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By C A. Fleming

Gold extraction is largely driven by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery include grain size and shape, surface coating or rimming on gold particles, the presence of cyanide or oxygen-consuming minerals or preg-robbers, the presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking of fine gold particles in sulfide, silicate and other minerals, either as visible, fine-grained gold inclusions and/or as invisible submicroscopic gold, is by far the most common factor leading to poor gold recovery in gold ore processing. This paper discusses the mineralogical characterisation of gold lost in tailings and its metallurgical implications. The techniques used in characterising the un-recovered gold are also briefly introduced.

Jan 1, 2007

By Y. Nakata, K. Nagata

Plasma is partially ionized gas composed of ions, electrons and activated elements at high temperature. Some flying ash from incinerated municipal waste is melted to become glass by a transfer-type arc plasma furnace. As the glass is ionic silicate, when an electric current passes through anode to cathode, ions in molten slag electrochemically react with electron in plasma at the surface of molten slag. In case of molten Na2O-SiO2, sodium ions in the molten slag carry electric current and SiO2are reduced to evaporate as SiO gas by electron in plasma. The cases of Ag+in NaNO3-KNO3molten salt and Fe2+in FeO-SiO2slag were examined. The amount of cathodic reaction is larger than that of anodic reaction and not apparently according to the Faraday?s law on the electrochemical reactions.

Jan 1, 2004

By R A. Lynch, D A. Malovichko

The implementation of routine real-time micro-seismic monitoring of open pit mine slopes has been discussed. Some examples of seismic arrays have been given, and a recommendation of suitable seismic sensors made. Unfortunately near-surface sensors are required for good location accuracy, and the effects of reflection, mode conversion and surface waves must be accepted and compensated for during processing of the seismograms. It makes sense that mining at the base of a slope and levels of seismic activity within the slope should be related, and this is confirmed using both 2002-2003 and 2005 seismic data recorded at Navachab mine. An example of how seismic data can be used to gain information about seismically active geological structures has been described. The removal of broken rock, and not blasting nor the breaking of supporting rock, has been found to cause slope micro-seismicity. While the standard Brune source model is suitable for some 20% of the seismic events, unreasonable results are obtained for the rest. A moment tensor inversion has been performed after S-wave splitting and surface effects have been filtered out. This approach confirms a predominantly shear mechanism for a typical high frequency source.

Jan 1, 2006

Recent and on-going studies on the leaching of gold, the properties and activity of carbon, developments in the elution of gold from carbon, and methods of recovering gold from solution are reviewed. Emphasis is placed on Australian contributions, and their impact on gold metallurgy. Consideration is given to the future development of selective solvent extractants, ion exchange resins or alternative reagents for cyanide.

Jan 1, 1987

By J. Goyman, K. R. Rawling

"1.1 Location and Transportation ServicesNanisivik Mines Ltd. is located at latitude 73°, 3,200 km north of Montreal and 700 km north of the Arctic circle, on the south side of Strathcona Sound, which is an arm of Admiralty Inlet, in Northern Baffin Island. The orebody and mill site are 4 km distant from Strathcona Sound which provides deep water anchorage for ocean transportation of concentrate to Europe during the short northern shipping season from mid-July to mid-October.The operations and the resident community have direct jet aircraft service from Montreal two days per week, and local nights connect with other Arctic communities in the northern Baffin region. Bulk supplies and general cargo are delivered in the summer shipping season.1.2 HistoryThe Texas Gulf Sulphur Company, now Kidd Creek Mines Limited, staked claims in the Nanisivik area in 1957 and carried out exploration through to 1968. After the Kidd Creek orebody was found, Texas Gulf optioned the property in 1972 to Mineral Resources International Inc. (MRI), which undertook further exploration and completed a feasibility study.Nanisivik Mines Ltd. was formed in 1975, with MRI as the majority shareholder and minority shareholdings held by Metallgesellschaft, Billiton and Texas Gulf. Strathcona Mineral Services Limited was retained to manage the project during both the construction and operational phases."

Jan 1, 1984

By Anil K. Beersing

Effective drainage systems are required for reclamation of mine-disturbed areas to control surface water runoff and avoid excessive erosion. For the conventional structural design approach, armouring material necessary to satisfy the design criteria should not move during the design flood event since displacement would uncover the erodible underlying materials. This paper discusses an alternative geomorphic approach for designing drainage channels and watershed landscape. The approach is based on quantitative studies of geomorphic processes operating in a watershed. A design based on the geomorphic approach replicates the configuration, channel regime, sediment volume and hydrology of natural and mature drainage systems. Movement of some armouring material is acceptable in such an approach because the channels are allowed to mature by natural degradation and aggradation, with erosion rates comparable to the natural environment. The key advantages of a geomorphic approach over a purely structural approach include reduced sizes of armouring material, geomorphologically sustainable landscapes, ?walk-away? or maintenance-free design and reduced liability in the future. The geomorphic approach is illustrated using the example of a coal mining operation in northwest U.S.A. The paper discusses field data collection, design criteria, typical design details, and construction methods.

Apr 1, 2005

By Dave Rose, David G. Meadows, Mike Westendorf

"Copper Mountain’s concentrator was commissioned in May 2011. The circuit consists of a 34’ x 20’ EGL SAG mill, a Raptor 900 pebble crusher and two 24’ x 39’6” ball mills. Each mill is equipped with a 2 x 8500 HP dual pinion drive system. The plant was designed to process 1585 mtph of SAG feed. From startup, the mill struggled to meet the required production rates. Over time, a major initiative that involved blasting and fragmentation, optimization of the SAG mill in terms of discharge grates, ball size and slurry density, and operation of up to three mobile pre-crushing plants resulted in significant increases in throughput. In parallel, a number of modeling tools, including JK SimMet, were run based on plant benchmarking exercises. Samples collected at the mine site during ramp up confirmed the very competent nature of the ore with drop weight - A*b values of less than 24 being recorded on a variety of plant feeds and lithologies. After due consideration including demonstration of proof of concept, a new pre-crushing circuit incorporating an XL2000 cone crusher and associated screening equipment was designed, constructed and commissioned at the site in August 2014. This paper reviews the history of the original circuit design, the various optimization steps taken and impacts, together with the final pre-crushing circuit and net results.IntroductionThe Copper Mountain Mine is located approximately 20 km south of Princeton, British Columbia, Canada (refer to Figure 1). The region has a long history of copper mining dating back to 1923. The Copper Mountain camp occurs in the 'eastern volcanic belt' of the Nicola Group (Monger, 1989). It is an alkali copper-gold deposit in which the volcanic strata are intruded by early Jurassic dykes, sills, irregular plugs and zoned plutons (Woodsworth et al., 1992). The stratified rocks are relatively fresh with slight metamorphism in the local contact regions."

Jan 1, 2016

By Gregory Poole

With access to the World Wide Web, many resources are readily available for improving claim reports. With a little time spent on line, a more thorough report can be created. Claimants will accept the conclusions of a report more readily when they can view support information on their own computer, particularly when the support information is not just from blasting related web sites. Some suggested resources are discussed including aerial pictures, local tax maps, topographical maps and home repair web sites. This paper provides suggestions for tracking down support information on the web and information on how to properly reference this information. Case studies of several claim investigations are presented. These are some examples of how a little time spent online provided clear and convincing evidence to support the conclusions of the investigation.

Jan 1, 2006

By Liane J. Terrill

Rockbolt failures at the Waste Isolation Pilot Plant have been recorded since 1990 and are categorized in terms of mode of failure. The failures are evaluated in terms of physical location of installation within the mine, local excavation geometry and stratigraphy, proximity to other excavations or shafts, and excavation age. The database of failures has revealed discrete areas of the mine containing relatively large numbers of failures. The results of metallurgical analyses and standard rockbolt load testing have generally been in agreement with the in situ evaluations.

Jan 1, 1995

By Jean Cayouette

"In 1995, Louvicourt Mine started one of the first paste backfill operations in Canada. From 500,000 tonnes in 1995, the annual paste backfill tonnage produced reached 800,000 tonnes in 1999. The maximum throughput of the surface plant (including binders) is 3,50Ot/d with a final density of 75 to 76% solids which gives a slump of 15 to 17cm. Following the start-up of the paste backfill plant, the backfill strength performance levels were well below the pilot plant’s predictions. The introduction of ferrous slag, laboratory tests on various binder ratios with or without additives, and the desliming of the tailings enabled us to optimize the mix and operation costs. Primary and secondary stopes are filled respectively with a paste containing 4.5% and 2% binders consisting of a mixture of 20% cement and 80% ferrous slag. In certain stopes, the binder ratio may vary from 2 to 7%, but always in a ratio of 80/20. Six years after start-up, or 4.5mt of paste backfill later, this paper discusses the present operation and the major changes that have occurred over the years to optimize both the operation and the paste fill quality.INTRODUCTIONLouvicourt Mine is operated by Aur Resources Inc. which owns 30% of the shares. Its partners are Novicourt Inc. (45%, subsidiary of Noranda Inc.) and Teck Corporation (25%). The mine is located in the north-west part of Quebec, about 600 km north of Montreal and about 25 km east of Val d’Or. The mine commenced commercial production in July 1994."

Jan 1, 2002

The zinc-lead lode at Rosebery, on the West coast of Tasmania, has a total length of over 4000 ft. It consists of five elongated lenses parallel to the foliation planes of the quartz sericite schist, and is situated at the junction of the quartz sericite schist and a thin belt of slate. The lenses consist of massive, fine grained sulphide ore, with small amounts of quartz, barite, sericite and chlorite, and they terminate in masses of low grade ore. The gangue minerals increase in quantity in the low grade ore which includes small quantities of the manganese garnet, spessartite. The schist walls of the lenses are in places impregnated with lode minerals to a degree sufficient to permit them to be regarded as economic ore.The ore-bodies have developed from incoming mineral solutions by the replacement of the quartz sericite schist and are localised where the ore solutions have been confined by a relatively impervious slate band. The early stages of replacement of the schists are signified by the development of pyritic bands which are succeeded by a strong development of zinc blende. With ptogressive crystallisation, the character of the mineral solutions gradually changed and the development of galena, and its associated bournonite, became more important in the later stages.Remnants of the replaced schist, in the form of isolated wisps and schlieren of sericite and chlorite, are present in the ore body, more noticeably in the pyritic specimens. An important feature of the ore is the association of small ogllantities of gold with trahedrite.

Jan 1, 1934

By Forrest T. Moyer

INJURY experience and employment data are presented in this (chapter for metal and nonmetal mines, stone quarries, sand and gravel pits, iron-blast-furnace slag plants, and metallurgical plants (including ore-dressing and nonferrous reduction plants and refineries) in the United States. Employment and injury experience data for all mineral industries are given in volume III. The 1963 figures are preliminary and are subject to revision. METAL MINES Preliminary estimates for the metal-mining industry of a combined fatal and nonfatal injury-frequency rate of 32.34 per million man-hours in 1963 indicate only a slight change from the rate of 32.00 in 1962. Metal operations had 41 fatal and 3,110 nonfatal injuries during 1963.

Jan 1, 1964

By L. Chen, G. A. Brooks, S. A. Nightingale

The dissolution of alumina and magnesia has been investigated using laser scanning confocal microscopy (alumina) and a rotating finger apparatus (magnesia) to assess the effects of temperature, composition and forced convection on the rate of dissolution in CaO-SiO2-Al2O3based slags. The two techniques have differing strengths and limitations, and provide complementary methods for studying dissolution. Alumina dissolution was studied for temperatures from 1477 to 1577°C. Based upon the data, the rate controlling mechanism was thought to be mass transfer control in the slag. The diffusion coefficients for the alumina particles are estimated to be in the range 10-11to 10-10m2.s. MgO degradation for sample rotation speeds of 50 to 800 rpm at 1500 and 1530°C was studied for both congruent and incongruent dissolution. The results show that the rate of dissolution for this is primarily controlled by a diffusion mass transfer mechanism for congruent dissolution except at the highest rotation speed. For incongruent dissolution, the mechanism is much more complex, with the morphology and distribution of the spinel reaction product having a significant effect. At high speeds and prolonged times, mechanical forces played a major role in the degradation process. Keywords; kinetics, corrosion, refractories, dissolution rate, inclusions, mass transfer, slags, steelmaking

Jan 1, 2004

A practical core-based method for estimating in situ stress was tested using 360° measurements of rock core diameter in a laboratory setting. In several mining districts across West Virginia, rock cores were recovered from exploration core holes and oriented using an acoustic televiewer (ATV) summary log. Measurements of diametral variation were performed at 0.1-foot depth intervals using a benchtop device comprised of a pair of diametrically opposed contact digital indicator gauges working in tandem. The diametral profiles were evaluated to determine strain direction and strain magnitude. Stress magnitudes were calculated when values for Young’s modulus, and Poisson’s ratio were available. Stress direction results are compared to other stress determination methods, including downhole overcores, drilling-induced fractures, and borehole breakouts. The testing and analytical methods used are similar to the diametrical core deformation analysis (DCDA) method (Ito, Funato, and Shono, 2012), but with a number of important improvements.

Jan 7, 2020

Comparative Studies on Balls Versus Spheroidal Tetrahedrons Working Media to Ore Grinding in an Industrial Drum Mill

Sep 13, 2010

By Dave Bulled, Khiratt Husain

"The use of High Pressure Grinding Rolls is gaining significant interest as a replacement for SAG milling in the comminution of hard rock ores because of the potential for reduced costs in terms of energy and grinding ball consumption. Estimation of expected energy consumption for fullscale operations has conventionally involved the testing of a few fairly large samples in pilot scale HPGRs. This paper describes the development of a small-scale batch test method for determining a work index for HPGR of a large number of samples that can be used to show the variability of the ore as an integral part of a geometallurgical approach to circuit design and production forecasting.The test equipment that was developed comprises a hydraulic press with adjustable pressure operating on small batches of ore in a locked cycle test procedure. A work index measurement was determined that links the specific energy consumed in the test to the breakage achieved such that the index can be used to predict comminution energy requirements.The measurements were calibrated against laboratory scale HPGR equipment to develop a model for design and forecasting that includes crushers, HPGRs and ball mills in a complete comminution circuit.INTRODUCTIONEstimation of the expected energy consumption for full-scale HPGR operations has conventionally involved the testing of a few fairly large samples in laboratory and pilot scale machines (Danilkewich, 2006). With the financial input of five mining corporations, SGS Lakefield Research has developed a small scale test capable of providing relevant information on the variability of energy consumption and size reduction from drill core samples. It is our intention that the values measured in the test will be scaled up, through benchmark comparison with pilot sized and full sized HPGR units, to allow plant design and throughput forecast on a block by block basis of the mine plan using a new CEET program. CEET® (an acronym for Comminution Economic Evaluation Tool) is an advanced grinding design and performance predicting tool that uses energy relationships to model the performance of SAG / Ball mill circuits."

Jan 1, 2008

By M. England

Keywords: Bi-directional tests, Osterberg cell, O-cell®, static load tests, Timeset® Static load testing, where loads are applied vertically to the top of the pile and often referred to as 'top down testing', has been used for many years and has become a 'standard' test for the world of foundation engineering. The method, although well developed, cannot be used under certain circumstances, magnitude of load being a particular issue. There is a finite limit to the load capacity that can be applied with either kentledge, the use of reaction piles or anchors, and as the loads increase, the costs escalate dramatically. A novel test method seeks to overcome all the associated problems of large scale and restrictive area "top down testing", utilising static load testing techniques. The method requires the foundation element to be divided into two or more sections and these can be loaded axially as required using a portion of the foundation element as a reaction. This paper presents some recent applications and developments in the use and application of the bi-directional testing technique using the Osterberg Cell or O-cell® and outlines some of the many advantages of the system. Recent bi-directional test loads applied to bored piles have mobilised capacities of 279 MN and with flight auger piles up to 25 MN.

Jan 1, 2006

By J. Duncan Crone

"A test surface Pulse EM(PEM) survey over a plunging massive sulphide lens, located in the Snow Lake area of Manitoba, has shown that it is possible to detect the body to a depth of 300 metres. Another surface survey in the Athabasca basin of Saskatchewan, clearly outlined a large, basement graphitic zone below 450 metres of sandstone cover. Deep detection of these conductive bodies was achieved by energizing large volumes of ground with a strong transmitted EM field. Such large fields also energize all other conductors present in the exploration area. Both of the above survey results indicate that more than one conductor is present. In such cases, detailed field coverage is required for accurate interpretation, and interpretational procedures that assume simple geometrical shapes should be applied with caution. In all cases geological and geophysical information should be coordinated in detail. The first test drill hole still has a high risk of missing the deep conductive body and two or three holes should be budgeted per target.Borehole Pulse EM surveys are now routinely used to help zero in on deep conductive targets. They are also proving effective in development drilling programs by outlining the edges of conductive bodies. The results of surveys from northern Quebec illustrate how they may provide more accurate shape and tonnage estimates."

Jan 1, 1985

By D. M. Davidson, P. F. Kerr

The Permian Cutler Formation in Kane Creek, Utah bears uranium ore in fissure-type vertical veins. This fissure vein formation and its associated host rock bleaching, weak argillic alteration, and base-metal sulfide mineralization along with the development of hydrothermal minerals, a 60 m.y. isotopic Pb/U age, and well-crystallized uraninite's structural control, give evidence of ore deposition in a hydrothermal environment consistent with Laramide mineralization. Mica polymorph studies indicate first, that temperature during the hydrothermal alteration or subsequent ore deposition did not exceed 200°; hence Cutler deposits are classified telethermal; and secondly, that rock alteration and ore deposition are closely related both in time and space, as is seen in argillic alteration sequence. Ore deposition in an alkaline to slightly acid reducing environment is postulated. Ore textures and mineral associations and distributions also indicate that carbonate complexes may have been transported with the deposing ores. Bleached rock formations are not primary strati-graphic phenomena. Bleaching, or changes in ferric iron content, results from a chemical process involving reduction and conversion of hematite to a soluble aqueous ion. Nearby Chinle bedded deposits (Moss Rack sandstone), containing shale lenses, fossil wood, organic debris and minor fractures, overly the Cutler formation. Chinle ores have a single reported isotopic age of approximately 200 m.y. Their chemical environment is assumed similar to that of the Cutler ores, though slightly more acidic. Two genetic, paradoxically divergent interpretations of the bedded deposits are derived from available spectrographic, petrographic, X-ray and chemical analyses. Kane Springs canyon is located southwest of Moab, Utah, south of the Colorado River and northwest of the Lisbon Valley mining district (Fig. 1). Uranium deposits occur along the northeast flank of a Kane Creek salt anticline where two geologic formations bear ore, the Permian Cutler and the Triassic Chinle. The Cutler deposits' fissure vein formation is an unusual occurrence in the Colorado Plateau. The Chinle deposits appear to be of the normal sedimentary type. Associated with the vein deposits are a number of features, including argillic alteration of sedimentary strata. The minerals of these deposits and their associated features have been studied in detail in a two year program entailing both field and laboratory techniques. STRATIGRAPHY A stratigraphic section of the lithologic units in the Kane Creek area is given in Table I.

Jan 1, 1967

By Robert W. Bruhn

An investigation was male of ground response to pillar retreat mining in a 1.7 meter thick seam at 108 meter depth at a site in northern West Virginia. This paper describes mining-related stress changes and movements at nine level, displacements within the overburden, ground surface subsidence and groundwater level variations. Subsidence approached 40 per cent of the nine height ad continued more than a year after mining. Water levels declined la certain deep-lying strata.

Jan 1, 1984