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By Gordon Sparks, Lyle Kajner

"An often over-looked component in the assessed value of a mining property is the value derived from the ability of the operator to limit financial losses during adverse economic times (i.e. low market price, high energy prices, etc.) by suspending operations. Overlooking the value of this type of operating flexibility when conducting mine investment analysis may negatively bias the risk profile for the investment by over estimating the investment's downside potential, thereby effectively undervaluing the investment. This paper illustrates the nature of the value of operating flexibility and discusses how it may be explicitly quantified within the context of conducting stochastic mine investment analysis. IntroductionMining properties are evaluated using an array of techniques ranging from simplistic non-discounted payback calculation s to sophisticated, discounted-stochastic simulation. Stochastic simulation analysis is perhaps the most robust mine investment analysis technique as it not only provides an estimate of the expected value of the property, but also quantifies the associated risks (for examples of stochastic mine investment analysis, see: Billingsley and Yaychuk, 1986; Gentry and O'Neil, 1984; Munro, 1977; or Harris, 1970).The quantification of risk is important as it provides the necessary yardstick required to allocate the corporation's resources efficiently. Resources are said to be allocated efficiently when the corporation's expected long-term financial reward is maximized while at the same time minimizing its risk (see Hertz, 1968; or Markowitz, 1952 for in depth discussions on efficiency as it relates to investment policy). The efficient allocation of resources should be the objective of any rational corporation. Therefore, rational corporations should employ stochastic evaluation techniques when screening their investments."

Jan 1, 1992

By A. David MacPhail

"Highland Valley Copper is a large volume producer of copper and molybdenum concentrates. Production is by conventional truck and shovel operation combined with an extensive ore handling in-pit crushing and conveying system.Grade of the two orebodies is low at 0.4% copper and 0.007% molybdenum and this demands a production rate in excess of 260 000 tpd at a stripping ratio of 1: 1. Mining cost has to be kept at minimum levels to keep the mine profitable and thus, it is necessary to keep in the forefront: of technology. As well as the in-pit crushing system, the mine has pioneered the use of shovel weighing coupled with a state-of-the-art dispatch system.Maintenance of the equipment is carried out at the on-site mine maintenance shop with assistance from local shops for engine and wheel motor rebuilds and other large jobs such as those requiring stress relieving. Shovel and truck rebuilds are undertaken by mine crews. Both long- and short-term planning is designed and scheduled in the mine engineering section. Outside consultants are used to assist in slope design, reclamation and blasting technology."

Jan 1, 1992

By J. E. Zajic, E. A. Sullivan, T. R. Jack

"The release of vanadium, iron, nickel and titanium from the cokes produced in the upgrading of Alberta oil sands bitumen has been assessed for simple chemical leaching processes. Flexicoker coke (Exxon Engineering and Research) has been found to be quite amenable to the recovery of vanadium as well as nickel, iron and some titanium by these techniques, whereas fluid coker coke (Syncrude) and delayed coker coke (Great Canadian Oil Sands) are relatively intractable under the mild conditions employed. The factors affecting the extent of vanadium release are discussed in terms of the surface area accessible, the wettability of the material, and the chemical and physical composition of the coke particles in each case.A novel biologically assisted heap leaching procedure for f1exicoker coke is also described, based on the growth of the chemolithotrophic bacteria, Thiobacillus thiooxidans A TCC 8085, on elemental sulphur added to the coke."

Jan 1, 1980

By A. Galibois, R. Singhal

"This paper highlights some of the potential application areas of knowledge-based systems in the mining industry. The basic theoretical principles associated with knowledge-based systems are discussed and the justification for mining applications is given. The paper concludes with a brief description of a prototype knowledge-based system applied to scraper selection that was developed at Université Laval on a LISP machine. IntroductionThe beginning of Artificial Intelligence coincided with the conception and development of the first computer systems some thirty years ago. At that time researchers were euphoric about the possibility of modelling the human reasoning process. Soon, however, they discovered that the combinatorial aspect of the set of possible solutions to a particular problem did not permit an in-depth evaluation.In the mid-60s researchers started to look at the heuristic approach because it was more suited to human behaviour with its congnitive abilities (i.e. representing, reasoning, problem solving and advising). The heuristic approach allows possible results rather than exact solutions and it is more rapid and cost effective than the exhaustive combinatorial analysis. The heuristic approach did allow some noticeable progress in the seventies with the development of the first expert system called MYCIN with the objective of diagnosing blood infection diseases."

Jan 1, 1988

By Sabine Noelte, Mikko Petteri Rantamäki, Christopher Robben, Anssi Takala, Karl-Erik Rånman

"Sensor-based ore sorting is on its way to establish as a standard option for physical separation. The increasing number of installations in coal, iron ore, industrial minerals and hard-rock metal mining segments underlines the technological and financial potential that is beginning to be untapped. The Ma’aden Phosphate installation with 1.650 t/h sensor-based ore sorter feed sets a new benchmark for the possible capacity of stationary installations. Besides stationary installations, including multiple sorters parallel in different size ranges and multiple stages, containerised semi-mobile plants are applied. These offer two advantages, first being the reduction of transport costs when applied close to the mining face. The second is that semi-mobile systems enable processing of tens of thousands of tonnes of ore in a piloting phase with an approximate duration of 0.5 to six months, verifying the results laboratory mini-bulk tests on 5–10 tonnes of sample. This is especially important for low-grade metal ores because of the inherent Fundamental Sampling Error, as well as the Grouping and Segregation Error. The paper elaborates the results achieved within the I2MINE project, treating polymetallic ore at the Boliden Concentrator in Sweden.INTRODUCTIONSensor-based ore sorting (SBS) is becoming a standard option for physical separation, applied in all segments of mineral production. The Umm Wu’al project sets the bar for stationary SBS installations with 1,650 t/h feed (TOMRA, 2015). TOMRA Sorting Solutions has finalised an agreement in cooperation with Outotec to supply Outotec-branded sorting solutions for the mining and metallurgical industry (TOMRA, 2014). Especially for low-grade hard rock metal ores, an interdisciplinary approach is necessary applying experts for all aspects of mineral production. Due to the impact on the whole process stream, it is important on the end user side to have high level managerial support and involve all disciplines to ensure that all stake holders are involved in the analysis."

Jan 1, 2016

By A. McIntyre, L. R. Plitt

Both the Bond and the Hardgrove grindability tests are widely used in the mineral industry to measure the ease of the comminution displayed by a material. The Hardgrove test is mainly used for coals, whereas the Bond grindabifity test is mainly applied to hardrock minerals. The Bond grindability has the advantage that it can be empirically related to the energy required for comminution (work index), whereas the Hardgrove grindabifity test has the advantage of being easier to perform. In an effort to establish a valid correlation between work index and Hardgrove grindability, a series of parallel grindability tests were carried out on a wide variety of rocks and minerals. The standard Hardgrove test was modified to allow for materials with a higher density than coal. A new, satisfactory relationship was established which permits rapid estimation of work index from Hardgrove test data.

Jan 1, 1980

By A. G. Pronk, D. M. Burton

"A regional till sampling program in the Upsalquitch Forks-Tetagouche Lakes area, centred some 70km west of the city of Bathurst, has proven an effective method for gold exploration in the heavily glaciated interior of northern New Brunswick. Prospecting activities within this area over the past three years, have led to the discovery of several gold occurences associated with quartz-carbonate alteration in a variety of intrusive rock types emplaced along major fault zonesQuaternary mapping shows that the glacial history is complex. However, the displacement of material is uniform in distance and direction, and the till is generally thin (0.5 m to 2.0 m) and locally derived, making the interpretation of till geochemical patterns relatively simple for the explorationist. Previous studies have shown the the fin e-grained gold is best detected in the -250 mesh (-0.063 mm) till fraction (clay plus silt) and that the C-horizon is the preferred medium for analyses.Samples were collected on a 2 km grid and analyzed f or Cu, Pb, Zn, Au, Ag, As, Sb, Mn, Fe, Ni, Co, and Cd. Results indicate that concentrations of 10 to 20 ppb Au can effectively delineate areas of anomalous gold in bedrock associated with fault structures, and that a good potential for discoveries exists to the west of the known occurrences, where up to 678 ppb A u has been detected in tills. IntroductionThis paper reports on the result s of surficial geological investigations conducted over the past two field seasons in north-central New Brunswick. The stud y area is located in the Upsalquitch Forks-Tetagouche Lakes map area s (N.T.S. 21 0 19 and 21 0 (10) 70 km west of the city of Bathurst (Fig. I). The area is situated on the margin of the New Brunswick Highlands and has a maximum elevation of 640 m (for a detailed description of the physiography, see Rampton et al. 1984).Historically, exploration in northern New Brunswick has concentrated on base metals within the Cambro-Ordovician Tetagouche Group, resulting in the discovery of man y significant massive sulphide deposits (Brunswick No.6 and No. 12, Heath Steele, Caribou, Armstrong Brook, Orvan Brook, McMaster, Murray Brook, and Restigouche). Auriferous base metal occurrences along the Rocky Brook-Millstream Fault have also been previously investigated."

Jan 1, 1988

By John H. Schloen

"The object of this paper is to review electrolytic copper refining as it was in 1954(1), as it is now in 1984, and to comment on the many improvements which have been made in the last thirty years.In 1954, and even in 1984, the ASTM specification B 115 for cathode copper was 99.90% minimum copper plus silver content and 100% minimum electrical conductivity, IACS standard. However, to meet competition and to satisfy the requirements of the fabricators and the electrical industry, the electrolytic refinery must supply a product of 99.95% to 99.96% minimum copper content, and 101fJlo minimum electrical conductivity.The range of cathode impurities reported by 20 major copper refineries in 1954 are given in Table I.The much more rigid British Specification, DD 78, for high-purity cathode copper, specifies individual elements, as well as groups of elements, as shown in Table 2.The Svenska test has been replaced by a similar procedure which uses 2.r mm diameter wire. The ISO test is the one listed in the DD 78 specification. In Table 3, corresponding values for the Svenska and ISO test s are given for various wire bar coppers."

Jan 1, 1986

By Robert B. Parsons

"The annual onslaught of provincial budgets and tax changes is complete, and once again the Canadian taxpayer is being asked to dig deeper into his pocket to fund old and new programs. It is noteworthy that 1987 tax reform promised lower taxes, but a broader fax base. Five years later, we still have the broader tax base, but the lower faxes have gradually crept up to pre-tax reform levels. Surprise! Surprise!IntroductionThe last edition of Tax Notes commented on some important proposals announced in Manitoba's 1992 budget. In this issue, Tax Notes summarizes the 1992 budget proposals of British Columbia, Ontario and Quebec. These budgets reflect the continuing trend of transferring responsibilities and the related costs-from the federal government to the provinces. As well, the budget papers bear witness to the respective governments' political stripes. British Columbia, Ontario and Quebec are seeking higher tax revenues. Only Quebec continues to acknowledge the importance of the mining industry in its annual budget documents."

Jan 1, 1992

By A. J. Keen

"Cominco's Polaris Mine is an underground lead/zinc operation located on Little Cornwallis Island in the Canadian High Arctic. Polaris is the world's most northerly base metal mine, situated at about latitude 75°N and longitude 97°W (Fig. 1). The closest community is Resolute Bay about 100 km to the southeast.During the construction and development phase Cominco adopted a unique scheme to save time and money. Many facilities including concentrator, powerhouse, shops and warehouse were built on a barge in southern Canada. The barge was towed 4800 km to the site in August 1981. Production at Polaris began in November 1981. The current mining rate is 1 million tonnes per year. The mine employs 250 people with about 190 on site at any time.GeologyThe deposit is a Mississippi Valley type orebody and lies near the top of the Ordovician Thumb Mountain Formation. Ore minerals consist of sphalerite and galena with the gangue being predominantly dolomite with calcite and marcasite. The orebody is situated completely within permafrost, consequently the voids frequently found in the ore are filled with ice. The orebody strikes north-south, dips approximately twenty degrees to the east and takes up an area about 400 m wide by 700 m long. The upper portion of the orebody (60 m to 150 m below surface) lies in an area called the Panhandle Zone. The deeper portion of the orebody known as the Keel Zone extends to 300 m below surface (Fig. 2). The deposit is strongly zoned with a high grade zinc/lead and iron-rich tabular core overlain and underlain by vein, stringer and breccia mineralization. The ore reserves at January 1991 were 14.6 million tonnes at 3.6% Pb, 13.7% Zn, 3.2% Fe, after producing 8 million tonnes at 3.9% Pb and 14.2% Zn since November 1981"

Jan 1, 1992

By M. Cossette, V. H. Tran

"How can the durability of asphalt pavement be doubled without increasing highway budgets? Asphalt containing asbestos can provide the desired performance with additional costs being made up by longer life. The addition of a low percentage of asbestos to an asphalt mix permits a higher asphalt content without any consequent loss in stability. It is mainly the higher asphalt content that provides improved performance and durability, although the fibrous reinforcement plays a key role in preventing the propagation of micro-fissures. As well, several international studies show that, thanks to the latest production techniques, no environmental hazards need be incurred.RésuméComment doubler la durée des chaussées d'asphalte sans augmenter les budgets de voirie? L’asphalte contenant de l'amiante peut offrir les performances souhaitées et l'augmentation des couts initiaux peut être rapidement compensée par une durée prolongée. L’addition d'une faible teneur en amiante courte il l'enrobe de bitume permet des teneurs en bitume plus élevées sans subir une perte de stabilité en conséquence. C'est principalement la teneur accrue en bitume qui assure un améliorations propriétés physiques et une augmentation des performances mécaniques, ainsi qu'on prolongement de la durée. Cependant, le renforcement fibreux joue un rôle clef en prévenant la propagation éventuelles micro-fissures. Les nouvelles techniques évitent tous risques environnementaux"

Jan 1, 1991

By Kosta Fytas, Nour-Eddine Chaouai

"Selection of the appropriate kriging plan during indicator kriging estimations is of a paramount importance to the precision of ore reserve estimation. However, very little is known on the sensitivy of indicator kriging results when changing the kriging plan parameters (mainly search distance and number of samples). This paper evaluates the effect of the search distance and number of samples on indicator kriging results using a gold deposit as a case study.IntroductionBlock estimation using kriging is based on the autocorrelation function (variogram) on one hand and on the kriging plan on the other. As far as the variogram is concerned it is more or less subjectively adjusted and this is reflected on its parameters (range, sill, nugget effect and anisotropy). The effect of a poor estimation of these parameters on the kriging variance of ordinary kriging has been proven very important (Brooker, 1986). Choosing a kriging plan is generally a difficult matter depending on the estimation type (global or local). Generally there is not a unique kriging plan be cause there is not a unique structural analysis (variogram). There are no rules or dogmas in choosing a kriging plan but it is rather a function of the sampling pattern (David, 1982).Structural analysis requires the hypothesis of quasistationarity but very often either the data available within the zone of quasi-stationarity are too many so that the search distance is reduced during kriging or the data are too few to satisfy a stationary kriging system (Journel and Huijbregts 1978). As a rule, the larger the neighbourhood, the more precise the estimates should be , but for large neighbourhoods the hypothesis of stationarity does not always hold (Rivoirard 1987; Armstrong and Champigny 1989)."

Jan 1, 1991

By David A. Grieve, David E. Pearson

"A rank-map of Crowsnest coalfield, showing the distribution of the bituminous coal measures and the locations of major structures, has been produced from vitrinite reflectance measurements on over600coal samples. The timing of coalification in relation to these major structures has also been determined.In the west-central portion of the coalfield a complete stratigraphic succession of coal measures which rides on major thrust surf aces is all of high-volatile bituminous rank, but despite the structural discordance no break in rank is discernible across these structures. The thrust faults therefore predate much of the coalification.Three major valleys expose cross sections of the folded coal measures and in each an increase invitrinite reflectance is demonstrable as individual seams are traced from ridge crest to valley floor. Thus, in these sections, a significant amount of coalification post-dates folding. The proportion of this post-folding coalification is found to increase toward the south of the coalfield.A late gravity-fault, exposed along the east crop of the coalfield, places high-volatile coal-bearing successions in contact with low-volatile coal and demonstrably is a reactivated thrust fault. Coalification at this locality occurred between these two different ages of faulting.The variations in rank and the subtleties of the coalification pattern have, together with systematic changes in the maceral composition of coal seams, had a profound effect on coal quality in the coalfield. Coking coals with a variety of properties occur together with some coals that have no caking capacity."

Jan 1, 1985

By D. Marotte, M. David

"A new exploration procedure is proposed for volcanogenic massive sulphide deposits of the Abitibi belt. ""Samples"" of acidic volcanic rocks (Si02 > 60%) were compiled from the literature. From the 574 samples collected, 322 were used in each of a number of experiments. Forward inclusion linear discriminant analysis performed on the untransformed geochemical data shows a general depletion in Na20 and CaO along with an enrichment in MgO for a ""proximal"" group of samples relative to a ""distal"" one. The percentage of misclassified samples reaches 20% to 30%, but test sets shows good stability.The exploration procedure was applied to the Normetal deposit, where the authors took 160 samples during the summer of 1977. It quickly leads to the definition of targets for more detailed exploration together with a good recognition of the old known deposit.IntroductionVolcanogenic massive sulphide deposits in the Abitibi belt (Quebec) are mainly found in rhyolites or acidic pyroclastics in the uppermost portion of a calc-alkaline volcanic series (Descarreaux, 1972). The deposits are thought to have formed syngenetically by the action of volcanic hydrothermal exhalations during the waning episode of a felsic volcanic cycle (De Rosen Spence, 1976). Alteration pipes of disseminated sulphides are commonly present. Metal deposition from hot springs, initiating convection cells in a submarine environment, may have been the dominant process in ore formation (De Rosen Spence, 1976)."

Jan 1, 1981

By P. R. A. Andrews

"A sample of flotation feed from Bakertalc Inc., High water, Quebec was subjected to flotation evaluation to improve the recovery of talc. A number of alternative frother/collectors and depressants as well as flotation parameters including pH, conditioning time, frother/collector concentration and pulp density were assessed. In addition, the possibility of using a size coarser than that currently employed for flotation (95% minus 50 um) was investigated.As far as possible, a laboratory duplication of the present circuit arrangement was folio wed so as to minimize the cost of any changes. The best results obtained were a concentrate analyzing 95.96% acid insol for a recovery of 65.98% after four stages of cleaning. With recirculation of cleaner tailings, the recovery would be higher.The possibility of using an alternative method, based on the natural ability of talc to float unaided by a frother/collector, was briefly explored with encouraging results.IntroductionBakertalc lnc ., located in the eastern townships at Highwater, Quebec, Is approximately 140 km east of Montreal near the Vermont, U.S. border. Originally called Baker Mining and Milling Co. Ltd., it has produced pulverized talc products since 1938(1 ), although records show that talc was mined in the area as early as 1871(2). Feed to the mill originally was obtained from local deposits, but since 1952 the van Reet mine near south Bolton, approximately 25 km from Highwater, has been the source of ore .In 1957 a Raymond high -side roller mill was installed which enabled production of a greater range of talc products and, in 1960, new crushing equipment and a dryer were added. Other additions to the mill were the introduction of wet magnetic separation, although this was later discontinued, and flotation to produce high-grade talc concentrates."

Jan 1, 1985

By Godfrey W. McDonald, Dennis E. Fredrickson

"Commercial coal mining has been recorded in Nova Scotia since 1863 and during this period an estimated 60,000,000 short tons of mine discard containing 10 1030% coal has been accumulated, Approximately 70% of these dumps are in the Cape Breton region and most are owned by the Cape Breton Development Corporation (CBDC), formerly DEVCO.The explosion of oil produced energy costs which created an increase in thermal coal demand as well as the desire to rehabilitate abandoned mine dumps encouraged coal reclamation. CBDC was receptive to a proposal from the Selminco Joint Venture and encouraged the building of the Princess Recovery Plant (1980) and The Summit Plant (1982).The mine dump contains scrap, waste rocks, coal and substantial quantities of fine shale. The scrap and oversize are removed and the remaining material slurried with water to a density of 1.45. The slurry is cycloned to separate the saleable thermal coal from the rejects which are returned to designated areas of the dump for contouring and revegetation.BackgroundThe recorded coal production in Nova Scotia from 1863 to 1980 was 390,000,000 short tons. This extraction was associated with an estimated 60,000,000 short tons of discarded material. This mining discard and coal washing plant reject are located in numerous, varying sized dumps throughout the mining areas. Approximately 70% of these dumps are in the Sydney coal field region of Nova Scotia. The coal content of these dumps varies from 10 to 30% coal with an average of 18%.Energy CostsThe explosion o f energy costs in the mid-1970s greatly increased the sale price of thermal coal which made recovery of coal from some of the dumps economical. The environmental benefit of these operations will be the rehabilitation of the dumps upon cessation of the coal reclamation operation."

Jan 1, 1983

By E. G. Parker

"Sherritt's zinc pressure leaching process converts zinc sulphide concentrates directly to zinc sulphate solutions and elemental sulphur. Thus, one pressure process step replaces both the roasting and leaching operations of the conventional roast-leach route. In addition, high single-pass extractions eliminate the need for residue treatments to recover unleached zinc. Because pressure leaching produces elemental sulphur, rather than sulphur dioxide, acid plants and smoke stacks are not required, and air pollution control and work-place hygiene are greatly improved. .In 1977, Cominco Ltd. and Sherritt Gordon Mines Limited jointly operated a three-tonne-per-day pilot plant to demonstrate pressure oxidative leaching of Sullivan zinc concentrate and the subsequent separation of elemental sulphur. The process consisted of regrinding the concentrate, continuous leaching at 150°C at elevated oxygen pressures in a four compartment autoclave and the subsequent recovery of elemental sulphur, either in the molten liquid form from a decantation autoclave or as a flotation concentrate. Of the zinc contained in the concentrate, 97% was extracted in 90 minutes, and 96% of the sulphur was converted to the elemental form.Following the successful pilot campaign, Cominco began building the world's first commercial zinc pressure leaching plant. This plant, which was in operation by late 1980, will eventually treat about 25% of Cominco's planned zinc capacity of270,000 tonnes per year.This paper describes the general process principles, the results obtained from the pilot plant and the integration of the process into Cominco's operations at Trail. The application of pressure leaching to a ""grass-roots"" plant is also discussed, and compared with conventional roast-leaching."

Jan 1, 1981

By Robert B. Parsons

"It is easy to throw darts at government - and government often deserves to be a target. This month, Tax Notes examines tax legislation from a different angle, and sees some bright spots.The following article is based on a paper presented by the author at the International Gold Symposium in Rio de Janeiro in August 1989Introduction""No man's life, liberty, or property are safe while the Legislature is in session.”With one federal government, ten provincial governments, and two territorial governments all claiming to have constitutional rights to tax and otherwise regulate Canada's mining industry, and with each of these thirteen governments pursuing their respective rights with some vigor, government involvement in one way or another is an accepted way of life in the industry. While one's initial reaction to government involvement in an industry might be one of scepticism or fear, generally speaking the federal, provincial, and territorial governments in Canada tend to be pro-mining. They recognize the importance of the mining industry to Canada, especially in terms of job creation and exports. It is not surprising, then, to find that an array of valuable fiscal incentives are available to the industry through federal and provincial legislation.This paper summarizes the principal incentives that are inherent in Canada's tax legislation, as well as the Canadian Exploration Incentive Program. Although it is beyond the scope of this paper to deal with all of the incentives that are available, it is noted that various forms of federal or provincial assistance are also available outside of specific legislation, through negotiation with government departments. This latter type of assistance is generally directed toward helping with the cost of infrastructure such as roads or hydro lines, or Jess often toward loan guarantees or similar financing assistance."

Jan 1, 1990

By Minoru Fujita, Ian M. Johnson

"A helicopter-borne geophysical survey was flown in 1978 over selected areas on Kyushu Island, Japan. The principal sensors were a moving source electro-magnetic system and a magnetometer. Maps of apparent resistivity were generated from the EM data. Based on the resistivity signature of known deposits within the survey areas, targets were selected for ground follow-up. Drilling of one such target in late 1980 resulted in the discovery of a gold deposit from which full production will begin in the summer of 1985. The deposit contains a minimum 120 tonnes (3.86 million ounces) of recoverable gold and is the largest in Japanese history. The deposit is in a geological setting previously unsuspected of hosting precious metal deposits. The case history suggests a preferred exploration strategy which might be employed in other similar geological environments.IntroductionThe Hishikari area is located some forty-five kilometres north of Kagoshima city, Kagoshima Prefecture, Kyushu Island, Japan (Fig. I). The area and its environs is one with a number of gold deposits which have been worked with varying results since the late 1800s. The large st deposit in terms of recovered gold is the Ohkuchi (or Oguchi) Mine (Fig . 2) which was recently closed due to exhaustion of reserves. The Ohkuchi Mine started production in 1896. A total of 22.2 tonnes (714 ,000 ounces) of gold, with an average ore grade of 13.6 grams/tonne (0.39 ounces/ton), was extracted over the Life of the mine.In an attempt to discover new deposits , the Metal Mining Agency of Japan (MMAJ) carried out a regional geologic mapping program of the area between 1975 and 1977. This was followed by a helicopter-borne electromagnetic and magnetic survey. The airborne survey was flown by Scintrex and the compiled results presented to MMAJ in early 1979."

Jan 1, 1985

By Audrey Wagenaar

Introduction ?? Rising public pressures are being placed on companies worldwide to protect the environment and the health and safety of their workers and local communities. ?? International bodies and shareholders want to make sure developments and companies can meet internationally acceptable standards for EHS. In 2005, Golder Associates was asked by the IFC to conduct a comprehensive review and update for their Environmental Health & Safety Guidelines including the mining sector.

May 1, 2008