the contractor to control his ground water problems adequately and at minimal cost. When that point is exceeded, the ground water problems sometimes are compounded. Over-application of open pumping techniques can result in slope failures, cofferdam instability, bottom heaving, boils, loss of ground, damage to adjacent structures and utilities, and assorted other maladys which could and should be avoided. This paper will deal with the options involved in ground water control, a discussion of the unwanted side effects of dewatering, and examples of ground water control projects in various cities around the U.S.

Jan 1, 1988

By W. L. Jacobsen, T. L. Dyer

Cortez Gold Mines completed a feasibility study for a new openpit gold mine in north central Nevada. The production schedule calls for a peak in material movement. This schedule is based on current operational efficiencies and equipment parameters observed at the company’s existing openpit operation. To mitigate risks of over/under predicting production, simulation modeling was used to validate the loading and haulage requirements during the peak production period. The advantage of simulation is the ability to provide a realistic model of a mining operation based on scheduled and unscheduled random events during the period under analysis.

Jan 1, 2007

By H. F. Silliman, Daniel R. Hull, Earl W. Palmer

THE brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that [ ] contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6 ¾ in. wide by 1 in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. [ ] In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breaking rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause-however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By Tad Crowie, Victor Delgado, Nick Katsikaros, Tim Hughes

"A number of silver producers have identified a need for a system to recover silver and gold from base metal flotation concentrates on site rather than sending the concentrate to third party smelters to improve mine economics. Historically intensive cyanidation has only been used for coarse gold gravity concentrates in batch machines but Gekko have applied the InLine Leach Reactor (ILR) to these difficult to leach concentrates.The ILR’s unique ability to operate at various solid to solution ratios, high mass capacity, the ability to handle fines, the use of peroxide to aid silver leach kinetics and simple operation has resulted in significant economic benefits to Hochschild PLC’s Selene and Arcata operations. This paper describes the commissioning phase of the ILR5000BA intensive cyanidation reactors on concentrates from the Selene mine at the Ares Concentrator.INTRODUCTIONIntensive leaching of high grade concentrates in gold ore treatment is now commonplace and is considered an essential feature of most gold circuits (Lane, Fountain and LeBrooy, 2008). The devices commonly used for intensive leaching (InLine Leach Reactor, Acacia Reactor, etc) are specifically designed for the typical coarse nature of the concentrate.In some of these intensive leach applications, significant amounts of silver are co-recovered with the gold. In fact, the intensive leaching conditions of 1 to 2% NaCN in solution and high dissolved oxygen levels, overcome the issue with silver’s slow dissolution rate in traditional CIL/CIP circuits and avoids the formation of insoluble silver sulphide minerals on the surface of the gold (Marsden, 2006).There are a significant number of mine operators producing silver in the form of mixed base metal sulphides flotation concentrates. Typically the mine operators are paid for the silver after processing of the concentrate by the base metal smelter whom recovers the silver during the refining process."

Jan 1, 2010

By F. D. DeVaney

The low-grade deposits of manganese ores along the Missouri River near Chamberlain, S. Dak., are known to contain one of the largest reserves of manganese in the United States. Manganese occurs as concretionary nodules ranging in size from 13 inches in their longest dimension to particles finer than 65-mesh. The nodules are embedded in soft, wet shale, which contains little manganese. The removal of nodules from the low-grade shale is a simple mechanical problem; the question is primarily to determine the lowest-cost method of separation. This report purposes to present data acquired by experimenting with samples of the ore, which form a basis for suggesting methods of concentrating manganese nodules.

Jan 1, 1942

By F. D. DeVaney

The low-grade deposits of manganese ores along the Missouri River near Chamberlain, S. Dak., are known to contain one of the largest reserves of manganese in the United States. Manganese occurs as concretionary nodules ranging in size from 13 inches in their longest dimension to particles finer than 65-mesh. The nodules are embedded in soft, wet shale, which contains little manganese. The removal of nodules from the low-grade shale is a simple mechanical -problem; the question is primarily to determine the lowest-cost method of separation. This report purposes to present data acquired by experimenting with samples of the ore, which form a basis for suggesting methods of concentrating manganese nodules.

Jan 1, 1942

By Peter Ryan

A patented process for agglomeration of Smelter ESP dusts is described. Addition of suitable binders followed by compaction, transforms fine, difficult to handle material into a dry, flowable agglomerate suitable for plant reentry. Details for the agglomeration process metallurgy and laboratory pilot plant testing are discussed. An example of full scale plant operations is described.

Jan 1, 1999

By John K. Owens, Wayne L. Howie

Mobile roof support (MRS) machines are used as roof support during pillar recovery in retreat operations in lieu of wooden posts, cribs, or hydraulic props. A Mine Safety and Health Administration-permissible load rate monitoring system was developed for the MRS by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. The system uses a dedicated embedded processor to monitor changes in pressure inside the hydraulic cylinders of the MRS through multiplexed data acquisition channels and converts these pressure changes to load rates that sequentially activate three load-rate-indicator lights mounted on the machine. Each light represents a different loading rate to alert mine personnel to dangerous conditions during pillar extraction.

By N. Reddy

The influence of local geology and rock mass characteristics on deformations during a rockburst caused by a controlled blast was studied. This was done by means of visual examination, mapping and photography both before and after the blast. We found that the ejected material was bounded mostly by fractures associated with the bow-wave fracturing and bedding surfaces and that existed prior to the blast. Most of the damage was caused by shake-out. This information is important input for the design of rockburst resistant support systems under conditions of moderate stress.

Jan 1, 2001

By R. Armstrong, C. Ware, P. Sudan, G. Whitmore

The northern KwaZulu-Natal (KZN) coastal dune cordon, South Africa, extends from north of Durban into Mozambique. The Quaternary dune cordon, which can be up to 2 km wide, comprises a series of stacked, unconsolidated dunes that in places attain a height of over 100 m. Mining of the dunes produces much of the world’s supply of ilmenite, rutile and zircon. This paper documents the age of zircon grains separated from dune units, identifies likely source rocks and presents an evolutionary history for the dune cordon. Between 30 and 60 detrital zircon grains from three distinct units from the northern KZN coastal dunes were analysed for U/Pb isotopic ages using the SHRIMP II at the Australian National University. The samples represent units from the base (ca. 250 ka; luminescence age1),middle (ca. 190 ka2) and upper (ca. 20 ka2) portions of the coastal dune cordon. Zircon grain ages identify three source populations: (1) a 1 000 to 1 200 Ma group correlated to the Natal Metamorphic Province, (2) a 500 to 650 Ma group representing a Pan-African belt, which may correlate to the Mozambique Belt and (3) a ca. 650 to 800 Ma group of unknown provenance. Surprisingly, the presently exposed basement, comprising the Kaapvaal Craton and Archaean volcano-sedimentary sequences, has not supplied a significant amount of zircon grains (< 5%).This suggests that unroofing of basement rocks in the region has only occurred during the last 20ka. In addition, the absence of zircon grains younger than 500 Ma indicates that the bulk of zirconis not reworked from the Karoo Supergroup cover succession, but may be sourced by reworking of the Natal Group sandstones.

Jan 1, 2003

By Francis Kendorski

The Skyline #3 Mine of Canyon Fuel Company in Utah was planning longwall mine development adjacent to and downdip of older mine workings known to be flooded. Barrier pillar geometries and widths were proposed by mining company personnel. Hydraulic conductivity testing suggested that the general characteristics of the local coal seam, dikes, and faults are only weakly conductive and that leakage through the barriers, if any, would be minor. The mechanical performance of the proposed barrier pillar design was evaluated according to (1) published empirical design methods and (2) numerical stress modeling. Comparison of the proposed design, with the range of barrier widths derived from the empirical methods, served as a first-order check on the adequacy of the proposed design. Numerical modeling was used to evaluate conditions site-specific to the Skyline #3 Mine and barrier geometry. Models were developed to quantify the relationship between barrier width and the abutment stresses onto the future workings. The models were also used to estimate the stress distribution within the barrier pillars. The hydraulic performance of the proposed barrier pillar design was evaluated according to (1) published empirical design methods for hydraulic impoundments, (2) empirical method estimates of seepage through coal barrier pillars, (3) numerical hydrogeologic flow modeling, and (4) numerical strain modeling. Using the techniques described above, and based on relevant industry experience, underground observations, knowledge of local geologic conditions, hydrogeologic measurements, and analytical results, the level of geomechanical risk associated with the barrier design as proposed was considered low and the level of hydraulic risk was considered moderate. The largest uncertainty that remained was the possibility that unfavorable geologic structures, such as faults and dikes, would act as conduits for leakage of impounded water into the new workings. Although the study indicated only minor steady-state leakage would occur through a small number of known structures, the presence and full leakage potential of threatening structures in the barrier could not be reliably known until the barrier was mined. One longwall panel has been completed adjacent to the barrier with no evidence of water flow even in fractured zones. Thus, as predicted by the modeling and analysis, it appears that abutment stresses imparted on the barrier during mining did not substantially alter the natural hydrogeologic characteristics, or leakage potential, of the barrier. The longwall coal mine water-barrier pillar design and performance are considered a success.

Jan 1, 2007