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By Jorge Blanco, Joaquin Gotor, Enrique Delgado, Carlos Frias

Since 2009 Cobre las Cruces (CLC) has successfully operated a sustainable mining business near Seville, Spain, applying the most advanced hydrometallurgical technologies to process secondary copper sulphide ores through atmospheric leaching in ferric sulphate media and using oxygen sparging in a cascade of ten reactors. In comparison to conventional copper smelters, the CLC hydrometallurgical process does not generate SO2 gas, airborne emissions or slags. The copper ore is ground and sent directly to atmospheric leaching reactors; flotation is not required, and consequently, copper extraction is maximized at 93-95%, while producing 72,000 t/y copper cathodes of the highest purity (99.999 wt.% Cu, Grade A). Reserves for the CLC deposit were estimated at 16 million tonnes of ore averaging over 6 wt.% Cu and containing principally a chalcocite mineralization. Other copper bearing species include digenite, covellite, chalcopyrite, bornite and enargite. Pyrite represents over 70 wt.% of the ore. In the CLC leaching process, chalcocite reacts with ferric sulphate at approximately 90 ºC and copper is released into solution while ferric ions are reduced to ferrous ions. The ferric sulphate leachant is regenerated continuously by oxygen injection and consumes sulphuric acid. It is remarked that pyrite plays a crucial role to yield high copper leaching rates. When pyrite is oxidized, a small proportion of iron is co-leached and some sulphuric acid is generated. The CLC leaching technology has been designed to allow a certain level of pyrite oxidation, which is positive in many ways: (i) to maintain a Fe/Cu ratio in solution; (ii) to facilitate Fe(II) oxidation; (iii) to produce a high redox potential; and (iv) to counterbalance a bleed solution that removes some iron. Moreover, galvanic interaction between pyrite (cathode) and chalcocite (anode) can substantially increase atmospheric leaching kinetics and efficiency (copper recovery).

Jan 1, 2016

By I. J. Burgess, B. C. Barlow

"The electrodissolution of nickel pellets with different controlled electrical variables was investigated in an effort to mitigate plating residue in Watts bath based electroplating cells. During galvanostatic dissolution at 0.4 A dm-2, the anode potential was seen to oscillate between passive and pitting potentials. In-situ microscopy and ex-situ characterization has shown that lacy-pit formation and large, partially perforated, pit covers form during the potential decay from pitting potentials. In general, covered pitting at low current density shows increased plating residue. Using potential pulses is one way to maintain greater control over surface pitting by creating a higher density of pit nuclei while at the same time controlling their growth. Pits generated from a series potential pulses were examined ex situ for a range of pulse times and stages of pit growth were identified. An alternative method of anode dissolution was devised using potential pulses and duty cycles that allowed average current densities comparable to industrial plating conditions to be achieved. By restricting the time at pitting potentials to 0.05 s, plating residue was reduced more than six-fold in comparison to an equivalent galvanostatic experiment run at a comparable current density.INTRODUCTIONIn typical galvanostatic (direct current) nickel electroplating cells employing soluble anodes, some amount of plating residue is produced which consists of metallic nickel and impurities that detach from the bulk in the form of small fines. Significant buildup of residue requires plating operations be halted and the anode assembly cleaned of residue before operation can resume. While variables in the refining process have been shown to affect plating residue, more precise control of electrochemical variables may provide an attractive route to mitigation of residue."

Jan 1, 2016

By S. Malkin, Z. Shi, H. Attia, D. Chellan

An experimental investigation is reported on creep-feed grinding of a nickelbased alloy (IN718) using conventional aluminum oxide grinding wheels. Straight surface grinding expe.riments were conducted on nickel-based alloy blocks over a wide range of grinding conditions with straight oil as- grinding fluid applied at high pressure. Grinding power, forces, workpiece surface roughness, and radial wheel wear were measured. Specific material removal rate as high as 64 mm2/s was Used without burning the workpiece, which can be attributed to the extremely low specific energy of 12.6 J/mm3. It was found that the grinding wheel under the present test conditions had a strong capability of self-sharpening as indicated by the stabilized power, forces, and surface roughness after an initial short transient.

Jan 1, 2006

By Victor Dolmage

"The localization of orebodies by geological structures is well demonstrated at the Copper Mountain mine of southwestern British Columbia. These extensive deposits; owned and workd by the Granby Consolidated Mining; Smelting and Power Company; are at Princeton; abo!lt 150 miles east of Vancouver and 40 miles north of the International boundary. The geology of the deposits and the surrounding district is described by the present writer in Memoir 171 of the Geological Survey of Canada; pub1ished in 1934.The main geological feature is a gabbro stock, elliptical in plan, with a major axis about 5 miles in length extending in a northwest-southeast direction. The stock varies in composition from syeno-gabbro (gabbro plus orthoclase) through diorite and syenite to a core of syenite pegmatite. All the members contain orthoclase, which ·increases greatly in amount toward the centre, but all are devoid of quartz. The stock has been injected into a steeply folded series of volcanic flows, breccias, and tuffs that strike more or less parallel with the major axis of the stock. On its northeast side the stock is flanked by a band of fairly coarse volcanic breccia of andesitic composition and ·having fragments up to several inches in length. Where this breccia is tangential to the stock it is both dynamically and chemically metamorphosed to a marked degree, and within the zone of this metamorphism are enclosed the copper deposit~. The ore consists of bornite, chalcopyrite, and a little magnetite occurring as disseminated grains and small veinlets in the metamorphosed breccias. The only gangue minerals are orthoclase, albite, oligoclase, and biotite. The two most common vein minerals, quartz and pyrite, are conspicuously rare or absent. The dynamic metamorphism has produced two well-defined structures, namely, a strong schistosity parallel with the curved vertical contact of the stock and a very striking set of small, straight, nearly parallel open fractures that stand nearly vertical and at right angles to both the schistosity and the stock contact. These are called the ore fractures."

Jan 1, 1954

By H. R. Kempthorne

"The Property of Bevcon Mines Limited, including a recently acquired adjoining south group, occupies an area of 2,625 acres in northeast Louvicourt township, Abitibi county, Quebec. It is situated 17 miles east of Val d'Or at the junction of provincial highways 58 and 59.Gold was first discovered in the area in 1931 by the late S. B. Jowsey on the present property of Buffaddison Gold Mines adjoining to the west. However, it was not until the winter of 1944-45 that diamond drilling encountered encouraging results on the Bevcon claims. During the period 1946-1948 a shaft was sunk to 1,000 feet and considerable development undertaken from the 500-foot to the 1,000-foot levels. Between 1947 and 1950 approximately 24,000 tons of dump ore and 48,000 tons of ore by stoping were milled at Perron Gold Mines. The favourable results of these tests prompted the decision to construct a milling plant at Bevcon. The mill began operating in July 1952, and presently has a capacity of 800 tons per day. In 1953 the shaft was deepened to 1,600 feet and is currently (1955) being driven to 2,225 feet.Total production of gold to the end of 1954 has been 101,024 ounces from the milling of 697,427 tons of ore of an average grade of 0·163 ounces per ton.GeologyThe Bevcon orebodies occur in a granodiorite stock which has an east-west length of approximately 4 miles and a maximum width of 1 1/2 miles. The property covers the central portion of the stock and its contacts with the Keewatin volcanics. Approximately one-third of the northern contact and one-half of the southern contact are contained within the Bevcon claims. The granodiorite has been cut by acid (feldspar porphyry) and basic dykes trending east-west. A younger diabase dyke, 300 feet wide, strikes northeasterly across the property 1,000 feet east of the shaft.The main ore zone, striking east-west, lies between the more northerly porphyry dyke and the north granodiorite-greenstone contact. It has been extensively sheared, fractured, altered, and mineralized by gold-bearing solutions. It is approximately 2,000 feet Jong from the west boundary towards the diabase dyke. The shaft is centrally located and passes through the south contact of the ore zone at the 500-foot level. The zone increases in width and trends northerly with depth, due to the porphyry and greenstone contacts having average dips of 80 degrees and 70 degrees respectively to the north. Thus on the uppermost or 500-foot level the width is 150 to 200 feet, and at the present bottom level at 1,600 feet the width is 400 to 500 feet.Another gold-bearing zone has been indicated 200 to 400 feet south of the main ore zone by limited surface drilling."

Jan 1, 1949

By E. Marcotte

"Technology developments and improvements are imperative to maintain a viable mineral processing industry. In order to achieve optimum implementation of technology in processing plants, safety conscious and efficient work forces are required. Effective management methods are required to prevent employee injuries, equipment or environmental damage and process losses. Good leadership also provides for employees to perform their work in the safest and most efficient manners to attain optimum recoveries of the valuable minerals and produce high quality mill products. Equipment and processes must be designed, operated and maintained as required to assure safe and efficient mineral processing.INTRODUCTIONThe Canadian mining industry must contend with many challenges to attain and maintain a competitive position in today's global market. Canadian Mineral Processors play a vital role in meeting the challenges and achieving optimum mineral productivity.Ongoing technology developments and improvements continue to be imperative to maintain a viable mineral processing industry. The efficient implementation of technology developments requires a safety conscious, skillful and productive work force.In addition to technical and human resources, challenges may also include governments, labour unions or environmental advocates who at times may appear to be misguided or unrealistic. Canadian Mineral Processors must not allow themselves to be overwhelmed by these apparent obstacles but must use their demonstrated ingenuity to achieve successful solutions.It should be recognized that the majority of the Canadian work force are, in fact, a potentially talented and skillful people with ambitions to excel. As leaders of people, we must provide the methodology, incentive and direction that will allow our work forces to realize their ambitions. If the potentials of our work forces are not recognized and leadership is not properly exercised much loss will occur. That is, safe effective and efficient work will not be achieved."

Jan 1, 1993

By S. A. J. Hopper

"The Golden Manitou mine is in the northeast quarter of Bourlamaque township, Abitibi county, Quebec. During the summer of 1937 a body of gold-silver-zinc ore was outlined in a series of diamond drill holes located to the west of an old copper-zinc showing in the property of Quebec Manitou Mines, Limited. In 1938, a shaft was sunk and the orebody further explored from levels at depths of 210 and 360 feet.In 1941 the western half of the Quebec Manitou property was acquired by a new company, Golden Manitou Mines, Limited, and the installation of a mining and milling plant was at once undertaken. Milling started in August 1942. The following is a summary of production to December 31, 1946:The orebodies are sulphide replacements in a sericite schist shear zone. They vary in width from 8 feet to 65 feet and range in length up to 850 feet . Much of the ore is of the 'massive sulphides' type . The sulphide minerals in the ore are pyrite and sphalerite with minor quantities of .galena, tennantite, chalcopyrite, and arsenopyrite. Native silver (as wire and leaf silver) has been found in vugs and as coatings along fractures. In one section of the mine a few specks of gold were observed. Spectrographic analysis of ore samples has indicated the presence of zinc silicate."

Jan 1, 1954

By Jorgen Elbrond, Yve Lizotte

"A mine evaluation method based on the use of a computer program that models mining with an open-ended dynamic program is presented in this paper. It is demonstrated with an example how the method is applied, how some of the decision variables are related in the particular industrial environment and how these decision variables affect the economic benefits of mining.IntroductionTwo distinguishing characteristics make mining a particular industrial environment: exhaustible resources of a given ore deposit and heterogeneousness of the ore grade spatial distribution in the ore deposit. These characteristics, inflation, uncertainty and cyclical price variations which greatly affect estimated cash flows also contribute in rendering difficult the evaluation of the economic outcome of mining at the preliminary planning stage.Decision variables and their ranges are associated with the mine plan; basically, they include choices of the mine's nominal capacity (mining and milling), the sequencing of mining through the deposit, the ranges of possible production rates and cutoff grades, and the stockpiling policies. The mine's nominal capacity must be decided at the planning stage, but this capacity choice must take into account flexibility to modify other decision variables as mining commences and uncertainty resolves.Although it is generally accepted in discounted cash flow analysis that the sequence of mining must proceed from the richest to the lowest-grade stopes (with correspondingly ajusted cutoff grades), this may not produce optimum benefits when cyclical price variations are considered.Mining rates and cutoff grades can also be adjusted to changing economic conditions, taking into account the limited resources of the ore deposit. Thus, when prices are thought to be in the trough of a cycle, production can decrease to preserve ore for expected greater future profits. When prices rise, mining rates can increase possibly even over the mine's nominal capacity. In both cases, the machinery's effectiveness shall not be-optimally utilized; this will be reflected particularly by the variations in the concentrator's metal recovery and the concentrate grade output."

Jan 1, 1982

By Lynn C. Fister

"Coal is rapidly becoming a major alternative to oil. According to the World Coal Study Final Report, total world coal trade could approach one billion tons annually by the year 2000. To facilitate the increased production and export market potential of the coal producing countries, advancements must be made to improve the transportation systems. Coal slurry pipeline systems could play a significant role in achieving these market forecasts.There are three major components to a coal slurry system the preparation plant, the pipeline and the dewatering plant. The experience and expertise gained from the Consolidation Coal Company system in Ohio, the Black Mesa system in Arizona and ETSI's Coal Evaluation Plant demonstrate that slurry pipeline technology is proven and available to meet the coal transport challenge.The costs of transporting coal by slurry pipeline can offer significant savings, as about 70 per cent of its costs are fixed. The reverse is true for railroads, where 75 to 80 per cent of the costs vary with inflation. All forms of transport-rail, barge and pipeline-will be required to move the massive volumes of coal. Coal slurry systems can provide a viable transport alternative.IntroductionThe importance of coal as a major alternative to oil is now well known and accepted throughout the world. Increasing oil prices over the last eight years have had a serious effect on national economics, particularly in those countries that are heavily dependent on oil. Coal can replace oil as the principal fuel source which could support world economic growth over the next two decades. This is the main conclusion of the World Coal Study (WOCOL) Final Report, published in May 1980.The product of that report was a result of considerable deliberation by key industry leader s and energy experts. The underlying message of the World Coal Study is that our energy and economic problems can be faced with confidence if coal use doubles by the early 1990s and triples by 2000, and if steam coal trade expand s considerably."

Jan 1, 1982

Overview of Presentation Why Enter Agreements with First Nations Making it Win-Win ?The Principles The Process Making the Process Work Resource Agmts Defined Resource Agreements are legally binding agreements between a resource company and the First Nation(s) whose Aboriginal or Treaty rights may be impacted by the activities of the proposed project

May 1, 2009

By Changping Hu, Keqin Tan

In 1937, the Metallurgical Department of the National Resources Committee established a copper refinery plant (predecessor of the Chongqing Smelter) in Changsha, Hunan Province, China. The blister copper produced by a local copper smelter was casted as anode for electrorefining. The plant, with a capacity of one ton of electrolytic copper per day, was designed and tested in 1937. At the trial production stage, a total of 9 tons of cathode copper was produced. The plant was formally put into operation in July 1938. In the same month, more than 20 tons of electrolytic copper with purity over 99.9%Cu was produced. This was the first batch of electrolytic copper produced in China. In 1939, China’s largest non-ferrous metal smelting plant, Fengtian Gold Mine Refining (predecessor of the Shenyang smelter) was completed and put into operation in Shenyang, mainly producing nonferrous metals such as gold and silver, as well as copper and lead. In 1939, the Kunming copper smelter (predecessor of Yunnan Smelter) was completed and put into operation. The plant equipment, imported from the United Kingdom, was designed to produce 1,200 tons of electrolytic copper annually. In 1943, Jiatong smelter (predecessor of the Shanghai Smelter) became the 4th domestic cathode copper producer. Since 1949, China has gradually established a large copper industry. These developments are discussed in this paper. Today, China operates nine out of the twenty largest copper refineries in the world. With a total capacity approaching 9 million tons of copper per year, China has the world’s largest copper refining capacity. INTRODUCTION China is a country with a long history of copper mining. The earliest smelter in China in recent times was the Shanghai Smelter, which was built in 1912. From then until 1949, China successively built Chongqing Smelter, Kunming Smelter and Shenyang Smelter. The world's first copper electrorefinery was the Pembrey refinery built in the UK in 1869 (Lu, 1999). However, it was not until 69 years later that the technology was spread to Changsha, China.

Jan 1, 2019

By D. A. Peterson, R. Pakalnis, G. Peter Mah

"Laboratory and trial installations have been completed to determine the potential of composite cable bolt reinforcement in Canadian underground mines. Several prototypes of glass fibre cable bolts have been developed and tested, two of which are currently available to the mining industry. Their evalualtion consisted of lab testing in Canada and the United States, along with trial installations in several underground mines throughout Canada. The objective was to develop a cost competitive composite cable bolt equivalent in strength to that of a 16 mm (Ys in.) diameter steel cable bolt. In addition to achieving equal or superior load carrying characteristics in tension, the glass fibre cables generally experienced an increase in the rate of installation due to their lighter weight. Unlike conventional steel cables, composite cables may be installed within mines which utilize continuous excavation and which require cuttable support. A market analysis of cable bolt usage in Canada has been completed. Glass fibre cable bolts are an effective means of rock reinforcement in mining applications. They prove to be a viable alternative to conventional steel cable bolting. IntroductionCurrent cable bolting practice consists of cement grouting one or more steel cables within a drill hole in order to support the surrounding rock mass. Cable bolts are a form of internal support and are generally used as pre-support in open stope and cut-and fill mining methods. They can be either tensioned (active support) or untensioned (passive support) and may be of any length, though for underground mining applications, are generally less than 20 m (65.6 ft) and are untensioned. A major advantage of cable bolts is that they are flexible and can be coiled to approximately 1 m (3.3 ft) diameter coils. This allows relatively long lengths (>20 m, [65.6 ft]) to be installed in areas with limited head room (1.8 m)."

Jan 1, 1994

By G. Lafont

Aug 1, 2013

By Simon Houlding

"Part 1 (CIM Bulletin, August 1991) of this article identified the limitations of the traditional modelling methods and demonstrated the approximations and errors introduced by their application to complex mining situations. The objective of Part 2 is to describe the evolution of new, proven technology which eliminates these deficiencies and provides precise and practical alternatives. These promote the use of realistic geological and mining shapes and eliminate altogether the rectangular approximations of traditional methods. Limitations of the Traditional MethodsThe limitations of the traditional modelling method s (viz. simple block modelling, gridded modelling and their more recent variations) were discussed in detail in Part I . These methods are all based on the use of rectangular discretization to represent the boundaries and volumes of ore deposits and mining excavations. As a result they are unsuited to the representation of nonrectangular geological complexities such as folding, faulting and irregular surfaces . They are equally unsuited to the representation of realistic excavation limits, particularly in the case of underground mining.Recently these methods, with limited variations in technique, have been applied to increasingly more complex geological and mining situations. The resulting potentials for error and conflict within the modelling pro cess were demon strated in Part I . The effects can be summarized as follows:• volume and boundary approximations introduced by therepresentation of irregular three-dimensional boundaries andvolumes by rectangular modelling elements ; • geostatistical errors and conflicts caused by neglect of the relationships between grade estimates and the geometric/ spatial aspects of irregular volumes and associated observations (samples), including an inability to produce precise estimates with meaningful confidence limits;• a compounding of these effects by using rectangular element sizes other than the geostatistical optimum, and by using differentelement sizes within a model; and• general inefficiencies introduced throughout the modelling pro cess by the requirement to represent geology, grade distribution and excavation limits with a singular modelling method and model."

Jan 1, 1991

By Yongquan Zhu, Zhengguo Zhu, Zhichun Liu, Chao Kong, Xinqiang Gao

"The aim of the study is to have a good understanding of the change in the seepage field during and after the tunnel excavation in weathering alteration rock. Field tests are used to monitor the changes of the water table and the numerical model is used to analysis the influence of the seepage filed with different operation conditions during and after the tunnel excavation. Results indicate that the depth, diameter and pumpage of precipitation well are the main factors that have a great influence on the drainage effect. Results also indicate that different operation conditions had various effects on the decrease in water yield during tunnel construction and the recovery in groundwater level after construction.INTRODUCTIONAs a potential disease during tunnel construction, Gushing water not only affected construction schedule, increased construction cost, as well as affected tunnel stability and safety during operation, but also decreased ground-water level. What’s more, the fall of water table caused by gushing water in tunnel would have influenced surrounding residents’ living water, agricultural water and ecological environment around tunnel. In recent years, enough emphasis has been paid to the influence on environment due to the construction of tunnel as a result of the reinforcement of people’s environmental protection awareness.As a result of water collection and drainage after excavation, groundwater was discharged into the tunnel, which caused a loss of water resources in the adjacent mountain mass. Furthermore, during tunnel operation, it was difficult for groundwater level to resume its original condition, which caused a bad ecological environment, because drainage system during tunnel construction destroyed its original hydrologic dynamic balance.In order to study whether decreased groundwater level resulting from tunnel construction could be restored during operation to its original condition, this paper gave a field monitoring on tunnel displacement during construction and simultaneously, generalized model of regional hydrogeology was created according to field hydrogeology to carry out a calculation of stable seepage flow and draw comparisons between recovery conditions of various water levels."

Jan 1, 2015

By P. Karimi, A. Amini, H. Abdollahi, A. Mirzaeian

Due to detrimental effects of cyanidation process on the environment in gold industry, application of cyanide alternatives such as thiourea are being highly considered in recent projects. In this study, the extraction of gold from poly metal ore, using thiourea was precisely investigated. The representative sample contained 2.5 ppm Au and 160 ppm Ag. The sample was categorized as oxide gold ore, because the main part of its pyrite was changed to iron oxide and hydroxide such as goethite and lepidocrosite. According to mineralogy, the main gangue mineral was quartz. It shows that gold grains are free and interlocked with quartz matrix. Also, the presence of a high amount of silver in free and sulfide forms and also the low content of other sulfide minerals such as base metal sulfides is a remarkable point of these studies. In the gold extraction process with thiourea, there are several parameters that affect the rate of gold dissolution such as concentrations of thiourea as a gold lixiviant and ferric sulfate as an oxidant, pH and size fraction of feed and leaching time. The influence of these parameters on the gold dissolution rate were investigated and optimized. The results showed that the concentration of thiourea is the most influential parameter which could increase the gold recovery to 71% (at 10 g/kg sample). The optimal amount of ferric sulfate was determined as 6 g/kg sample. Also, the optimal levels of size fraction of feed and pH of solution were 88% under 75 micron and 2 as acidity; respectively. Leaching time was 6 hrs. In addition, this sample was leached with cyanide and the optimized values of size fraction of d88=75 microns, pH=10.45, 2500 ppm of sodium cyanide with time leaching of 24 hours were concluded for maximum recovery of gold in solution. Finally, the results of cyanidation tests were compared to the thiourea dissolution after optimizing all affected parameters in cyanidation process.

Jan 1, 2016

By Andrew L. Mular, Robert P. Edwards

"The operation of flotation circuits is often regarded as a combination of art and science. Expert systems offer a method by which the art may be captured and supervisory control of flotation circuits fully realized. Operating knowledge, the art, can be consistently employed to enhance regulatory control through the judicious application of an expert system. Using an expert system, a supervisory control routine was developed, and success- fully implemented, in the copper flotation circuit at Brenda Mines Ltd.The expert system ran in conjunction with regulatory PI controllers on a personal computer. The expert system received assays via an on-stream analyzer and adjusted regulatory loop set points as required in real-time. From its commissioning in November, 1989, to the end of the mine 's operation in June, 1990, it was enthusiastically embraced by the operators and attained operating levels superior to those achievable manually.IntroductionExpert system (ES) software springs from research into artificial intelligence and is currently making significant inroads into business and industry. ES proponents make many attractive claims; they are a means of capturing the knowledge of experts and they can be programmed by non-programmers. To date, most uses of this software in the process industry are in off-line applications, meaning that the applications are not tied directly to operating (on-line) environments. Moreover, in on-line environments, they are typically employed as advisors and only suggest changes. Human operators are required to close-the-loop to the process. Yet, an ES should be applicable to operating environments and, if the claims of the proponents are valid, should also be better than existing tools. As an intelligent controller an ES must use the knowledge of experienced operators, apply it directly to a process and do this without the intervention of human operators. On-line applications have been successfully employed in the closed loop control of SAG circuits (Herbst et al., 1989) and flotation circuits (Hales, 1989). Harris and Kosick (1988)detail an implementation for flotation control at the Polaris Mine."

Jan 1, 1992

By J. Lee, R. G. Rosehart

"The basic problem of arsenic contamination from mine water is discussed. Effective methods of removal involving chemical precipitation, activated carbon adsorption, ion exchange and reverse osmosis are discussed. As well as an economic analysis, detail is also paid to other ions in solution which are removed simultaneously.INTRODUCTIONThe object of this paper is to review arsenic and its removal from gold extraction plant effluents. The first method considered is chemical precipitation. A second method is sorption processes, such as ion exchange resins and activated carbon adsorption. A third method is the possible application of reverse osmosis for the treatment of mine waste waters containing arsenic.Arsenic pollution in the gold mining communities of Canada and Ghana have been extensively studies (l, 2). Lynch(3) Shabunin, Gutman and Kogan( 4), Hollo, Troth, Vennes and Illinigi (5) and Hau(6) have reported their removal methods of arsenic by chemical precipitation, ion exchange and biological methods. Their conclusions were that the precipitation with Fe2+ and Fe3+ ions was most effective.Scope of the ProblemInitial aspects of this research program involved a detailed analysis of the operation of a gold extraction plant located in Canada. The name and location of the mine is proprietary information. Figure 1 gives a basic process schematic with the main tailing streams identified.Table 1 gives information as to the various mine streams and their physical and chemical composition. In this study, primary attention is paid to the removal of dissolved arsenic from waste waters. Solids from this type of operation can always be back-filled. As could be anticipated, the dissolved As content of the primary flotation tailing stream is very low. The dissolved As level in the secondary processing stream and the roasting quench water is quite high. The reason being that at this stage of the process, the arsenic has been freed from the arsenopyrite forms."

Jan 1, 1972

By D. M. Morrison

"Microseismic systems at five mines in the Sudbury Basin provide the basic data for Falconbridge Limited's rockburst research. Daily and long-term analysis of this data as well as underground observations has confirmed the fault-slip mechanism of rock bursting at three mines. A detailed analysis of the complete history of Falconbridge Mine is being conducted and Distinct Element numerical models are being used to simulate both the stick-slip behaviour of faults and the dynamic effects of the induced vibrations on rock and backfill. University research includes acoustic tomographic imaging of the rock mass based on seismic wave propagation and collection of full micro seismic waveforms to allow application of advanced seismic and statistical analysis techniques. INTRODUCTIONFalconbridge Limited currently has five mines operating in the Sudbury Basin: East, Lockerby, Onaping, Fraser, and Strathcona Mines, which along with the Falconbridge open pit produced 2.8 million tonnes of ore in 1986. The underground mines range from about 600 m to 2000 m below surface and one of the consequences of mining at these depths is the occurrence of rockbursts.Research into rockburst phenomena at Falconbridge began over 25 years ago and research is continuing in an effort to avoid the problem by improved mine design, to protect mine openings from damage by design of effective support systems and to better understand the processes which precede a major fault slip rockburst. Since the early 1980s, significant progress has been made due principally to micro seismic monitoring and advances in microcomputer technology coupled with detailed underground investigations.It is now possible to identify the fault-slip mechanism as the cause of many of the rockbursts which occur at Falconbridge mines. By gaining an understanding of effect of mining-induced stresses on the pre-existing geological structures, areas which may experience rock bursting can be identified and can be protected against severe damage by appropriate support techniques."

Jan 1, 1989

By Christopher Boys

"Many water inflows in Saskatchewan potash mines are linked to salt anomalies. Potash ore and three anomalies in the PCS Cory potash mine in the Patience Lake Member of the Prairie Evaporite Formation were studied to understand the processes involved in their formation. Another goal was to find geological indicators of the proximity of anomalies. A geological model that relates the potash to the salt anomalies has been developed.Up to five post-burial facies may be recognized. These range from carbonate-mud collapse breccias to bedded sylvinite, and probably result from post-burial leaching. In this model, the same fluids that caused widespread recrystallization and possibly enrichment of the potash salts, started by dissolving huge cavities in the evaporites. The effects of the leaching were highly variable, indicated by selectively preserved delicate laminae and chevron textures, to deformed and totally dissolved salt beds. In at least two major events, Late Devonian and Cretaceous, collapse structures may have acted as conduits for overlying formation waters to cause pervasive leaching and recrystallization of the Prairie Evaporite Formation.Geological indicators of the proximity of an anomaly may include: a change in insoluble seam color from greenish-gray to mottled brown and greenish-gray, unusual local increases in ore grade, large patches (e.g., >200 cm2) of sylvite-poor potash crosscutting units near the top of the ore wne, and drops in topography > 10 m of the marker seams. Anhydrite was more common in an anomaly than in ore. The local abundance of anhydrite in ore may indicate the proximity of some salt anomalies. Once an anomaly has been encountered, indicators of a major collapse feature may include: stretched clay seams, folded beds, small collapse features (1 m to 20 m), numerous washouts, or split clay seams with injected salt. Any number, or none, of these indicators may be found close to a major collapse feature."

Jan 1, 1993