Search Documents

By Charles J. Kucera

Today's highly publicized issues of resource development and environmental protection are not new. But recently these issues have been played one against the other, and some would have us believe they are mutually exclusive. Why? Because modern man has realized that the shortest route to achieving economic progress is to subdue nature. He extracts mineral resources from the earth to provide the raw materials upon which other processes and services are based. But often in his search for economic progress he finds that other highly- held values (e.g., an unspoiled environment) have been violated. The natural response is a counter action - to attempt to protect nature. But this response is basically unsatisfactory because it is reactive.

Jan 1, 1979

By WU Jian-hui

Keywords: metallic material; nickel powder; thermal decomposition; precursor; fibrillar powder; nanometer scale; passivation treatment The precursor thermal decomposition process of fibrillar nanometer scale nickel powder and passivation treatment of obtained powder are investigated, and the composition and morphology of the products are characterized by use of IR, TGA/DTA, XRD and SEM. The results show that the precursor morphology is a decisive factor to the product morphology of the nickel powder. The morphology of the product derived at low decomposing temperature is irregular. The nickel powders produced at the temperature higher than 480 coheres seriously. The product particles are reunited with the decomposition time prolong. The powder prepared under the optimal condition is fibrillar like woolen yarn; the grain diameter is less than 50nm.

Jan 1, 2005

By S. A. H Tyrrell, R. Rotzinger

"Taseko Mines Limited recommenced operation of the Gibraltar copper-molybdenum mine in 2004 and embarked on series of development projects to modernize the mine and increase throughput capacity. The Gibraltar Development Plan 3 (GDP3) project included a second stand-alone copper-molybdenum concentrator, a stand-alone molybdenum separation plant and associated services. Ausenco was contracted to commence the detailed design in 2Q2011, commissioning commenced in 4Q2012 and first ore was processed in 1Q2013. This paper discusses the design, implementation and commissioning of the GDP3 Concentrator.INTRODUCTION The Gibraltar Mine (Gibraltar) property is located in the Cariboo Region of south central British Columbia, approximately 360 kilometers northeast of Vancouver. The site is accessed via an 18 kilometer paved road from the town of McLeese Lake, which is located on the province’s main north-south highway between the cities of Williams Lake and Quesnel. Gibraltar was originally developed by Placer Development and commenced production in 1972. Gibraltar was acquired, while on care and maintenance, by Taseko Mines Limited (Taseko) in 1999 during a period of unusually low metal prices. Taseko recommenced operations at Gibraltar in 2004, and embarked on series of development projects to modernize the mine and increase throughput capacity. The 1972 Gibraltar process flowsheet incorporated two-stage crushing followed by rod and ball milling and flotation. In 2008 Gibraltar completed their first development stage that included the installation of a SAG mill, converting the existing rod mills to ball mills and adding additional flotation capacity. Gibraltar continued development with the installation of an in-pit primary crusher, expansion of the bulk regrind circuit, expansion of the cleaner flotation circuit, replacement of the tailings pumping system and replacement of the concentrate filters and dryer."

Jan 1, 2014

By D. R. Wilburn

This summary of international mineral exploration activities for 2008 draws upon available information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry, and presents analyses of exploration activities by the mineral industry based upon these data. Two types of information are reported and analyzed in this annual review of international exploration for 2008: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia (Metals Economics Group, 2008a, b), and 2) information on regional and site-specific exploration activities that took place in 2008 and compiled by the USGS. The MEG information summarizes planned company budgets for worldwide exploration activities in 2008, primarily for precious metals (gold, platinum-group metals and silver) and base metals (copper, lead, nickel and zinc). MEG includes information on additional mineral commodities only where it is available. Information on uranium exploration was included in the MEG overview for the first time in 2007, although this information was not included in the USGS analysis. The MEG survey methodology was changed in 1999 to include companies with exploration budgets between $100,000 and $2.9 million, as well as those companies included in prior studies whose anticipated budgets were above $2.9 million. MEG estimates that its post-1999 surveys cover at least 90 percent of world nonferrous nonfuel mineral exploration budgets. The 2008 survey is reported by MEG to cover an estimated 95 percent. Companies that chose not to participate in the MEG study, private companies that do not publish data, and government-funded exploration activities make up the majority of the remaining 5 percent. MEG included 91 more companies in its 2008 survey than it did in 2007 USGS compilations of site data described here primarily include nonfuel minerals, with an emphasis on base metals, diamond and precious metals. Analyses are based on information provided by USGS mineral commodity and country specialists and by other USGS scientists, as well as industry contacts and trade journals.

Jan 1, 2009

By T. A. Klinefelter

KYANITE and the related minerals sillimanite, andalusite, dumortierite, and topaz are natural aluminum silicates that can be used in production of mullite (3A1203?2Si02), a superduty refractory material. Kyanite and sillimanite are the dominant ones because of their greater abundance. The only other kyanite-group mineral presently used for mullite production is andalusite. Mullite is not an absolutely essential material as other refractories can be used in the same heat range. However, it is a highly satisfactory one. It is the only compound of silica and alumina that is stable at high temperatures. It has low thermal expansion and is very resistant to corrosive melts and to thermal shock. For these reasons mullite refractories have a much longer life than standard fire-clay refractories under the same conditions. Worldwide, excluding U.S.S.R., the refractories industry consumes about 150-000 short tons annually of kyanite group minerals and synthetic mullite.

Jan 1, 1961

THOSE who dabble in mining are no exception to the general rule that persons who know a little of a subject are apt to think that they know all about it. Some colour may be lent to the belief that anyone may succeed in mining when we hear stories ofsuccessful diggers and others who have accidentally dropped on to something good through no foresight on their part; but we seldom hear the contra account of the far larger number who fail. Those who go more thoroughly into the subject, and take up mining as a profession, know very well that it is not one that can be carried out successfully by rule of thumb, but when they point this out to the public they are credited with trying to make it a closed profession; and outsiders are for ever trying to find out the "trade secrets," at the same time spurning the main one, which is hard study, experience, and the ability to apply their knowledge. The average mining man is not rich. When he amasses a fortune it is generally through speculation rather than professional work, thought no doubt his technical knowledge may have assisted...

Jan 1, 1910

By P. den Hoed, R. I. Rambiyana

"Four sulphide minerals - pyrite (FeS2), pyrrhotite (Fe1-xS), pentlandite ([Ni,Fe]9S8), and chalcopyrite (CuFeS2) - contain the base metals and most of the iron in concentrates of platinum group metals (PGMs). In the pyrometallurgical processing of PGM concentrates these sulphides form a matte during smelting, and iron and sulphur are removed from the matte during the converting process. This paper discusses the roasting of Merensky concentrate in air before smelting, with the purpose of reducing the matte load to the converter.Roasting tests were conducted in a bench-scale rotary kiln at temperatures from 350°C to 700°C. The concentrate tested contained 17.4% sulphur and consisted of 23% pyrrhotite, 16% pentlandite, 11% chalcopyrite, and 2% pyrite. The particles were fine (d50 = 22 µm), and all the sulphide particles were liberated. Roasting in air at 550°C and 650°C for 20 minutes removed respectively 60% and 70% of the sulphur. The iron in the sulphides was oxidized to Fe3O4 (magnetite) at temperatures below 500°C and to Fe2O3 (haematite) at temperatures above 550°C. At 700°C the bed sintered and copper oxides formed. At temperatures below 450°C oxidation was incomplete: pyrrhotite remained and only 30% of the sulphur was removed. Smelting tests were conducted to assess matte fall and the deportment of copper and nickel to matte. It was evident that roasting resulted in lower matte falls (a drop of approximately 60%) compared with matte falls from unroasted concentrate. The iron and sulphur levels in the matte were reduced to below 3.5% and 22% respectively.This paper also briefly describes the mechanisms by which pyrrhotite, chalcopyrite, and pentlandite are oxidized during roasting. For chalcopyrite, the mechanism proceeds through an intermediate solid solution phase, which extends from Cu1.02Fe1.04S2 to Cu2.04Fe0.72S2 to a copper-rich solid solution of bornite (Cu4Fe1.4S4-Cu2S). The oxidation of pentlandite proceeds through a monosulphide solid solution (Ni0.39Fe0.53S-Ni0.74Fe0.15S) to a solid solution of heazlewoodite ([Ni,Fe]3}xS2). These mechanisms are explored in relation to chemical thermodynamics and microstructures."

Jan 1, 2015

By Dave Capstick, Ken Garner, Jim Porter

Technologies and systems used in the management of energy consumption in the mining and metal processing industry are well understood and documented from the supply side of the business. It is our contention that in many instances, through a more complete understanding of the demand side of the business, based on the detail of the operations plan, will provide greater lead time in terms of the design, implementation and utilisation of power supply infrastructure. Thus, optimal management of demand in a proactive manner, based on production requirements, will ensure both security of supply as well as continuity of operations. This paper describes the technology and methodology that is being developed to enable the above statement to be achieved. We use a case study to demonstrate the ability of the tools and methodology and conclude by outlining the business benefits achievable as well as the future developments emanating from this initiative.

Jan 1, 2005

By Robert E. Wood

The temperature dependency of the low-density viscosity coefficients, ?°T, of helium and of nitrogen, 100° to 1,000° K, is correlated with empirical equations, and the temperature and composition dependencies of the low-density viscosity coefficients, ?°T, of helium-nitrogen mixtures are correlated with the Chapman-Enskog expressions by using the Lennard-Jones (6:12) potential function. The residual viscosity, ?T,P - ?°T (the difference between the viscosity of a compressed gas and the dilute gas at a given temperature), was found to be a function of the thermal pressure coefficient, (?P/?T)V, and two parameters, a and 1, which are characteristic of gas composition. The equation ?T, P = ?°T + a [(?P/?T)V]ß represented 1,340 higher pressure experimental viscosity values with a mean absolute deviation of 0.86 percent, and this equation was used to compute viscosities of the gaseous helium-nitrogen system for a range of temperatures and pressures including those encountered in Bureau of Mines helium purification processes and in a crude-helium conservation gas reservoir. Tabular viscosities for helium, nitrogen, and 13 helium-nitrogen mixtures are presented for 110 temperatures, 133° to 740' K, and 49 pressures in the range 1 to 240 atmospheres. The accuracy of the tabulated viscosities varies because correlation parameters were obtained from experimental data of unequal reliability. It is estimated that uncertainties in the computed viscosity values are ±5 percent for the region 325° to 740° K, ±2 percent for the region 183° to 325° K, and ±5 percent for temperatures below 183° K. The latter uncertainty may rise to y10 percent as critical conditions are approached.

Jan 1, 1970

DML Resources Limited - Mining Division produced over 50 000 oz of alluvial gold in the 1995 - 1996 year from five operations located in the West Coast and Otago Regions on the South Island of New Zealand. DML Resources Limited - Mining Division have a twenty year history of alluvial gold mining development in New Zealand. Recent expansions have seen the establishment of two operations in Chile whilst exploration continues in Bolivia, Peru and Argentina. The overseas growth is based on a stable production base in New Zealand focussed on the West Coast and Southland/Otago present and future operations. DML Resources consider that the mining potential in the Arahura Valley on the West coast will be fundamental to their New Zealand operations for some time. Collectively the plants operating in this catchment are referred to as the Poutini Project. Recent and late Pleistocene gravels derived from the erosion of the Alpine Schists running parallel to the Alpine Fault located on the Pacific/Australian Plant boundary are thought to be the sources of the alluvial gold in the Arahura and adjacent catchments. These gravels have been extensively mined for the past 130 years yielding some six million ounces over this period. Production from the Poutini Project started in 1989 and stood at approximately 35 000 oz for the 1995 - 1996 year. This production was split among three plants each working different areas of the deposit. Recovery techniques from each of the plants are fundamentally the same. Gravels are fed to a floating treatment plant where, following screening, the gold is recovered using jig plants and knudsen bowls. Overburden to wash stripping ratios vary between zero and seven to one with plants treating between 80 and 250 cubic metres per hour. Restoration of the land following mining is undertaken progressively. All land in the Poutini Project area mined to date has been restored to a standard suitable for dairy farming purposes. The Poutini Project is a cooperative venture between the Maori landowners and DML Resources Ltd. The Arahura River has particular cultural significance to the Maori as it is the source of the much valued greenstone or pounamu a type of jade valued for jewellery and tools. The Poutini Agreement was signed in 1989 setting out the role of each party in the mining of the Arahura and adjacent lands. Current exploration and development should extend the resource to allow mining to continue on the Poutini project for an additional three to five years at current gold prices. Production within new Zealand beyond this point may be compromised by increasing difficulty in gaining access to prospective areas within New Zealand, lowered margins due to high New Zealand dollar exchange rates and the overall lowering of alluvial headgrades throughout the West Coast and Otago/Southland regions. To counter these effects DML has continued to improve on operational efficiency and performance monitoring to optimise the mining practices used. This paper detains the background to the Poutini Project, the geology, plant and equipment used together with descriptions of the current mining methods employed.

Jan 1, 1996

By John C. Stankus

To improve mine roof bolt performance, Jennmar Corporation commenced the design and development of a new roof control sys- tem. This new system designated "Insta'l Compression", not only improves safety, but is more cost efficient due to reduced amounts of resin needed per bolt installation. In this paper the research and development of this new system will be outlined. Much of the information presented will be actual test data from various underground operations in Alabama, Kentucky, and Pennsylvania. The development of this system will also cover the design of a new expansion shell, resin compression ring, anti- friction washer, and upgrading of material specifications.

Jan 1, 1990

By Briony C. Ruse, David V. Boger, Fiona Sofra1

"The sustainability of the mining industry must be addressed through improving tailings management. The use of thickened tailings and pastes stems from a paradigm shift towards designing tailings disposal sites to suit their surrounding environment, rather than manipulating the environment to accommodate the tailings. Thickened tailings and pastes usually exhibit non-Newtonian behaviour, so a thorough understanding of the rheological characteristics of the material is required in order to determine the disposal plant operating conditions.As environmental factors translate into economic issues, minimising waste production using dry disposal methods is gaining popularity. The use of rheological information is of high importance in evaluating the spreading characteristics, the transportation and the dewatering of thickened mineral tailings. The principles outlined may be applied to many industries encompassing a wide range of waste materials. The main obstacle to the widespread implementation of dry disposal methods has been the high initial capital cost of the methods due to the dewatering step, and the high cost of pumping thick suspensions across any great distance. Proper and thorough costing of tailings disposal activities combined with an accounting approach that shows closure and post-closure care costs on a per tonne basis of tailings disposed throughout the life of the tailings facility will show that dry disposal methods are more favourable than they might seem on initial appraisal."

Jan 1, 2003

A new lead refinery with a capacity of 230,000 tons per year commenced operation at Port Pirie in October, 1959. This plant superseded the refinery which had operated from 1933 with the advent of the continuous lead refining process. The incorporation of new equipment following local metallurgical developments, together with the overseas demand for lead of extremely low antimony content createddifficulties in operating the original plant. The new refinery project was undertaken to cover this disability and to gain the full advantage of the new processes.Desilverising and softening are carried out in units identical in size to those used previously. Metallic zinc is recovered from the entire output of desilverised bullion by vacuum distillation. Final refining is carried out by batch treatment with caustic soda yielding lead of purity previously unattainable at Port Pirie.These two processes replace continuous dezincing by oxidation, a high temperature process which caused large quantities of lead and antimony to be recirculated. The final stage is a batch process; therefore the product composition can be checked before casting. Individual batches can be adjusted to produce special alloys to consumer's specification.Improved casting equipment allows the quantity production of pigs of good physical characteristics either as 56 lb bars or 2000 lb pigs.This, together with the high purity of the lead, assures the Broken Hill Associated Smelters Pty. Ltd. (RH.A.S.) position in world markets.Automatic control systems are extensively employed, particularly on the vacuum dezincing unit.The anticipated financial benefits have been achieved mainly by a reduction in the tonnage of recirculated materials, a smaller labour force, and reduced maintenance requirements.INTRODUCTIONIn December 1956 a decision was made to build at Port Pirie a lead refinery on a completely new site, and in October 1959 the new refinery was brought into operation. This plant superseded the lead section of the old refinery which...

Jan 1, 1963

Removal of Arsenic in Fluorite Ore by Simultaneous Grinding-Leaching with NaHS Generally speaking, a high-grade fluorite ore is converted into hydrogen fluoride (HF), which is essential for the semiconductor manufacturing. With the continuous depletion of resources, novel technologies for processing low-grade fluorite ores are urgently needed, in order to lower the arsenic concentration to less than 100 mg/kg. In this study, a low-grade fluorite ore was upgraded by removing arsenic, which is difficult to remove by conventional method. The mechano-chemical leaching of fluorite ore (i.e. the sample was ground in presence of NaHS, using a beads mill) was carried out to investigate the removal of arsenic from the low-grade fluorite. Experimental results showed that the arsenic concentration was reduced to 73.2 mg/kg.

Sep 13, 2010

By W. R. K. Wu

Results of linear correlations of two to four variables by the least-squares method are presented. The variables include 63 parameters representing coal composition, coal plasticity, and coke strength. The composition parameters are on chemical analyses; the plasticity parameters, on three plastometer and dilatometer tests and four miscellaneous tests; and the coke-strength parameters, on three ASTM indices. Seventy-two to eighty-four plastic coals were used in the plasticity and carbonization tests, which together form the basis of this report; 43 nonplastic or weakly plastic coals were used in the coal-band studies. Plots of relations between volatile matter, carbon, and oxygen contents of 1,860 U.S. coals and the 84 coals used are shown. Similar plots between volatile matter and hydrogen or atomic H/C of the 84 coals are also included. Significances of regression coefficient signs for coal composition parameters in the significant correlations found are discussed. Based on these significances, the following relations are shown: (a) coke strength versus average aromaticity, or mineral matter content, of the parent coal; (b) characteristic temperatures of the plastometer and dilatometers, the free-swelling index, or the Gray-King type versus average hydroaromaticity of the coal; and (c) nontemperature parameters of the plastometer and dilatometers versus the physical properties of a certain group of compounds from thermal decomposition of coal. Similarly, significances between the positions of coals in the coal band and the aforementioned relations are also discussed. A structural theory of coal plasticity is proposed. Applications of the correlation results are discussed. Composition parameters, such as carbon, atomic H/C, and calorific value may be used as a basis for selecting coking coals for stronger coke. Plasticity parameters, such as the end temperatures of the plastometer and dilatometers and the free-swelling index, may be used for the same purpose. Based on the best correlations found, coke-strength indices may be estimated to within 4 to 8 units of the observed values; the end temperatures of the plastometer and dilatometer tests, 5° to 10° C.; and the free-swelling index, within 1 unit. Accuracies of all these estimated values are examined, based on the experimental errors of the data involved. Finally, estimations of plasticity parameters from one test with those from others are shown.

Jan 1, 1971

By Edward J. Caldwell

In 1930 the Bureau of Mines published a description3/ f the concentrating process of the Magma Copper Co. as it had been developed to that time and was then employed. The prevent paper revises the description to the end of 1943 and includes a description of the smelting processes. Data from the mild and smelter operations for, 1942 are given in tables 1 to 14, Billing costs are included, but it is not permissible to publish smelter costs.

Jan 1, 1944

By P. H. Morris

Nineteen field trials of the co-disposal of fine coal tailings and coarse coal wastes were conducted at the dual Goonyella-Riverside mine in Queensland and at the Hunter Valley No. 1 and Warkworth mines in New South Wales, Australia. The profiles of and the sorting that occurred on the co-disposal deltas are described and an existing theory of subaerial deposition, originally developed for mine tailings alone, is shown to apply to the co-disposed wastes. This enables the dimensionless profiles of large deltas, which may take years to deposit, to be predicted from data obtained from a small delta formed in a few days or even hours

Jun 19, 1905

By Werner Burger

Earth Pressure tunnel boring machines are tackling difficult ground conditions that five years previous were not considered feasible. The technology has evolved that allows EPB TBMs to cross into areas that with the latest in conditioning and special design considerations are now possible to mine. This paper will review the various recent developments and those projects where these new techniques have been applied.

Jan 1, 2008

By E. L. Litchfield

The electrification of ammonium nitrate-fuel oil (AN-FO) blasting agents by pneumatic loaders is described and discussed. The consequences of the electrification are considered in light of the initiation requirements of electric blasting caps. It is recommended (1) that semiconductive loading tubing be utilized and (2) that the resistivity of the AN-FO be controlled; it is further recommended that the operator (3) test to assure continuity of the electric detonator legwire-bridgewire-legwire circuit prior to insertion of the cap into charge or borehole, (4) keep the legwires shunted but not otherwise connected to ground during loading of the blasting agent into the borehole, (5) assure that the borehole is discharged prior to hooking up the detonator leads, (6) assure that he is himself discharged prior to handling the detonator leads, and (7) assure that the blasting cap leads are never carried to the AN-FO loader. The basis and significance of these recommendations are explained.

Jan 1, 1968

Great new drilling results! What's so sinful about being a multi-national company? Overseas protestors flown to Australia for a free holiday How to counter the protectionist danger? Our current economic standing Over-regulation puts a convicted paedophile on the payroll The broken window fallacy Mining - A shared history Aristotle and the camels A brighter future? Something over which we do have far greater control, i.e. leadership within our own industry My challenge to you The expanding gold- producing company of which I am proud to be Chairman, Croesus Mining NL, is by definition a æmultinationalÆ. Our shareholders are based in 36 different countries, 77% of our 107 million shares are held in Australia, 23% are held outside Australia, and include New Zealand holdings of 7%. In September, Croesus Mining presented our company at the Mining 2000 Forum in Melbourne, a city caught up with multinational protestors demonstrating against multi-national companies.  

Jan 1, 2000