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By R. R. Potter

"IntroductionAlthough iron formations were recognized in western New Brunswick about 1820, commercial production was not achieved until 1848. The Jacksonville deposits near Wood stock were developed first, and ore was treated at a blast furnace constructed 5 km to the southeast on the Saint John River. Several charcoal burners were also constructed. Pig iron was produced sporadically until 1884, when operations were finally suspended. There was little further interest in the area until 1953, when Stratmat Ltd. initiated an ambitious exploration program. At the same time, the company carried out research on an electric-reduction process to produce metallic iron and ferromanganese. The technical feasibility of this process (Udy process) was confirmed, however the high energy costs were prohibitive and work ceased in 1957. Some metallurgical research was carried out by Mandate Refining Ltd. about 1970 and more recently by the New Brunswick Research and Productivity Council.The Years Prior to 1848New Brunswick became a separate province in 1784, shortly after the influx of a large number of Loyalists from the United States. Man y of these people sett led along the Saint John River, including the area of excellent farmland near the present town of Woodstock.There were indication s that some of these earl y settlers recognized iron formations in the vicinity of Woodstock about 1820, however the nature of the deposits was not known until 836 when Dr. C.T. Jackson, a geologist commissioned by the Stat e of Maine, investigated the mineral potential of the area. Jackson (1836) described the ""ore"" as compact red hematite yielding 44 per cent pure metallic iron, and suggested that sizable tonnages may be present. It was about this time that an extensive limonite deposit was found in north-central Maine, near Mt. Katahdin. Other iron deposits were found in the Nictaux area of Nova Scotia, and a few years later at Londonderry."

Jan 1, 1983

By P. MacPhail, G. S. Dobby, I. M. Flint

"The objective of the laboratory work described in this paper has been to develop a method f or producing small gas bubbles at moderate to high gas rates in a flotation column. Small bubbles are particularly important for attaining reasonable flotation rates of fine particles. An ultrasonic aerosol generator has been employed to add frother solution directly to the gas stream. Using porous glass and filter cloth spargers, aerosol frother addition has produced bubbles at 1/2 to 2/3 the diameter of those produced by conventional frother addition to the liquid, at a lower frother consumption.IntroductionGas bubbles are generated in a flotation column most commonly by forcing gas through a porous medium called a sparger. Typical sparger material includes rubber (pierced with small holes) , fabric (such as filter cloth), fritted glass, or porous metal (steel or bronze) . Solid sparger material is suitable for laboratory use; however, for industrial applications a flexible sparger such as rubber or fabric is necessary to prevent the eventual plugging of orfices with solid particles and/ or precipitates. An exception to this is the use of a gas liquid contactor external to the column in combination with pressure release of gas in water, a method that has been demonstrated to produce very small gas bubbles. The typical objective of bubble generation for flotation column purposes is to produce bubbles with diameter of about 0.1 cm (and less) at a gas superficial velocity of 1 cm/s to 3 cm/s. In general, the smaller the bubble, the better. In man y cases, though, there is little , or nothing, gained by generating bubbles less than about 0.05 ern in diameter.Several factors affect bubble size when generated by a sparger: gas rate, orifice diameter, sparger surface area, surfactant type, surfactant dosage, and static head. At very low gas rates bubble diameter is independent of flow rate and is proportional to orifice diameter. At the moderate gas rates encountered in flotation columns bubble diameter, db' is related to gas flow by: db oc vg n, where vg is superficial gas velocity (rate of gas flow per unit column area). For porous steel and filter cloth, n has a value of about 0.25 for vg between 0.2 cm/s and 2 cm/s(2). The magnitude of the effect of orifice diameter at these gas rates is unclear. The effects of frother type and concentration on bubble size issuing from a single orifice have been measur ed by Miagkovaru , shown here in Figure I(IS). The reduction in bubble diameter upon surfactant addition is due to the lowering of interfacial tension created by adsorption of surfactant at the gas liquid interface."

Jan 1, 1988

By R. S. James, S. P. Goff, A. E. Armitage

"Abstract - Oxide-facies banded iron formation in the Third Portage Lake area is hosted by ultramafic and calc-alkaline volcanic rocks and related sedimentary rocks of the Archean (2.8 Ga) Woodburn Lake Group, 80 km north of Baker Lake. These rocks record at least two phases of metamorphism/ metasomatism. Greenschist facies metamorphism, in the temperature range of 370°C to 520°C and at pressures above 2.3 kbar, has affected all rocks on a regional scale. Later mineralization and alteration of banded iron formation (BIF) and associated volcanic rocks resulted from metasomatic fluids which carried Mg, K, Ca, S, As, Cu and Au. These fluids were confined to ductile to brittle, cross-cutting and layer-parallel micro-shears developed in the thickened hinge region of a shallow plunging recumbent fold. Metasomatic reactions yielded cummingtonite + biotite-bearing assemblages which are associated with strongly mineralized iron formation. Pyrrhotite is the dominant sulfide phase and occurs within ductily deformed iron formation where it pervasively replaces magnetite. Minor fine-grained chalcopyrite and arsenopyrite generally occur as inclusions within pyrrhotite and recrystallized magnetite, and rarely as individual grains. Pyrite is restricted to brittlely deformed iron formation, and to the contact between iron formation and altered ultramafic rocks, where it is associated with quartz veins. Pyrite typically replaces pyrrhotite. Native gold is associated with both pyrrhotite and pyrite, but higher gold concentrations are associated with pyrite. Grunerite/Ca-amphibole + stilpnomelane and sparse pyrrhotite and pyrite characterize weakly mineralized iron formation. Within adjacent ultramafic rocks, metasomatic reactions yielded assemblages of interlayered Ca-amphibole + biotite, and talc + Ca-amphibole + carbonate + biotite. K-Ar geochronology on metasomatic biotite from mineralized BIF yielded a 1791 ± 32 Ma age.An epigenetic model is favored for the emplacement of gold. The age of the gold mineralization in the Third Portage Lake area is uncertain, but may be Proterozoic based on the preliminary isotopic age and by analogy with Proterozoic gold deposits elsewhere in this part of the Churchill Structural Province."

Jan 1, 1996

By R. del Villar, A. R. Laplante

"This article presents four grinding simulation programs, written in Applesoft BASIC. The firs t two calculate residence time distributions (RT Ds) for open and closed loops mills. The third program calculates the select ion functions from the RTD, breakage function and particle size distribution (PSD) o f the feed and discharge. Two linear regression programs are also included to calculate the breakage function. These results are used in the fourth program to simulate continuous or batch grinding kinetics.The modelling approach presented is the size discrete, time continuous matrix formulation presented by Reid (1965) from concepts originally proposed by Epstein (1948). It is at the present time the most widely accepted phenomenological model of grinding kinetics and is standard textbook material (Austin et 01., 1982; Kelly and Spottiswood, 1982, p. 152). The concepts of RTDs and tracer testing originated from chemical engineering theory and practice, and are well presented in Leven spiel (2n d Ed . 1972 , Ch. 9) .Applesoft* was chosen because it is compatible with many micro computers. It is also one of the simplest and least powerful BASIC versions. Thus it can easily be adapted to other more complex BASIC versions.Open Loop Residence Time Distributions (Program RTDOPEN)As mixing, channelling, stagnation and short-circuiting all affect slurry motion in tumbling mills, transport characteristics are very complex an d cannot be derived from fundamental principles. Fortunately , as grinding follows first order kinetics, transport characteristics for the purpose of grinding simulation ca n be represented by the RTD of the slurry phase . It is normally determined using liquid tracers, as it has been demonstrated and is commonly accepted that in industrial ball mill s, the RTD of the so lid phase is particle size independent and equal to that of the liquid phase."

Jan 1, 1985

By Fernand Dubuc

"The New Pascalis property is situated in Louvicourt and Pascalis townships, about 200 km east of Val d'Or, Quebec. It is made up of 38 claims under option to SOQUEM since August I, 1981 during which time SOQUEM has earned a 60% interest. The property is underlain by archean basaltic volcanics that have been intruded along the west boundary by the Bourlamaque batholith, and by north -trending dykes.The 1982 disco very is related to the re-evaluation of a 1931-gold showing located in the southeastern part of the property, a combination of the presence of a weak IP anomaly at the eastern end of the showing and overburden stripping at that location, resulted in the discovery of a mineralized diorite dyke.The dyke, which strikes N 20 ° Wand dips vertically , has intruded E-W striking agglomerates. The dyke contains south dipping, gold-hearing quart z-tourmaline-pyrite veins that are distributed in a ladder-type arrangement. Visible gold may he observed in drill core, and is generally associated with pyrite porphyroblasts.Diamond drilling has outlined th e dyke for a strike length of 300 11/ and a width of about 10 m, Result s of this drilling indicate, to a depth of 155 m, reserves of 834 000 metric tonnes grading 8.25 g Au/t un cut or 5.38 g Au/t cut to on e ounce. However, four deeper holes have added depth extension to 400m. Also, west of the dyke and within 150 m, other promising gold values have been intersected within quartz-tourmaline veins associated with other parallel dykes."

Jan 1, 1985

By Bruce J. Barker

"Environmental concerns have recently been growing over the disposal of reactive desulphurizing slag. Consequently, increased pressure has been placed on the foundry industry to reduce the reactivity of this slag.To address this problem, Cyanamid has developed a new product which significantly reduces the calcium carbide content of the desulphurizing slag. Testing equipment and procedures have also been developed to evaluate both the existing levels of carbide in the slag and the decreased levels which are achieved with this new material.The development and use of this engineered carbide desulphurizer has made possible significant environmental and efficiency improvements in the field of calcium carbide desulphurizing. Consequently, the lifespan of calcium carbide in ductile iron desulphurization has been increased, as have the benefits of its use in the foundry industry. IntroductionIn the production of ductile iron, calcium carbide has long been used for hot metal desulphurization external to the cupola. Its cost effectiveness, reliability and ease of use have traditionally made it the desulphurizer of choice for a great majority of ductile operations. Recently however, environmental concerns have been raised regarding the quantity of calcium carbide remaining in the slag after desulphurizing. Analysis has shown that as much as 25070 of the weight of the slag may contain active carbide. This has caused disposal concerns as calcium carbide when in contact with water, produces acetylene via the following reactionr:"

Jan 1, 1992

By Kevin Ross

Feasibility Study Team Processing / Engineering?Hatch, Vancouver Mining / Reserves?Australian Mine Consultants, Brisbane Geology / Resources?Roscoe Postle Associates, Vancouver Environmental / Permitting?Rescan, Vancouver Tailings BGC, Kamloops Probable Mine Components Mining tending towards caving methods Underground mine accessed by shaft /conveyor & decline Processing plant producing copper concentrate containing gold Concentrate trucked to rail head for export Non saturated tailings disposal

May 1, 2006

By R. S. James, S. P. Goff, A. E. Armitage

"Oxide-facies banded iron formation in the Third Portage Lake area is hosted by ultramafic and calc-alkaline volcanic rocks and related sedimentary rocks of the Archean (2.8 Ga) Woodburn Lake Group, 80 km north of Baker Lake. These rocks record at least two phases of metamorphism/ metasomatism. Greenschist facies metamorphism, in the temperature range of 370°C to 520°C and at pressures above 2.3 kbar, has affected all rocks on a regional scale. Later mineralization and alteration of banded iron formation (BIF) and associated volcanic rocks resulted from metasomatic fluids which carried Mg, K, Ca, S, As, Cu and Au. These fluids were confined to ductile to brittle, cross-cutting and layer-parallel micro-shears developed in the thickened hinge region of a shallow plunging recumbent fold. Metasomatic reactions yielded cummingtonite + biotite-bearing assemblages which are associated with strongly mineralized iron formation. Pyrrhotite is the dominant sulfide phase and occurs within ductily deformed iron formation where it pervasively replaces magnetite. Minor fine-grained chalcopyrite and arsenopyrite generally occur as inclusions within pyrrhotite and recrystallized magnetite, and rarely as individual grains. Pyrite is restricted to brittlely deformed iron formation, and to the contact between iron formation and altered ultramafic rocks, where it is associated with quartz veins. Pyrite typically replaces pyrrhotite. Native gold is associated with both pyrrhotite and pyrite, but higher gold concentrations are associated with pyrite. Grunerite/Ca-amphibole + stilpnomelane and sparse pyrrhotite and pyrite characterize weakly mineralized iron formation. Within adjacent ultramafic rocks, metasomatic reactions yielded assemblages of interlayered Ca-amphibole + biotite, and talc + Ca-amphibole + carbonate + biotite. K-Ar geochronology on metasomatic biotite from mineralized BIF yielded a 1791 ± 32 Ma age.An epigenetic model is favored for the emplacement of gold. The age of the gold mineralization in the Third Portage Lake area is uncertain, but may be Proterozoic based on the preliminary isotopic age and by analogy with Proterozoic gold deposits elsewhere in this part of the Churchill Structural Province. Copyright"

Jan 1, 1996

By M. Isac, R. I. L. Guthrie, S. Ge

The Al-Mg-Sc-Zr alloys have shown exceptional potential as structural materials for transportation applications. These alloys have proved to be good candidates to be processed as thin strips via the Horizontal Single Belt Casting (HSBC) process. The HSBC process is a near-net-shape casting technology, which involves casting molten metal directly into thin strips, close to the final product thickness, at high cooling rates. It offers an efficient, economical and environmentally-friendly approach to the production of metal strips. Fluid mechanics and associated heat transfer are important aspects of any casting process, and the novel HSBC process is no exception. Three dimensional Computational Fluid Dynamics (CFD) simulations using ANSYS FLUENT 14.5 were performed, in order to assess the importance and effects of the various operational conditions of the HSBC process. This enabled process parameter optimization. Numerical predictions were validated against experimental casting results.

Jan 1, 2014

By E. Yalçin, A. Ünal

In transitional mineralization, the sill of the underlying variogram is relatively easily estimated, but the estimation of the nugget effect may be more difficult. This study aims to determine for massive copper deposits just how sensitive the estimations of ore reserve, economic copper content, total net value, and ultimate pit limits are to the errors of estimation in the nugget effect of the spherical variogram model. A massive copper deposit which has a log-normal distribution and a spherical variogram was simulated on a rectangular grid using the turning bands method. By using the three dimensional random kriging method, the mean block grades were estimated at four different sampling densities. The ultimate pit-limits were determined by using the two-dimensional dynamic programming algorithm. To calculate the estimation errors, the values obtained by using the actual nugget effect and structured component values were deducted from the estimations obtained using the incorrect nugget effect and structured component values. For isotropic massive copper deposits, it was found that the ratio of the nugget effect to the structured component of the spherical variogram has no significant effect on either the block grades estimated by the kriging method or on the ultimate pit limits.

Jan 1, 1992

By E. I. Vargha-Butler

The determination of surface tensions and contact angles of coal particles is of great interest for coal beneficiation processes such as froth flotation and oil agglomeration and for the inclusion of coal particles into oil droplets as a means of enriching the fuel. Methods for contact-angle measurements on small irregularly shaped solid particles have not been available in the past. Therefore, we recently developed a novel technique to determine contact angles and surf ace tensions of coal particles. Two types of bituminous and one type of subbituminous coal particles have been tested. The technique used is called the freezing-front technique and it considers the behaviour of the test particles (in the range of 20-250 pm) at the solidification front of carefully selected, well-defined solidifying melts (matrix materials) such as thymol, biphenyl, naphthalene, salol and 2-phenyl phenol.The results show that the technique works well, providing quantitative and detailed information on the wettability of coal particles. The sensitivity of the method is so high that a difference in contact angle of approximately 4 degrees between the smaller and the larger particles is clearly registered.

Dec 1, 1981

By George R. White

"The Phalen Colliery, the Cape Breton Development Corporation's flagship, is now producing thermal and metallurgical grade coal in Eastern Canada's Sydney Coal Field. The colliery is a drift mine operating under the waters of the Atlantic Ocean. Improved mechanization, including a 2200 tonne per hour cable conveyor, and the introduction of modern retreat longwall mining methods as part of the Phalen concept are now paying off in better productivity and low operating costs. Geological conditions within the coal field are consistent with plans for ever greater outputs in the 1990s. Although much of the current production improvement is related to uprated machine capacity and simplified mines planning there is potential for even further development in the areas of maintenance, process control and engineering. Human resource development will also be a key factor. These programs are now well under way and Phalen Colliery is poised for top results in the 1990s. Comparison of the CBDC's top producer with similar operations elsewhere in the world, quantifies that potential.IntroductionAn exciting new mining project which has recently started production on Canada's East Coast has been conceived and designed to be one of the most modern and productive coal mining operations in North America.As with all mining operations, the business is basically that of material transportation. Daily, the product is transported many kilometres from the underground face to the surface and then to washing facilities. Men, materials and equipment are transported to and from the surface and the operating faces and services, such as electrical power, ventilating air, fresh water, discharge water, communications and compressed air are supplied throughout the operation to cover operating requirements. On all accounts the operation has been designed to take advantage of the latest proven technology."

Jan 1, 1990

By Robert B. Parsons

"This month, Tax Notes focuses on two features which can potentially ""dress up"" a new issue of common shares to make the shares more attractive to investors. Attaching warrants to a share issue is a relatively common practice, and recent years have seen an imaginative variety of different kinds of warrants, some of which can be subject to somewhat different tax treatment . A less common financing strategy which certainly deserves some consideration involves the possibility of utilizing ""Share Purchase Tax Credits "" in conjunction with a new share issue.IntroductionPrevious subjects covered in Tax Notes have dealt with flow-through shares and other tax angles which can make equity issues more appealing to potential investor s. Two other techniques which can add zest to a new stock issue involve the utilization of warrants and ""share purchase tax credits"" (or SPTCs). This article takes a brief look at the better known subject of warrants and the lesser known matter of SPTCs.Of course, this paper presents only a relatively general summary of the income tax implications of warrants and SPTCs, and is not intended to be a definitive commentary on all of the detailed and complex tax issues that might be relevant in the circumstances."

Jan 1, 1985

By R. Pakalnis, H. Miller, Madill. T.

"This paper describes a methodical approach to the estimation of the orientation and the magnitude of in-situ stresses. The study was performed at the Ruttan Mine, Sherritt Gordon Mines Ltd. , a 6,000 T.P.D. underground operation, located in northern Manitoba, Canada. It involves an initial estimate to be made based upon: structural interpretation • virgin stress measurements conducted in other areas (world wide, regional)The verification of the prevailing stress regime was made by conducting CSIRO hollow inclusion(1) overcoring measurements. The current cost for a virgin stress determination is about $7000 per measurement(2) and the difficulty encountered in attaining a good reading is high. This paper will describe the analytical procedures employed at Ruttan in evaluating the in-situ stress magnitude and orientation based on three overcore tests. It is proposed to perform an additional six measurements in order to verify the following results:Vertical stress = av (MPa) = 0.027 by depth (m)Major principal stress = o! """" 2.5 xav (340°/-20°)*Intermediate principal stress = a2 - 1.2xav (070°/0°)Minor principal stress = a3 """" o.8xov (160°/-70°)IntroductionThe Ruttan Mine of Sherritt Gordon Mines Ltd., a 6,000 T.P.D. underground operation, is located in northern Manitoba, Canada (Fig. I). The Ruttan copper-zinc orebody is a multi-lensed, steeply dipping (70 degrees) en-echelon deposit. Individual lenses have a maximum strike length of 350 m with widths varying from 7 m to 61 m. The mining method is o pen stoping with delayed backfilling and extends from surface to 860 m below surface."

Jan 1, 1985

By G. Grant Smith

In situ bulk density of coal is a variable applied to various aspects of coal resource evaluation, such as compositing ply analyses of coal attributes that are expressed on a weight per cent basis, and determining tonnages from volume estimates. Its value is a function of composition and porosity of the in situ material. When densities of ash-free coal, ash and water are fixed, in situ bulk density of a coaly mix can be expressed as a function of proportionate weight of ash in the mix. Correlations between in situ bulk densities and weight per cent ash contents of coaly mixes have been estimated for four general rank classes of coal (low medium volatile bituminous, high volatile bituminous, subbituminous, and lignitic).

Jan 1, 1991

By Ronald E. Pike

"PREFACEAt the CIM Annual General Meeting in Quebec City, R.E. Pike of The Toronto-Dominion Bank described how the Canadian banking industry worked with the minerals industry to assemble the large capital requirements for resource projects in Canada and overseas. He developed a profile of the mining industry and Canadian banking, both being important sectors of the Canadian economy and global in context. He also outlined the banking and financing partnership that existed in the past. In looking to the future and challenge that lies ahead f or each industry, Mr. Pike questioned whether the financing practices of the 1970s will be acceptable over the next decade. In that regard, he highlighted the risks that impact on each industry and illustrated how that financing partnership might evolve in response to those forces. The folio wing is a synopsis of his paper.IntroductionThe Canadian mining and metals industry is prominent in the domestic economy and respected internationally. Any measure of its performance illustrates that status-percentage of GNP, employment, exports, capital investment, size relative to other producing nations, etc.Energy, Mines and Resources Canada has forecast that the non-fuel minerals industry will grow in real terms by an average annual rate of 3.0% over the period 1981 to 1991. Using the GNP as reference, that growth in non-fuel mineral production will represent 7.7% of GNP. In translating that growth to capital expenditure, the EMR Canada estimates the aggregate amount at $43.8 billion ('79 dollars) or approximately 12% of total business investment in Canada during the 10-year period.About half of the $43.8 billion will be devoted to the ferrous sector-$8.4 billion in iron ore mining and $12.4 billion in the steel industry. Capital investment in nonferrous s projects is estimated at $13.3 billion, and it is projected at $6.7 billion for industrial minerals. The residual $3.0 .billion is exploration spending."

Jan 1, 1982

By John H. Fowler

"Barytes is one of the major components of drilling fluids used in oil and gas well-drilling. This mineral's close association with the petroleum industry bestows it with a commodity status not enjoyed by many other industrial minerals. Approximately 85% of world barytes production is used as a weighting agent in oil and gas well drilling while the remaining 15% is consumed mainly in the manufacture of barium chemicals, glass and as a pigment, filler or extender.Barytes mining began in Nova Scotia around 1865 and has continued until the present. Currently there are three barytes producers in the province one exporting pharmaceutical-grade barium sulphate and the other two supplying drilling mud-grade barytes to the offshore. Several barytes exploration and development programs are underway with excellent possibilities that Nova Scotia deposits will supply a significantly larger share of the drilling mud-grade barytes used in east coast drilling programs.Currently there is renewed interest in barytes activities in Nova Scotia because of its use as a weighting agent in drilling flu ids used in offshore oil and gas drilling programs.This paper reviews the use of barytes by the well drilling industry; outlines the history of barytes mining in the province, progressing to present-day exploration, development and production activities underway in Nova Scotia; and concludes with the market potential for Nova Scotia barytes."

Jan 1, 1986

By G. W. Davies

"IntroductionThe development of British Columbia's northeast coal deposits, represents the single biggest industrial undertaking in British Columbia's history.As a result of this development, several thousand jobs were created, hundreds of millions of dollars in new tax revenue and billions of dollars in new foreign exchange began flowing into Canada.The Northeast Coal Development began in 1981 with the signing of sales contracts to ship a total of 6.5 million tonnes of metallurgical and additional quantities of thermal coal annually to Japan over a 15-year period. The current long-term agreements contain provisions for extension to 20 years.The sales contracts with a group of Japanese steel mills were signed by two Vancouver-based mining companies, Quintette Coal Limited and Teck Corporation. The agreements followed years of exploration and negotiation beginning in 1968.The first shipment of coal from Quintette and Teck's Bullrnoose Mine was transported by BC Rail and Canadian National Railways to the Ridley Island coal port in the fall of 1983."

Jan 1, 1992

By Robert B. Parsons

"The Canadian Exploration Incentive Program (CEIP), which was announced by the federal government on May 3, 1988, promises to maintain the viability of flow-through shares as a financing mechanism which has proven to be so crucial to the health of the junior exploration sector. This month, Tax Notes examines, the main features of CEIP, which will come into play on January J, 1989. IntroductionOn May 3,1988, the Honourable Marcel Masse, Minister of Energy Mines & Resources, and the Honourable Gerald Merrithew, Minister of State (Forestry and Mines) announced the Canadian Exploration Incentive Program (CEIP). Under CEIP, the federal government will make cash payments to eligible applicants equal to 30% of eligible exploration expenses. CEIP payments will be available with respect to both mineral, and oil and gas, exploration. In essence, the program will replace the ""mining exploration depletion allowance"" (MEDA) presently applicable to mineral exploration, and the Canadian Exploration and Development Incentive Program (CEDIP) which is presently available to the oil and gas exploration sector.This paper discusses briefly the main features of CEIP insofar as the program will affect mineral exploration. The comments herein are based on the Canadian Exploration Incentive Program Act which received Royal Assent on July 21, 1988, and on a discussion paper which was released by EM&R in May 1988. The bulk of the rules relating to the program will be in the form of regulations which have yet to be finalized. It is understood that EM&R would like to have the regulations in force by October I, 1988, when the oil and gas portion of CEIP becomes effective. (The rules relating to mineral exploration will become effective January I, 1989)."

Jan 1, 1988

By William Petruk

Mineralogical investigations in connection with gold metallurgy are usually performed to find the reason for poor recoveries by cyanidation or by other leaching techniques. Poor recoveries most commonly are obtained when (I) native gold is encapsulated in an insoluble mineral as "invisible gold"; (2) native gold is coated with a precipitate; (3) gold-bearing products are insoluble in cyanide solutions; (4) carbonaceous material in the ore adsorbs gold; and (5) associated minerals decompose and consume cyanide. Samples of refractory material quite often have low gold tenors. It is difficult to find the gold-bearing minerals in such samples with an optical microscope because the probability of finding trace minerals in samples is small. The probability decreases with decreasing grain size of the gold-bearing mineral and with decreas¬ing gold tenor of the sample. Techniques have been developed to increase the success rate of finding gold grains; some are (1) concentrating heavy minerals; (2) preparing special polished sections; (3) searching with an image analyzer; and (4) dissolving associate silicate and sulphide minerals.

Jan 1, 1989