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By W. L. Murphy

The Star Lake property, located 115 km northeast of La Ronge, Saskatchewan is underlain by metamorphosed andesitic tuffs and flows which have been intruded by the dioritic to granitic Star Lake Pluton. Gold mineralization on the Star Lake property was first discovered at Ru h Lake by E. Beveridge in 1959 and by M. and E. Hird in 1961. In 1960 E. Partridge discovered Kahn 18 and Kahn 28. In 1982 the SMDC-Starrex joint venture completed geophysical and geochemical urveys including magnetics, VLF, IP/Resistivity, vegetation, bulk till and oil sampling, followed by drill testing of pecific targets. To date the most ignificant depo it is the 21 Zone which contain drill indicated reserves of 230,000 tons grading 0.5 oz/ton Au . The 21 Zone con ists of quartz with 5-10% (locally > 30%) drusy pyrite, minor chalcopyrite and trace amounts of scheelite, chalcocite and arsenopyrite. The 21 Zone is enclosed by a 25-50 m wide band of mylonitized monzonite. The mylonite occurs in the central portion of a 300 m wide northeasterly trending zone of brittle deformation .

Jan 1, 1986

By Joseph P. DuCarme

The U.S. Bureau of Mines explored new methods and technology for extracting coal from the Appalachian Mountain region of the Eastern United States. These methods were aimed at extracting coal from thin seams and focused on the use of "roof-fall-tolerant" (RFT) mining concepts. These methods could be used on existing, abandoned highwalls or in conjunction with new highwall mining. The research was conducted using small-scale and quasi-full-scale physical models to obtain experimental results. Details are provided on (1) the quasi-full-scale model for cross-ridge mining, (2) the quasi-full-scale model for down-ridge mining, (3) the test results of these models, and (4) recommendations for future research. Significant results include demonstration of the RFT concept, a discussion of expected coal produced from these methods, and recommendations for future research.

Jan 1, 2010

By L. Holappa

Ferroalloys like FeCr and FeMn are mostly produced in submerged electric arc furnaces. Typical of these processes is that the amount of slag is quite high. The role of slag for the process is thus essential and specific chemical, physical and electrical properties are required. Slags in FeCr process are Al2O3-MgO-SiO2 based with minor contents of CaO and CrOx. Slags in the FeMn process are principally similar, originating from silicate minerals but can have quite large composition range depending on the manganese ore and its gangue minerals. Characteristic of the FeMn process is that the slag is rich in manganese oxide up to above 30%. A common feature is that the ?ore oxides?, CrOx and MnOx in slag are not only divalent oxides but also contain some higher valent of Cr3+and Mn3+, respectively. In FeMn production conditions the slag consists mainly of Mn2+. This is a clear difference from CrOx containing slags in which both two and three valent coexist in slags in FeCr process conditions. Oxidation state of the slag depends on the ambient oxygen partial pressure and temperature in the examined process. The thermodynamics of slags in ferroalloys, production are discussed in terms of phase diagrams, activities and oxidation state of chromium and manganese oxides. Further, slag properties influencing reduction kinetics and furnace operation i.e. viscosity and electrical resistivity are discussed. Keywords: review, slags, ferroalloys, ferrochromium, ferromanganese, thermodynamics, physical properties

Jan 1, 2004

Treatment of the Siirt-Madenk÷y Ores by Flotation

Sep 13, 2010

By Michelle Mouton, Johanna van Deventer, Jussi Vaarno

Mintek has been involved in numerous projects to remove Fe and Mn from dilute Co sulphate solutions by means of oxidative precipitation using air/SO2. Test work was done using a gas induction system, designed and supplied by Outotec. Various aspects, such as SO2 concentration, SO2 flowrate, impeller rotation speed and pH were investigated on a 2 m3 scale. Batch tests were performed using a residence time of 5 hours. Mintek has been involved in numerous projects to remove Fe and Mn from dilute Co sulphate solutions by means of oxidative precipitation using air/SO2. Test work was done using a gas induction system, designed and supplied by Outotec. Various aspects, such as SO2 concentration, SO2 flowrate, impeller rotation speed and pH were investigated on a 2 m3 scale. Batch tests were performed using a residence time of 5 hours. Impeller rotation speeds of 0-220 rpm were tested, and it seemed that speeds of between 80 and 220 rpm gave similar Fe and Mn removal rates. Co and Cu losses were generally below 1% and 5% respectively at pH 3.

Jan 1, 2007

By H. Robert Ensminger

The Belizean economy registered a modest real growth of 1.3% during 1981. The gross domestic product (GDP), based on current prim was $121 million' with an inflation-rate of 10%. The country received $19 million in economic aid during 1981. In early 1981, Belize'e four commercial banks raised the interest on deposits to 15% in an effort to curb capital outflow. During 1981, the financial situation deteriorated somewhat, particularly the balance of payments. For the year the total value of imports exceeded exports by almost $38 million, while the Government continued to maintain a fairly free trade policy. Import duties and term averaged about 8% on essential item and 40% on nonessential ones.

Jan 1, 1983

By Karl J. C. Harries

"8.1. INTRODUCTIONThe purpose of this chapter is not to provide precedents or examples of provisions, but rather to offer some comments that may be worth considering in the negotiation or review of an agreement. These comments are not intended to be exhaustive. It must also be noted that, although the chapter is written in the context of a common law joint venture, the concepts and concerns for the most part apply equally to a corporation that is owned by only a few shareholders for the purpose of participating in the project held by the corporation.The corporation has the advantage of having much of its organization established by local corporate law, but the particular wishes of the shareholders will appear in a shareholders’ agreement. The principal differences will be surprisingly small, save for the acquisition provisions that appear in a farm-in agreement1 and the substantial portion of the joint venture agreement devoted to creating and organizing the joint venture entity. Where the joint venture agreement refers to venturers and committees, the shareholders’ agreement will refer to shareholders and the board of directors, but both will have to deal with such basic matters as decision-making, default, dispute resolution, first refusals, funding, and carrying out work on the project. For convenience, this chapter usually refers to “venturers”, which may be taken to include shareholders.Negotiations give rise to many varying circumstances and concerns, and the main asset of the negotiator is an open and flexible mind. A desired result can often be accomplished indirectly in circumstances where the other side has adopted an inflexible position on a suggested approach. As precedents and standard forms tend to focus a negotiator’s thinking, they can be counterproductive. It is after the deal has been agreed to that a precedent can be of great assistance to the draftsman.The concepts are arranged in alphabetical order for convenience, not to suggest their sequence or position in an agreement or their relative importance. An agreement should adopt a progression of subjects in what the parties consider a logical sequence to read and work with. However, experience has indicated that it is best to set out in a single article the substance of the deal (i.e. the terms relating to the farm-in and what the acquiring party has to do to acquire his interest), preferably near the beginning of an agreement. The acquisition of the interest is, after all, the first order of business. The joint venture provisions will then follow in a reasonable sequence. It is also worthwhile to devote a single article to any special provisions that may apply during the earn-in period. For example, it may be provided that, although all work is to be done by the acquiring party as operator (with the duty of care, liability, and reporting requirements as set out in the joint venture sections of the agreement), but during the acquisition period, the acquiring party, acting as operator, may be at liberty to do such work as he wishes, without the need for any committee or other approvals, and committee meetings may be suspended.2An agreement is divided into paragraphs and articles to make it easier for the parties to read and understand, and to assist a party in finding “that provision” when the need arises. A comprehensive table of contents will also assist the parties who must work under an agreement. An added benefit of a table of contents is that in preparing it, the draftsman sees the overall structure of the agreement and will often catch and correct flaws."

Jan 1, 2003

By D. Rutledge

Discrete (digital) signal processing techniques are proving to be very valuable tools for miners using the block cave method. Waveform analysis of different measured signals associated with active mining provides valuable information on production dynamics and safe operation of the mine. For example, correlation of the 3D surface displacement velocity waveform and the production output waveform reveals a remarkably predictable time-varying physical process. Studying the geometrical and temporal relationship between these two signals opens a broad window through which new management techniques become apparent. In this paper we discuss the signal processing techniques used to study these relationships, as well as the related implications for mining. This research was carried out in association with the Chevron Mining underground molybdenum mine in Questa, New Mexico. Some of these new techniques will be integrated into the decision management process at the mine and will provide insight on ore production, draw control, and safe reclamation. The science of signal processing involves the analysis and interpretation of physical processes that vary with time. Two general categories of signals1 are recognized. A continuous signal is a waveform of varying amplitude that is continuous in time (such as a sine wave). A discrete signal is a sequence of quantized values. The independent time variable and amplitude are sampled periodically such that we only know the value and shape of the waveform at the sampling frequency. Displacements measured by a Global Positioning System (GPS) receiver are an example of this. Discrete signals may be studied in the time, frequency, autocorrelation, or wavelet domains. In this paper the amount of ore extracted from the mine and the measured surface displacements are analyzed in the time domain.

Jan 1, 2008

In a gravity separation device, particle shape, size and density all play a role. The combination of these determines where each individual particle reports to in the viscous fluid, where particle crowding (solids to water ratio) also plays a role. To understand the performance of gravity separation devices in the heavy mineral industry, these particle characteristics need to be measured. There are various challenges in analysing particle density and particle size simultaneously for the purpose of quantifying gravity separator performance, not to mention particle shape. These analytical challenges include the high cost of high-density sink-float fractionation, toxicity of high-density sink-float media, inability of sink-float media to fractionate at densities greater than 4.0 g/cm3, and the time-intensive nature of these fractionations. The use of the detailed particle-by-particle output from Qemscan® particle mineral analyses (PMA) as a fast and cost-effective alternative is evaluated. The size and density outputs from the Qemscan® were employed to characterize the performance of a heavy mineral spiral concentrator as an example. Critical analytical requirements are to be addressed before the Qemscan® output data can be utilized. Keywords Gravity separator, performance, heavy minerals, Qemscan® particle mineral analysis

Jan 1, 2011

By Graham Davey

"Ultrafine grinding of minerals has been in wide spread use in the industrial mineral field for over 30 years. Within the last 10 years the metalliferous industry has shown interest in the ability to produce ultrafine particles, as chemical, physio-chemical and physical separation processes have advanced to be able to treat ultrafine metalliferous particles. Also as the primary mineral deposits are depleted, new more difficult deposits must be mined. Existing operations are also looking to maximize economic return from existing deposits, requiring new thinking and technologies.The recent development of industrially proven and cost efficient technologies for ultrafine grinding has opened up another processing option for the treatment of finegrained metalliferous and refractory gold ores. The current commercial designs are variations of stirred mills used in the industrial minerals sector for the past 30 years. For the purposes of this paper ultrafine grinding is considered to be P80 of less than 15 microns.Attrition milling to fine grind sizes presents some challenging issues relating to scale-up including the dearth of information on the quantitative impact of feed and operating conditions, as well as the precise and accurate measurement of particle size distributions. Two examples from recent installations will be analyzed including Thalanga Copper and Century Zinc Mines. Both have diverse grind size targets for the SMD, yet both have realized significant metallurgical gains."

Jan 1, 2002

The geologist is often called upon to give judgment on the possibilities of reviving a former mining field presumably worked out as far as the evidence then available indicated. From time to time, scarcity and consequent high prices of metals has led to there-examination of many old fields. The possibility of resuming investigation on them where the practical miner ceased work, even where he had the aid of the trained geologist, has long since disappeared.Means of access to mines have been removed and water fills the workings. Hence an indirect mode of attack becomes essential.This method depends mainly on past history, and may be described as a reaching out by faith supported by shrewd guessing from the known to the unknown. Apart from whatever general intelligent observations may be made in situ of the evidence of former mining activity, the method depends largely on the examination of the past history of the field as revealed in the official records, company reports, plans of underground workings, local newspaper accounts, and the testimony of practical miners formerly employedon the field, the' reliability of which has to be carefully sifted. The matter derived from the examination of these sources must next be rigorously collated and correlated where possible. When the review of all individu!1l features and aspects has been completed, tentative and speculative conclusions may be drawn which, though not verifiable before the event, will usually prove to be more serviceable guides in exploratory operations than mere "blind stabbing."As an actual illustration of what is involved in the mode of procedure outlined above, the following is the description of an investigation in which the writer took part.In 1937, during the course of the Commonwealth Aerial, Geological and Geophysical Survey of Northern Australia, a detailed geological investigation was undertaken of the Croydon gold field, situated near the south-eastern. extremity of the Gulf of Carpentaria in North Queensland.The history of the field briefly is as follows: It was discovered in 1885, reached its peak of production 1896, declining thereafter till 1906, when operations ceased. The total production was about 1,000,000 ounces of gold bullion, containing approximately 40 per cent. of silver. The gold bullion was won from flat-dipping quartz reefs, which yielded an average of 2.oz. to the ton, and the maximum depth to which production occurred was 500 feet. Subsequent prospecting below this depth failed to locate further ore.In consequence of the inaccessibility of the mines and the almost total masking of the' surface by alluvium, the investigation of future possibilities became largely an. office ,study, which was conducted under the following headings:-1. Recording of factual data of each mine separately.

Jan 1, 1950

This modern plant was installed with the object of treating all oxide ore and payable dump material by the cyanide process.The plant is located on a ridge on the eastern side of Linda Gully. The mill -site has a slope to the south of 1 in 4.The new plant is of steel and concrete construction and was specially designed to suit the climatic conditions which exist at Mount Morgan.THE COARSE CRUSHING PLANTThe ore received from the, mine is dumped into a 600-ton steel bin which is commanded by a 3 ft. 6 in. gauge railway,The mine ore is conveyed by steam locomotives in rakes of five self-dumping 7-ton railroad cars. The dump material is mostly loaded by bull-dozers and conveyed to the binsin large motor lorries. Located on the top of the bin is a heavy railroad grizzly having 12-in openings through which all ore must pass.The flow of ore from this steel bin is controlled by a No. 7D 3-speed Ross chain feeder. It should be mentioned here that, although the bottom of the steel bin is inclined at an angle of 45°, it has been found, owing to the clayey nature of the oxide ore, that the live capacity of the bin is only about 50% of the total capacity.

Jan 1, 1939

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

Cyanidation processes for the extraction of gold or silver frequently involve the processing of sulfur-containing solids which 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 which involve the processing of sulfide ores or concentrates or which utilize a biological sulfur oxidation process, more attention has been focused on minimizing thiocyanate formation and in treating solutions to eliminate toxicity associated with thiocyanate. Though not yet commercially applied, there are several technologies available to recover cyanide from thiocyanate to both reduce tailings toxicity and allow the reuse of cyanide otherwise lost to thiocyanate formation. This paper presents an overview of technologies available for recovering cyanide from thiocyanate along with estimated operating costs for the technologies. 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, 2000

By Pilon CG, Deakin RC

It is proposed that a waste rock dump be constructed on slopes consisting of soft colluvium and weathered Chim Formation mudstone at the Porgera Gold Mine, in Enga Province, Papua New Guinea (PNG). Geolog- ical, geomorphological and geophysical investigations were conducted in support of geotechnical studies to assess the physical character of the 6km2 site. Geomorphological studies focused on the extent and nature of colluvium cover and landslide activity. Detailed ground traverse mapping resulted in classification and delineation of eight terrains and seven material types. Seismic refraction and resistivity profiling, combined with drilling, provided subsurface data. Results were presented as standard profiles, coloured contoured sections and plans. Subsurface features, including deep colluvial channels, buried cliffs, slump blocks and buried alluvial channels, were identified. Results of the combined investigations allowed designers to model the colluvium/ bedrock surface and identify critical areas of deep, mobile colluvium and weak bedrock. A design approach was developed which accounted for the morphology of landslide systems and distribution of colluvium types.

Jan 1, 1991

By W. Dziurzynski

Transient states of the air parameters in mine workings occur as the effects of natural and technological disturbances, and in particular as a result of changes in ventilation conditions, caused by alteration of the mine workings geometry, state of fans performance or emission of gases. Particularly significant are those transient states caused by disturbances resulted from catastrophes, since they are frequently associated with violent phenomena that may be a danger for life and health of the staff working underground. The paper presents a number of examples of transient states of the air parameters in mine workings after a catastrophe, like the bump in the ZABRZE-BIELSZOWICE coal mine. Registration of air disturbances by the monitoring systems of ventilation in mine workings in the area of disaster both at the moment of a catastrophe occurrence and later during the rescue operation, enabled to track out the incident and identify the circumstances and reasons of those tragic events which caused death of 18 miners during last two years. Furthermore, computer simulations of processes occurring in mine ventilation network make effective research tools to be applied in practice, among others for the study of accidents and disasters.

Jan 1, 2003

By Mark R. Svinkin

This paper deals with application of the wave equation analysis to determine capacities of piles driven in saturated sandy soils. It shows that pile capacity in sandy soils changes with time after the completion of pile driving and depends on the ground water elevation. In saturated sandy soils the setup coefficient ranges between upper and lower curves represented by power functions. For a reliable prediction of pile capacity wave equation input should be adjusted with soil damping. Back calculation of soil damping from known pile capacity performed for five tested piles shows that skin damping coefficient changes with time in the same manner as the pile capacity and can be represented by the power functions for considered damping models.

Jan 1, 1995

By Wylie A. W, Mathew P. J, Eisler P. L

Field studies of the radiations backscattered by iron ores from a 60Co source of primary gamma radiation located in a borehole logging probe have confirmed thatthe P" factor, a ratio of high energy gamma ray intensities to low energy intensities in selected energy windows of the backscattered gamma-ray spectrum, is a valuable measure of grade for sedimentary iron ores of the Pilbararegion of Western Australia.Laboratory studies of model boreholes have shown that variations in borehole diameter and variations in bulk density of the formations have a significant influence on the measurement of P" ratios. If these influences 'are taken into account the mean ore grade in a new blast hole, for instance, can be predicted with a probe of suitable configuration to within 0·8 per cent Fe at the 95 per cent confidence level, while the grade of a single 120-cm split can be determined to within 2·6 per cent Fe. These results were obtained by pooling data from five blast holes covering the range of iron concentrations 20-68 per cent Fe and apply to the mean hole grades 54-68 per cent Fe.Results for two development holes were generally comparable to those obtained from individual blast holes95 per cent confidence limits of ±0·9 per cent Fe for mean ore grade and ± 4·1 per cent Fe for single splits. A greater number of data points is needed before these confidence limits can be further improved.The technique utilized to obtain these results was derived from a "multiband" approach to collection of backscattered spectral intensity data, an approach which permitted selection at the data processing stage of the most statistically significant P" ratios for the type of mineralization encountered in the field. The multiband technique also permitted selection of the most significant of another set of windows in the backscattered gammarayspectrum to measure a newly developed "S-factor", a ratio sensitive to borehole diameter. Another window provided information on bulk density. All these measurements were made with a single pass of the same loggingprobe.

Jan 1, 1977

By J. W. Thompson

"The Republic of Colombia on December 30, 1919, enacted a new petroleum law. The Act is expressly limited to mineral oil, natural gas, bitumen, wax and fossilized resin and to asphalt intended for export.The law is not only intended to encourage local investors, but to attract foreign capitalists for oil development. Provision is made for a special edition ion of the law in such languages as the Government may deem necessary to give it extensive circulation within the country and abroad. The published editions must contain the provisions of the law relating to alienship and naturalization.All public lands, or what are termed unclaimed lands, are open to flee prospecting for the purpose of discovering the deposits named in the law, A prospector must obtain from the Government a, license which binds him to deliver to the Government topographic plans of the lands prospected, together with reports of their prospective yielding capacity. This license does not vest the li¬censee with any preferential right for contracting or leasing and may be drawn by the Government at any time.If a discovery is made by a licensee of any of the deposits named and he desires to exploit the same, he must present a memorial or application to the Ministry of Public Works, stating:- (a) the location and municipal district in which deposit beds are found; (b) boundaries of the zone of exploitation, which shall not be more than 5,000 or less than 1,000 hectares; (c) the names and nationality of all persons for whom the lease is sought and the action and time within which,they propose to make the exploitation; (d) the name of the corporation and its legal representatives with their residences; (e) if an alien, he must state his willingness to comply with the law relative to alienship and naturalization; (f) agreement to abide by all of the provieions of the law with regard to Government supervision, payment of taxes, rate of lease and causes of forfeiture; (g) the rate of rent or royalty that the applicant offers to pay, together with any other circumstances that may make the proposed lease advantageous to the Nation."

Apr 1, 1920

By J. R. Thoenen

Occurrences of titanium, zircon, and other heavy minerals are widespread in Florida. Deposits concentrated as "heavy sands" by wave and wind action have been mined an or near Atlantic coastal beaches since 1916. An important inland concentration at Trail Ridge; .believed, to have formed along an ancient share line, was disclosed by preliminary investigations (1947) by the Bureau of Mines. This report describes investigations to determine the extent and grade of "heavy-sand" concentrations in other inland stabilized dune areas in the central and northeastern parts of the peninsular region of the State (fig. 1). Portions of the central highlands south of Trail Ridge and terraces and dunes in the coastal lowlands region, east and northeast of the ridge were investigated. Holes were drilled in 10 areas (see table 1 and fig. 2) along State and County roads and on private property. They were spaced 250 to 2,000 feet. apart to obtain a cross-sectional picture of "heavy-sand" content in the dune areas. These sections were generally placed in east-west directions normal to the general trend Of the peninsula to intercept one or more of the ancient shore lines in the various areas (figs. 3 to 13, incl.). A total of 433 drive piped and 333 jet holes were drilled, and 7,293 bulk and core samples were taken. Intermediate holes were placed at closer intervals when field analysis indicated 1 percent or more of heavy minerals present. All of the holes drilled and the analysis of samples that contain 1 percent or more of heavy minerals are listed in table 2. Profiles (figs. 14 to 20, inclusive) show the more favorable concentrations, which are irregular in outline and erratic in mineral content. The highest concentrations averaged 1.0 to more than 2.0 percent heavy-mineral content, but a few individual hole samples exceeded 3.0 percent in grade.

Jan 1, 1949

By Bruce Geller

The 2004 Prospectors and Developers Association of Canada (PDAC) conference contained an air of optimism and excitement that has not been seen since 1997. Many segments of the mining industry are alive and well. This is largely a reflection of improved metal prices, themselves due to the strong euro and improvements in Asian economies. Those factors offset higher oil prices, a weaker U.S. dollar and concerns about the Middle East. This report is an overview of the conference. It is supplemented by an examination of conference handouts, abstracts and a few complete papers that are on the PDAC’s Web site www.pdac.ca. Sixty PDAC 2004 abstracts are available at the same site, along with 15 complete papers in PDF format. The conference was held March 7-10 in Toronto, Ontario. It was attended by a record 9,200 delegates from 85 countries. About 8,000 people from 74 countries attended the 2003 conference.

Jan 1, 2004