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By R. W. Allgood

"THE world-wide shortage of elemental sulphur, which became sharply apparent in 1950, has focused attention on the commercial exploitation of sulphur-bearing materials such as pyritic ores, sour natural gas, and smelter gases. Although there •are no known commercial deposits of elemental sulphur in Canada, there are vast quantities of these sulphur-bearing materials. The International Nickel Company of Canada and Canadian Industries Limited have for many years collaborated in an effort to develop economic processes for the recovery of sulphur from the smelter gas arising from Inco's metallurgical operation at Copper Cliff, Ontario. While sulphuric acid has been •produced at Copper Cliff for over twenty years, recent developments will result in a 60 per cent increase in acid production early in 1952 and, later in the year, in commencement of the operation of the largest single unit ever erected for the manufacture of liquid sulphur dioxide.The purpose of this paper is to discuss •briefly the general factors associated with the recovery of sulphur from the Copper Cliff smelter gases and to describe the sulphuric acid operations and the liquid sulphur dioxide development.Processes for the manufacture of elemental sulphur, liquid sulphur dioxide, and sulphuric acid from sulphur-dioxide-bearing smelter gases are well known and in some cases •highly developed."

Jan 1, 1952

By L. Lorio, B. Hilscher, P. Nayak, N. Yoon

"Mining has been a staple to technological advancement ever since the dawn of time. By harnessing the different physical and chemical properties that each mining commodity brings to the table, more and more innovation is developed and manufactured. As these non-renewable resources continue to be extracted, the industry as a whole faces a challenge in finding the next economical deposit as well as declining grade at the current operations. By means of pre-concentration, ore sorting aims to separate the barren material from the valuable ore to reduce energy consumption and tailings generation, while increasing the feed grade, concentrate grade, mill recovery, and revenue. In addition, ore sorting allows the modification of deposit geometallurgy in order to allow the creation of an optimal mill feed. This paper evaluates the applicability and challenges of ore sorting by utilizing the results from four different mines, and reviews them in detail. The mines include one underground and three open pit mines that are precious metal operations. In order to understand the applicability of ore sorting in these operations, initial rock-by-rock test results and different types of assays (atomic adsorption [AA], inductively coupled plasma [ICP], and fire assay) are utilized. Using the assay results, the grade recovery curves for ore sorting are generated and they are further improved by using and developing an ore sorting algorithm, which is discussed in this paper. The application and evaluation of ore sorting in greenfield and brownfield properties will also be discussed. The state of the art ore sorting technologies for both rock-by-rock and bulk sorting are also reviewed in this paper. The future technologies on the horizon, including different combinations of sensors, are explained. The sorting technologies include X-ray transmission (XRT), X-ray fluorescence (XRF), colour, infrared, electromagnetic, and laser induced breakdown spectroscopy (LIBS)."

Jan 1, 2017

By M. D. Johnson, R. K. Bezys

"The majority of Ontario's limestone and dolostone production comes from a few Paleozoic carbonate units. In eastern and central Ontario, Ordovician rock units, which are the main sources for production, include the Oxford, Gull River, Bobcaygeon, Verulam, and Lindsay Formations. They are predominantly utilized for aggregate and cement manufacturing, with the Bobcaygeon Formation being used as a source of building stone. Along the Niagara Escarpment, the Silurian Lockport, A mabel, and Guelph Formations are sources for the limestone industry. The largest tonnage of rock extracted by the industry comes f rom these Silurian units, especially the Lockport and Amabel Formations. These units are used primarily for aggregate, although they are also a source for lime. In southwestern Ontario, the Silurian Bertie Formation and Devonian strata, represented by the Bois Blanc Formation, Onondaga Formation, Detroit River Group, and Dundee Formation, contribute to Ontario's production of lime, cement production and crushed stone. The Detroit River Group (Lucas and Amherstburg Formations) is the main source of the lime and cement produced in the province.Northern areas, which may become significant sources for the industry, include Manitoulin Island, the Lake Timiskaming area, and the James Bay Lowland. IntroductionThe Engineering and Terrain Geology Section of the Ontario Geological Survey has undertaken a geological inventory of all active and abandoned limestone and dolostone quarries in Ontario. This geological study, combined with a commercial study of active quarries carried out by the consulting firm of Derry, Michener, Booth and Wahl, will provide an up-to-date report on the industry in the province and will be published by the Aggregate Resources Section of the Ministry of Natural Resources. This report will follow the format and style of D.F. Hewitt's Ontario Department of Mines Industrial Mineral Reports and Circulars (Hewitt, 1960, I964a, 1964b, 1964c; Hewitt and Vos, 1972). Examinations of the quarries were carried out by geologists in the Paleozoic I Mesozoic Geology Subsection of the Engineering and Terrain Geology Section, and include, in addition to the authors, R,R. Wolf, V.A . Mazur, and D.K. Armstrong in the summer of 1986."

Jan 1, 1988

By M. D. Johnson, R. K. Bezys

"The majority of Ontario's limestone and dolostone production comes from a few Paleozoic carbonate units. In eastern and central Ontario, Ordovician rock units, which are the main sources for production, include the Oxford, Gull River, Bobcaygeon, Verulam, and Lindsay Formations. They are predominantly utilized for aggregate and cement manufacturing, with the Bobcaygeon Formation being used as a source of building stone. Along the Niagara Escarpment, the Silurian Lockport, Amabel, and Guelph Formations are sources for the limestone industry. The largest tonnage of rock extracted by the industry comes from these Silurian units, especially the Lockport and Amabel Formations. These units are used primarily for aggregate, although they are also a source for lime. In southwestern Ontario, the Silurian Bertie Formation and Devonian strata, represented by the Bois Blanc Formation, Onondaga Formation, Detroit River Group, and Dundee Formation, contribute to Ontario's production of lime, cement production and crushed stone. The Detroit River Group (Lucas and Amherstburg Formations) is the main source of the lime and cement produced in the province.Northern areas, which may become significant sources for the industry, include Manitoulin Island, the Lake Timiskaming area, and the James Bay Lowland. IntroductionThe Engineering and Terrain Geology Section of the Ontario Geological Survey has undertaken a geological inventory of all active and abandoned limestone and dolostone quarries in Ontario. This geological study, combined with a commercial study of active quarries carried out by the consulting firm of Derry, Michener, Booth and Wahl, will provide an up-to-date report on the industry in the province and will be published by the Aggregate Resources Section of the Ministry of Natural Resources. This report will follow the format and style of D.F. Hewitt's Ontario Department of Mines Industrial Mineral Reports and Circulars (Hewitt, 1960, I964a, 1964b, 1964c; Hewitt and Vos, 1972). Examinations of the quarries were carried out by geologists in the Paleozoic I Mesozoic Geology Subsection of the Engineering and Terrain Geology Section, and include, in addition to the authors, R,R. Wolf, V.A . Mazur, and D.K. Armstrong in the summer of 1986."

Jan 1, 1988

By Dougla McDonald, Richard Poulin

"Most mine managers in Canada today will agree that one of the keys to mining efficiency and productivity is their human resources. A5 a result, many mines develop some sort of incentive designed to tap their employees' capabilities to the fullest extent. Historically, the most common plans used have been ""piece-rate"" plans, where individual or small groups of miners are paid a financial bonus based on some measure of their productivity. Recently, however, incentive plans that take a more team-based approach have been developed in some Canadian mines. One such plan will be defined in this paper, and its popularity in the industry today discussed.Gainsharing PlansThere are two primary components to a gainsharing plan. The first is a cash incentive, which is paid to all employees and based on factors that are highly correlated with employee productivity, and key to the profitability of the mine. For example, the typical gainsharing cash incentive is based on the cost/unit of metal produced. Management (in consultation with employees in some cases) will establish the budgeted cost per tonne, and any savings in this amount is shared between the company and the employees. The second is a management philosophy and associated communication network, which is designed to foster an environment that encourages information exchanges, communication, participation, and trust between employees and management. The typical gainsharing communication network consists of two tiers of committees. The first, operational committees, include all employees working in the same department or departments which frequently interact. The employees meet monthly with management personnel to discuss problems encountered and brainstorm for solutions. In most cases, these committees will nominate a person in the group to structure the meeting to maximize its efficiency. The second, the screening committee, is a single group consisting of representatives from the various operational groups, whose primary job is to ensure that the plan is effective, and the objectives and results generated by the plan remain consistent with the mine objectives. In short, gainsharing plans tell employees that their bonus depends upon performance and then gives them the opportunity and incentive to affect that performance. The opportunity is provided by a communication network and positive management practices, and the incentive comes in the form of ""intrinsic"" rewards of participation and the ""extrinsic"" rewards of the bonus payments. Figure I will clarify the relationship between the intrinsic and extrinsic rewards."

Jan 1, 1995

By A. Y. Senchenko, S. G. Rybkin, A. V. Aksenov

In gravity processing of gold-containing ore the target produced concentrate which is high gold grade primary concentrate contains a significant amount of cassiterite (SnO2). The plant attempts aiming at concentrate processing using a standard pyrometallurgical technology did not provide any positive results. The present paper is dedicated to development and testing of improved technology for pyrometallurgical processing of rich gold primary concentrate with high cassiterite content. According to material composition study primary concentrates produced at the plant contained 1.5–2.0% Au, 0.1–0.3% Ag, 55–65% SnO2, 20–25% Fe2O3, and 10–15% Fe3O4. The developed technology included alkaline nodulizing of primary concentrate mixed with sodium hydroxide and carbonate at 350–650°? with cake production. In blend nodulizing stannum and iron passed into sodium stannate (Na2SnO3) and sodium ferrate (NaFeO2) respectively. The blend of cake and fluxing agents was smelted at 1,150–1,200°? resulting in dore gold and slag production. Sodium stannate with 360°? melting point is well dissolved in slag system Na2OSiO2- B2O3-CaO. During plant tests 18.5 kg of high gold grade primary concentrate were processed, 1350 g of dore gold and 75 kg of slag were produced. Dore gold contained 16.5% Au, 0.95% Ag, 78.0% Sn, 3.1% Fe. Slag contained 12.4 g/t Au, 6.7 g/t Ag, 9.8% Sn, and 5.6% Fe. Gold recovery to target alloy was equal to 99.58 %, 87.8% of Sn passed into slag. This new technology was accepted for application at the plant.

Jan 1, 2016

By J. C. O'Rourke

"Gibraltar Mines Ltd. has been operating its open pit copper mine for fifteen years. In that time over 140 million tons of waste and low grade material has been placed on the mine waste dumps. Laboratory and in-situ testing indicated that enough leachable copper was recoverable from the dumps to justify a leaching operation which would include the construction of a solvent extraction-electrowinning plant. The plant, which was commissioned in October, 1984 was designed to process 3,000 usgpm of dilute copper solution to produce 5,000 tons per year of high quality cathode copper.This paper deals with the start up and initial year of operation of Gibraltar's SX-EW plant. The three areas: leaching solvent extraction and electrowinning are presented with emphasis on the innovations which were made to help overcome the problems unique to die Gibraltar operation.THE LEACHING CIRCUITThe mines waste dumps are leached to produce a pregnant copper solution as feed to the SX-EW plant. To achieve this the dumps are sprinkled with a mildly acidic solution which percolates through the dump. In travelling through the dumps the solution contacts the surfaces of the liberated copper minerals and disolves the soluble copper into the form of copper sulphate. The leaching reaction is achieved by a combination of bacterial action to oxidize the suphides and solublization of the copper into the acid solution.For the bacterial action to occur the dumps must be at or near the ideal pH of 1.9 - 2.1 and the necessary elements of the reaction must be present. Because a bacterial reaction is involved there is a lag time between the time when the conditions for bacterial growth are achieved and when the bacteria are in their active growth phase. Laboratory tests with Gibraltar ore indicated that bacterial action takes two to three months to reach its maximum rate. See figure 1.The expected lag time for the planned rate of bacterial leaching prompted Gibraltar to start irrigating the dumps in late June 1986 for a plant start up in early fall. The lag time proved to be longer than expected and the dumps took until November to start producing copper at the expected rate. See figure 2."

Jan 1, 1988

By Douglas Lay

Attention has been drawn in the publications of the Department of Mines to the view that veins of two different ages occur in the Cariboo district, namely, those of Jura-Cretaceous age and those of pre" Mississippian age. It has been further pointed out that while there is doubtless a wide distribution of veins of pre-Mississippian age in and about the Barkerville and Stanley areas, and in the vicinity of Round Top mountain and Yank's peak, there is no such wide distribution of veins carrying gold values of commercial significance. Veins of the latter type discovered to date occur almost exclusively within one or other of two comparatively narrow zones, both trending northwest and southeast, the one extending from Island mountain co Round Top mountain, and the other from a point somewhat north of Stanley co Yank's peak. In addition, there is some evidence of a third zone trending northwest from Spanish mountain, at or near the contact of the pre-Cambrian and Mesozoic rocks. In short, all the evidence from prospecting and lode-mining operations to date indicates that values are mainly restricted co zones having marked directional distribution. Moreover, it can be demonstrated that the placer deposits resulting from the erosion of the pre-Mississippian veins have a similar directional distribution, allowance being made for modifications due to glaciation. The observations offered in this paper are of the nature of a generalization which seeks to explain certain anomalies both in the vein-mineralization and in the -important auriferous-pyrite replacement deposits in limestone which have recently been discovered. For the sake of brevity, the Island Mountain-Round Top Mountain zone will be referred to as Zone No. 1, and the Stanley-Yank's Peak zone as Zone No. 2.

Jan 1, 1936

By Jing Li, Weiqiang Lai, Joe Zhou, Jiezhen Ma, Shuibo Chen, Ashele Copper Company, Feng Gao, Guofu Feng

"Copper-zinc ores often contain gold and silver, which can be recovered into copper concentrate by flotation as by-product. The challenges for operations that produce copper, zinc, gold and silver are the separation of copper and zinc and the low grade of precious metals. Ashele copper-zinc ore in north China contains 2.38% Cu, 0.69% Zn, 0.21 g/t Au and 18.10 g/t Ag and the plant produces copper and zinc concentrates, with gold and silver being recovered into copper concentrate. Copper occurs mainly as chalcopyrite and Zn occurs as sphalerite. Copper is well recovered with a recovery of over 94%. However, the recovery of Zn is substantially low (around 50%) due to fine grain size of sphalerite. In addition, gold recovery is much lower than expected and only 33% of gold in the flotation feed was recovered. The grade of gold in copper concentrate is also lower than the required payable grade (1.0 g/t). To determine the cause for lower Zn and Au recoveries, a plant survey program was conducted on the operation. The information acquired shows that the loss of Zn was mainly in the copper concentrates (accounting for approximately 38% of the head assay); of which, 24% was liberated, 8.5% was associated with chalcopyrite and 4.6% was associated with pyrite, indicating that the separation of copper and zinc was the main cause for the Zn loss, with liberation being the second cause for Zn loss. Future effort in improving Zn recovery should be focused on the separation of zinc from copper. Gold in the ore occurs as both microscopic gold and submicroscopic gold, accounting for 36% and 64% of the head assay, respectively. Microscopic gold occurs mainly as native gold and electrum; it is relatively coarse with a grain size of 10 to 240 µm and a large portion can be recovered by gravity. Submicroscopic gold was mainly carried by pyrite (accounting for 38%), and to a less extent, by tennantite (15%) and chalcopyrite (10%). Gold in sphalerite is nominal (1%). It is suggested that more coarse gold and tennantite be recovered and a gold recovery increase can then be achieved to obtain a copper concentrate with over 1.0 g/t Au through flowsheet optimization. Gravity concentration should be investigated and may be worth added into the existing flowsheet to maximum the gold recovery and grade.INTRODUCTIONCopper-zinc ores containing gold and silver is a subtype of polymetallic sulphide ores. Unlike porphyry copper sulphide ores and iron-oxide copper-gold ores, this type of ores often contains substantial amounts of zinc and lead. Polymetallic sulphide ores are mainly distributed in Canada, such as at the LaRonde and Horne deposits. Other examples include Mt. Morgan in Australia and Boliden in Sweden. Globally, production and reserves from gold-rich VMS deposits account for 1370 t gold. This is equivalent to 1% of the world production and reserves, whereas the Canadian total for gold-rich VMS deposits is 870 t, representing close to 10 % of Canadian production and reserves (Gosselin & Dube, 2005a, 2005b). Flotation is the principal process for processing the copper-zinc sulphides ores, for subsequent smelting, roasting, or hydrometallurgical treatment. Oxidized copper-zinc ores can also be processed using leaching technology. For example, at LaRonde operation (a Cu-Zn-Pb ore containing 3-4 g/t Au and 60-100 g/t Ag) the flowsheet consists mainly of a copper flotation circuit and a zinc flotation circuit followed by a cyanidation process of flotation tails. The precious metals are recovered with copper concentrate, zinc concentrate and cyanidation of zinc tails via Merrill Crowe precipitation (Zhou et al., 2005)."

Jan 1, 2016

By Richard Lavallée

La Mine Louvicourt est une mine hautement mécanisée exploitant un gisement polymétallique avec des chantiers transversaux minés et remblayés selon une séquence primaire-secondaire. Dans certaines parties du gisement, il n'y avait qu'un accès à la coupe inférieure, car il n'était pas rentable d'avoir aussi un accès par coupe supérieure. Le minerai situé au-dessus des chantiers avec trous ascendants était considéré comme ressource non rentable par minage mécanisé. L'option de miner ces ressources avec des sous-niveaux avec accès par monterie alimak et forage long-trous de petit diamètre fût donc étudiée et démontra une rentabilité intéressante, particulièrement en considérant les tonnes ainsi minées comme tonnage supplémentaire au tonnage planifié. Dans ces chantiers, les détonateurs électroniques ont été très utiles et de plus, les coûts d'explosifs ont étés réduits considérablement par l'utilisation d'émulsion pompée en vrac.

Oct 1, 2004

By W. Andrew Falls

Although we have yet to reach the midway point in the decade, the copper concentrate market has already witnessed some of the most volatile swings in history, moving from record high treatment and refining charges in 1991-92 to historic lows, in real terms, during the past year. What has been the cause for such volatility? By and large the swings can be attributed to factors of supply and demand in the "custom" copper concentrate market. For example, two relatively recent events which had a major impact on the supply-demand balance were the shutdown of the Bougainville copper mine in Papua New Guinea in 1989 due to rebel insurgency and the startup of the La Escondida mine in Chile in 1992. The first event, threw a balanced to slightly surplus concentrate market into a substantial deficit, forcing treatment terms down as smelters, caught short by the loss of concentrate supplies scrambled to cover their positions. The second event, brought over 300,000 mt per year of new copper in concentrate to the market, more than reversing the losses from the Bougainville shutdown. In combination with other additions to mine capacity via new mines or expansions, the custom concentrate market moved into a huge oversupply in 1991-92 and many mines found themselves unable to place uncommitted tonnage. But even this event was quickly overcome by the use of underutilized capacity at non-traditional buyers, such as those in the C.I.S., Zambia, or those which were not traditionally buyers of custom materials. All of this has happened in the space of five short years, a mere snapshot in the history of the market. I'll return to these points a little further on, but first I would like to review the fundamentals which govern the copper concentrate market.

Jan 1, 1995

By J. S. Stewart

THIS paper was prompted by a persistent demand for what information we have that will throw light on the oil and gas possibilities of the Maritime Provinces. The problems involved were made familiar to the writer during three seasons of field work in New Brunswick and Nova Scotia. The reasons for renewed interest are: (1) In many parts of that region, the surface is underlain by a thick series of unaltered sedimentary rocks. (2) Oil seepages occur, and oil in commercial quantity has been exploited' near Moncton, New Brunswick, for many years. (3) In recent years, a new method of attack has been developed toward the finding of stratigraphic traps. This method is based on a detailed study of the geological history of the region, as revealed in surface outcrops and samples from deep wells. The well samples show the lateral variation of strata, far from any possible surface outcrop of the same beds. Sufficient work has now been done in the Maritime Provinces to reveal the broad features of the geological history and the character and distribution of the various rock formations. Comparatively little deep drilling has been done in this region, but the holes are widely scattered and the samples from them have added much to the information obtained from the numerous outcrops of bed-rock. The following discussion gives a summary of available information that has a bearing on the subject.

Jan 1, 1943

By C. H. Lee, T. T. Wang

"Exampling of the tunneling task in the Tsengwen Reservoir Transbasin Diversion (TRTD) in southern Taiwan, this study investigates the application of the Drilling Survey System (DRISS) in both Drilling and Blasting (D&B)- and Tunnel Boring Machine (TBM)-excavated sections. In the D&B section, a nonlinear relationship exists between drilling energy and uniaxial compressive strength of rock mass, in which a reasonable coefficient of determination can be analyzed statistically. Additionally, the DRISS accurately predicted an unfavorable section with a valuable position. The magnitude of uniaxial compressive strength back calculated using DRISS data also matches those acquired from geological investigations with different approaches. Study results indicate that the DRISS is an effective tool for fore-probing of both D&B- and TBM-excavated tunnels. INTRODUCTIONModern advancements in geological and geophysical investigations, and drilling techniques, have provided valuable information for detecting and interpreting geological conditions of rock tunnels with a resolution of several to ten of meters (Brückl et al., 2001, 2008, Lorang et al., 2005). Nevertheless, construction risks remain considerable during tunnel excavation, especially when a tunnel was excavated by a Tunnel Boring Machine (TBM). Predictions of the local fault, shear zone, and other minor geological features, which may cause moderate collapse or excessive deformation of rocks surrounding the tunnel, before tunnel excavation is highly desirable for high-quality tunnel construction and economically efficient project management.Rather than conventional geophysical prospection methodologies, which always favor large-scale investigation with moderate precision, this study focuses on the drilling method probing ahead of a tunnel. The goal of such an investigation is not only to prevent catastrophic collapse, but also to provide quantitative or semi-quantitative information for estimation of the mechanical parameters of rock mass.For the tunneling task in the Tsengwen Reservoir Transbasin Diversion (TRTD) in southern Taiwan, a drilling survey system is adopted for fore probing. Data collected from both drilling and blasting (D&B) and TBM-excavated sections are analyzed statistically and discussed. The applications of the Drilling Survey System (DRISS) are addressed accordingly."

Jan 1, 2015

By Beatrice Pierre, Juan Carrasco

Altonorte began as a concentrate roasting operation in 1988 under the name of Refimet. In 1993, a copper smelter was built with a design capacity of 203,000 tonnes per annum of concentrate. Since 2001, many technological advances have been made in Altonorte, where the biggest Noranda Reactor in the world is installed being the first Noranda Reactor reaching above one million tonnes of copper concentrates processed per annum. In 2013, Altonorte was acquired by Glencore. Recently due to various new environmental regulations in Chile, Altonorte has evolved to new standards of operation in order to reach the vision of becoming a World Class Smelter. This paper describes the path followed to improve safety, environmental performance, process capacity, reliability, and productivity. The foundation for the growth and success in Altonorte is our People. Employee engagement and branding of our cultural journey is what allows Altonorte to face the future with the certainty of becoming a World Class Smelter. INTRODUCTION Altonorte is located in Antofagasta, the mining capital in the north of Chile and is the last smelter built in Chile practically completed with second hand equipment. The biggest technological change in Altonorte occurred during the phase 3 expansion in 2003, where the old Reverberatory furnace was shut down and replaced by the biggest Noranda Reactor installed in the world. The vessel measures 5.3 m × 26m. ºAdditionally, this project contemplated a new rotary dryer, three (3) new Peirce Smith converters, new anode furnaces and a new Acid plant. The nominal capacity was to treat 816.000 tons of new concentrate per year. In 2008, a new expansion phase was implemented where a new double absorption acid plant replaced the oldest acid plant. Bottlenecks such as blowing capacity and oxygen availability were solved installing a new air blower and a new contract was negotiated with our oxygen supplier to increase oxygen availability up to 683 tpd. This improvement defined the current nominal capacity of 1.100.000 ton of new concentrate per year. Current process description All concentrates are received by trucks directly from domestic mines or from the Antofagasta international port in cases of imported concentrates; the concentrate warehouse has a capacity of 25 kt where the blend is prepared to feed the smelter.

Jan 1, 2019

By F. Charette

Instrumentation has been developed that can monitor the strain applied to a D-Bolt up to 7.5% elongation. The technology far exceeds the limit for foil resistance strain gauges. In the laboratory the instrumentation has provided insight into the fundamental behaviour of the D-Bolt following yield. Currently the instrumentation is undergoing field trials at a number of Canadian Mines. Discussion on field results is provided with regards to significance, reliability and temperature effects.

Aug 1, 2013

By Baisheng Nie, Longlong Yang, Tao Yang, Wenjie Jia

"Gas adsorption in coal is an exothermic and physical process. Temperature might change during the dynamical process. In order to get the temperature variation of gas adsorption process, the experiment system which can test the temperature variation and analyze the thermal effect was established. Gas adsorption experiments under different conditions were done by using the test system. The results show that temperature increases during the adsorption process. It is an exothermic reaction process. Also, the temperature variation and the variation gradient increase with the increasing of equilibrium pressure. The temperature variation value is smaller if the experiment temperature is higher. The paper will provide basic experimental data for explaining gas adsorption mechanism better.INTRODUCTIONChina is the largest coal producer in the world while it also has the most serious coal mine disasters. According to the statistics, there are nearly a thousand coal mines in China including more than 110 the key state-owned mines risking to happen coal and gas outburst. Hundreds of coal and gas outburst occur each year which often causes serious casualties and economic losses (State Administration of Work Safety, 2007). With the continuing exploitation of the coal resources, the depth of the Chinese coal mines increases about 100 meters every year which causes the situation of gas accident becoming more and more serious (Xie et al., 2006).At present, the real mechanism of gas adsorption, desorption and the diffusion process in coal and the influence factor of it are not so clear. And because of the limit of prediction method and the technological level caused gas accident prevention theory and technology not so valid."

Jan 1, 2015

Situation Brands & Employment Value Propositions of mining sector firms are perceived negatively Competitive labour market is generally not aware of the diversity of mining careers Jobs requiring unique skills & experiences are no filled Traditional means of generating awareness to attract candidates is not aligned with how youth (for example) uses technology throughout the recruitment process Gobal economic downturn

May 1, 2009

By A. Vervoort

The concepts of geostatistics are commonly difficult to understand for students, even for those with a strong mathematical background. A main problem is certainly the link between the variation of the parameter value in space or time, and the calculated experimental semivariogram as a function of the interdistance, but over the entire area. Another problem is to differentiate between directional and omnidirectional semivariograms and the way they have to be interpreted. Furthermore first time users of geostatistics often do not want to struggle through different books with the whole geostatistical background before using it. Too often this leads to using geostatistics as a black box with all the risks linked to it. That is the main reason that we developed some interactive tools based on the free public domain software R. We aim by developing three different modules to assist individual first time users, but also regular students and teachers to get a feeling of the importance of the various aspects in conducting a good geostatistical study. The modules show directly e.g. the impact of deleting, moving or adding data points, of changing parameters of the semivariogram model and of the geometrical parameters during kriging. The first module allows making the link between the variation of the parameter values in one direction and the calculated experimental semivariogram, and this for different given datasets. The second module covers two dimensional datasets and apart from calculating the semivariogram values, models can be fitted to the calculated data. A distinction can be made between omni-directional and directional semivariograms, including the effect of the tolerance on the angle and lag-distance. The third module focuses on ordinary kriging of point values in two dimensions. The aim of the interactive tools developed is limited to educational purposes only, i.e. to visualize some basic concepts for different pre-selected types of spatial variation. They do not intend to do a geostatistical study on a certain dataset (for this purpose there exists already a broad spectrum of good software packages). The original intention of developing the three modules was aimed at users with no or a limited amount of geostatistical experience. However, these modules seem also very useful to remain critical for experienced users. One should never forget that in a real application one does not have a complete view of the phenomenon studied. The geostatistical interactive modules can be accessed through: www.bwk.kuleuven.be/geostatistics . We compiled a manual to facilitate the use of the modules and to guide the user we formulated several questions to be solved for each module.

Aug 1, 2013

By J. Ipinza, J. P. Ibáñez, Casas J., S. Cortés

Copper powder generated during the treatment of electro-metallurgical bleeds by reactive electro- dialysis (RED) had totally reduced the content of ferric ions in acidic synthetic electrolytes (Cu (II)- Fe (III) – H2SO4). In batch and columnar experiments 100% of the ferric ions were reduced to ferrous ions with an extremely high kinetics. A preliminary conceptual design for reducing ferric ions based on an integrate RED- Column for treatment of electro-winning bleed system is discussed. This system is able to recover simultaneously sulfuric acid and copper powder, which will reduce ferric ions. INTRODUCTION It is well known the negative effect of ferric ions in the copper electro-winning process. The increase of ferric content in the electrolyte reduces the current efficiency, i.e., there is an increase in the energy consumption, and changes the surface morphology of the copper deposit (Das, Gopala & Krishna, 1996; Vargas & Parra, 2013). The increase of the specific energy consumption due to the loss of current efficiency occurs by the reduction reaction of ferric to ferrous ions in the cathode, at the anode the ferrous ions are slowly oxidized to ferric ions (Shaw, Dreisinger, Lancaster, Richmond & Tomlinson, 2004). To control the level of iron in the electrolyte, bleeds are needed; this bleed electrolyte containing copper, sulfuric acid, cobalt, iron and other impurities normally is waster, which increased the production cost of the plant (Milbourne, 2002; Mckevitt & Dreisinger, 2009). Then, permanent efforts oriented to treat those bleeds to avoid losses of valuables components are made; among them are use ion exchange resins (Shaw et al., 2004; Mackevitt et al., 2009), chemical precipitation (Izadi, Mohebbi, Amiri & Izadi, 2017) and electrodialysis (Cortés, Ipinza & Ibáñez, 2013). The last one allows to the simultaneous recovery of sulfuric acid and copper powder. If one of the valuables obtained by treating the bleed can be used to reduce ferric ion concentration in the electrolyte could be an important asset. This issue at laboratory scale is reported in this work, the use of copper powder, generated by reactive electro-dialysis when treating synthetic acidic electro-metallurgical bleeds, for reducing ferric ions in acidic electrolytes.

Jan 1, 2019

By L. Li

Backfill is increasingly used in underground mines, as it can help reduce the environmental impact from mining operations. However, the primary objective of backfilling is to provide safe working space for miners, by improving ground stability conditions. As cement is often added to the backfill, a critical issue is the determination of the required backfill strength (cohesion) due to the binder. This value is usually obtained from a solution proposed by Mitchell and co-workers, in the early 1980?s, for stopes with an exposed backfill face. This paper presents a brief review of the Mitchell et al. solution, with some of its main limitations. Some of the recently developed solutions for backfill design are then summarized and discussed.

Aug 1, 2013