Search Documents

By W. T. Irvine

"The H.B. Mine, a zinc-lead operation of the Consolidated Mining and Smelting Company of Canada Limited (Cominco), is in south central British Columbia, on Sheep Creek, a west-flowing branch of the Salmon River. It is 3 miles by road from B.C. highway No. 6, 30 miles south of Nelson, B.C., with an excellent highway connection to the smelter city of Trail, 35 miles from the mine. The nearest permanent settlement is the village of Salmo, 7 miles distant by road. The mine is situated along a belt containing other important zinc-lead deposits, including those of the Canadian Exploration Company, 3 miles to the south, and the Reeves MacDonald mine, 9 miles distant again to the southwest.Deeply oxidized outcrops were located in 1907 on the north side of Sheep Creek valley by two prospectors named Horton and Benson. The property was given the name H.B., after the two discoverers, and there commenced a long and intermittent series of mining operations designed mainly to develop and extract oxidized lead-zinc ore. In 1925 a determined attempt was made by a British syndicate to develop a large tonnage of sulphide ore, but this ended in failure after some 3,000 feet of lateral development had been done. In 1927 Cominco acquired the mine, but it lay idle until 1946 when a geological study was followed by a program of surface drilling which encountered extensive sulphide mineralization. An underground development program revealed more details of the deposit, and sufficient ore was found to warrant construction of a 1,000-ton mill. Mine preparation and mill construction were completed by early 1953, but production was deferred due to low metal prices. The mine was finally brought into production early in 1955."

Jan 1, 1949

By H. J. Chalmers

THE H.B. MINE and concentrator are located in the Nelson Mining Division of British Columbia, on the north side of the Sheep Creek valley about seven miles southeast of the town of Salmo. It is an operation of The Consolidated Mining and Smelting Company of Canada, Limited (Cominco), which has its metallurgical plants at Trail, about 25 miles west. The property was originally staked about 1907 by Horton and Benson, whose names are commemorated in the designation "H. B." Up until 1927, a considerable amount of development work was done in the upper levels by various companies. Cominco purchased the ?property in 1927 and carried out intermittent work until 1946. Following this, an extensive surface diamond drilling programme and a subsequent underground exploration were undertaken. Sufficient ore was outlined 'to warrant the construction of a 1,000: ton concentrator. This was started in April, 1952, and completed by the spring of 1953. However, because of adverse base metal market conditions, operation was deferred until May, 1955.

Jan 1, 1957

By J. Hall Carpenter

"Wet concentration has, in the history of ore dressing, been the primary treatment method following crushing, grinding and sizing, when these have been necessary. The evolution of new methods of gravity concentration has been comparatively slow.Today, the most significant and sophisticated of the new types of gravity concentrators is, no doubt, the cone concentrator developed by Ernst Reichert of Mineral Deposits Pty. Limited in Southport, Australia. These units have now had some years of use in the field, are becoming one of the standard tools of the industry and their metallurgical results, as outlined in this paper, are out-standing."

Jan 1, 1966

By M. R. Babcock

"The Rabbit Lake story began in the late sixties and will continue well into the twenty-first century. It is a story of success, of multiple ore body discoveries, of unique systems, and new methods made possible through innovative and state-of-the-art design. Two quite different geological systems host the five ore bodies mined, or slated to be mined. These two systems have yielded two distinct ore types, each with characteristic mineralogical properties and each requiring its own specific mill circuit.Emphasis on communications and our unique systems have led to a satisfactory and fulfilling work environment resulting in the historically low employee turnover which has contributed to the operation success.A comprehensive environmental study after twelve years of operation has given the Rabbit Lake Operation a completely clean bill of health. INTRODUCTIONRabbit Lake can be described as Saskatchewan's first highgrade uranium mining operation, which set the stage for the province's current role as the leader in uranium mining throughout the western world. The importance of the Rabbit Lake operations - past, present and future.LocationThe Rabbit Lake operation is located in northeastern Saskatchewan (Fig. 1)- 805 km north of Saskatoon, Saskatchewan, and 814 km northeast of Edmonton, Alberta. OwnershipGulf Minerals Canada Limited discovered the Rabbit Lake deposit in 1968. Mining operations began in 1975and were operated by Gulf until purchased by Eldorado Nuclear Limited in 1982. In 1988, Eldorado merged with Saskatchewan Mining Development Corporation (SMDC) to form Cameco-A Canadian Mining &. Energy Corporation. The new corporation is one of the world 's largest uranium companies.Cameco's $1.5 billion in assets include the Rabbit Lake uranium mine (Cameco 100010); the Key Lake uranium mine (Cameco 66.67%; Uranerz Exploration and Mining Limited 33.33%); the Cluff Lake uranium mine (Cameco 20%; Amok Ltd. 80%); the Fuel Services Division at Blind River and Port Hope, Ontario (Cameco 100%); and a 100%); and a 48.75% interest in the Cigar Lake uranium deposit which is now at the test mining stage (Cogema Canada Ltd . 32.625% ; Idemitsu Uranium Exploration Canada Limited 12.875%; Corono Grande 3.75%; Korea Electric Power Corporation 2%). In addition, Cameco is involved in a number of base and precious metal explor ation projects."

Jan 1, 1989

By D. A. Sloan

"THE FIRST COMMENTATOR that I will call on is Mr. W. G. (Bill) Brissenden, Vice-President, Mines, Noranda Mines Ltd. Bill, would you care to comment.W. G. BRISSENDEN ...Mr. Chairman, Ladies and Gentlemen, I spent some time reading the four papers that were presented here, yesterday evening, and decided that the four to six minutes that I had been allotted for this afternoon were going to be pretty tough to meet. It's a very big subject and I just hope that I will be able to stay within my time limit. As has been so aptly demonstrated by the members of our panel here this afternoon young men in growing numbers continue to be attracted to careers in the mineral industry, especially to careers in mining engineering. Now from 80 the point of view that the profession may have regained its status this is indeed welcome news. However, perhaps all of the members seem to have the suspicion that the number of mining engineers that the industry can absorb is a much lower figure than previously forecast. It is said that technical school graduates are now occupying some of the jobs once considered the private preserve of the mining engineer and also that mining engineering undergraduates are having trouble locating summer employment. If these interpretations of mine are correct then we are now confronted not only with our old dilemma - whither the mining engineer - but also with an urgent need to solve it. We cannot allow our profession to become once again an undesirable one in the eyes of our youth because if we permit such a thing to happen a second time the profession may never recover."

Jan 1, 1972

By Chris Twigge-Molecey

Demand for metals will continue to grow as global population numbers and prosperity levels steadily increase. Consequently, there will continue to be a need to design and construct new metallurgical plants. Business success in general requires projects to be financially successful and return appropriate value to their owners. However, in the metals industry, private and public sector financing sources have become very sensitive to the perceived inability of projects to contain costs and meet other business objectives. Thus, the capital for projects has become more difficult and expensive to obtain. It is instructive to note that Ernst and Young (2011) identified that: “Delivery of predictable project results bestows competitive advantage and market confidence to those corporations who successfully instill this discipline”. The implication for future projects is that they must be systematically developed to minimize perceived risks—and more importantly—to demonstrate that the risks are managed to achieve the business case. Then, provided that the project has been developed in a well-structured way, project success can again be defined as a project with: a final cost within 10% of the budget approved at the end of FEL3, when the project is properly defined and the permit conditions are agreed upon; a start-up date within three months of the definitive, scheduled startup date; production levels at 85% of design capacity within a year of starting commercial operation; production meeting the target environmental restrictions; and with zero lost time accidents during construction and startup. The plant design is one of many integrated activities required to achieve these objectives. This book represents a valuable link between the existing engineering literature that encompasses a wide range of engineering fundamental textbooks and design manuals and the project management literature such as the Project Management Body of Knowledge, or PMBOK® (Project Management Institute, 2014). It is evident throughout this book, that the design team is a small but essential part of a much larger project team comprising the project management, construction management, and construction contractor staff. Design activities must be regarded and managed as part of the integrated whole, with two fundamental links throughout the design process:

Jan 1, 2015

By Lionel A. York

This paper outlines the type of water-bearing formations encountered in the Prairie Sediments and describes a method for effectively sealing these zones in order that shaft-sinking operations may be carried out with safety. Details are given of the procedure for carrying probe holes ahead of the shaft bottom. These probe or grout holes are employed for establishing a series of overlapping grout covers around the proposed shaft excavation to safeguard against large inflows of water during sinking. The pattern and length of grout covers cannot be standardized, and each cover needs to be specially designed to suit the varying ground conditions. In order to provide effective protection through the Prairie Sediments, the number of holes in any one cover would not be less than 8, and possibly as many as 64 would be required in certain zones. The length of covers would vary from 100 ft. to 250 ft. Emphasis is placed on the need for obtaining accurate geological and water information from exploratory holes, drilled in the shaft vicinity, in order to effectively plan all grout covers.

Jan 1, 1964

By A. H. Ransom, M. E. Robb

The Salmita Gold Mine is located 240 air kilometres northea t of Yellowknife on the east shore of Matthews Lake. Salmita is one of several gold showings which are regionally associated with the steep easterly dipping contact zone between mafic, intermediate and fe lsic volcanics to the west and overlying finely laminated argillaceous sediments to the east. The volcanic assemblage forms a narrow 2 m to 7 m wide north to northwesterly trend ing Belt of Yellowknife Supergroup Archaen greenstone rocks. The contact zone exhibits exhalite character and the increased sulphide content provides a di stinct VLF-EM , IP/Resisti vi ty and/or magnetic signature. Gold occurs at or near this contact in three main settings: associated with si liceous vein-like structures; with finely disseminated sulphides within ericitic altered upper fe lsic tuffaceous unit ; or with quartz in narrow shear zones within the overlying sediment . The B-Vein is of the former type with free mi ll ing gold occurring within a highly sil iceous zone having an average widtn of 1.69 m. Alteration is intense within the immediately su rrounding host lithologies and includes the development of si lica, carbonate, sulphide, sericite and chlorite with minor graphite, epidote. tourmaline and scheelite. The mineable zone above the 4th level (-200 m) ha an average strike of 160 m and is divided into three south plunging ore shoots separated by the regional Salmita Shear Zone in the south and by a low-grade structural hiatus in the north. Production from the B-Vein commenced in August 1983 based on a diluted in situ ore reserve of 140,000 t grading 26.6 git Au . As of December 31, 1985, a total of 131 ,537 t grading 27.8 git Au have been mined at a ra.te of 160 t per day and a 96.4 percent recovery, to produce 3,522 ,000 g (113,227 ounces) of gold . Current (January I, 1986) reserves total 45,500 t grading 37 g/t Au down to the 10th level (-500 m) .

Jan 1, 1986

By C. R. Edwards

"Equity Silver Mines Limited, Canada's largest silver mine, has designed, built and operated a leach plant to reduce the levels of antimony and arsenic in its silver-gold-copper flotation concentrate. The orebody contained deleterious antimony and arsenic minerals in such proportions that the economic long-term sales contracts necessary to obtain project financing could not be procured. Construction of the leach plant therefore allowed development of the mine to proceed. Although the plant took some time to reach design throughput and product specifications, due to the complex and unique nature of the operation, these goals were successfully met and surpassed. This paper describes the physical plant and/or process technology modifications made to mold the main processes-concentrate leaching and filtering, autoclaving and filtration of by-products, and crystallization of salt cake-into an effective, economic operation.IntroductionEquity Silver Mines Limited, a member of the Placer Development Group, owns and operates an open-pit silver mine and related facilities located 37 kilometres southeast of Houston in north-central British Columbia. The mine occupies a 44 I-hectare (1089 acre) site at an elevation of 1300 metres (4265 feet) on the Nechako Plateau. Producing a copper concentrate containing high values of silver and gold, it is the largest silver mine in Canada and one of the largest in the western world. Equity stresses open communications, positive motivation, and production with safety, and achieved the best mine safety record in western Canada in 1984."

Jan 1, 1985

By P. Garritsen, J .. A. Blanco, M. C. Bell

"By 1994, Inco Limited will lower sulphur dioxide emissions from the Copper Cliffsmelter by 60% to 265 000 tonnes/year, primarily through implementing two key process changes. First, new milling technology will permit economic rejection of additonal pyrrhotite prior to smelting. Second, a bulk coppernickel concentrate will be oxygen flash-smelted, thereby eliminating the existing multi-hearth roasters and reverberatory furnaces . All copper will be recovered in the matte separation plant as a nickeliferous chalcocite, and will be oxygen flash-smelted for blister production. This paper outlines the development of the project and describes the process, including the flash furnaces, new sulphuric acid plant and additional oxygen plant.IntroductionInco 's SO2 Abatement Program will lower sulphur dioxide emissions at Sudbury from the current levels of 685 000 tonnes per year to 265 000 tonnes per year by 1994 as required by Ontario' s countdown on acid rain regulations.It is the high tonnage of sulphur mined that creates the magnitude of the SO2 emission problem at Sudbury. At a production rate of 240 million pounds of nickel per year, Inco mines 12 million tonnes of ore. At 10% sulphur it mines 1.2 million tonnes per year of sulphur. If Inco did not fix any of this sulphur it would be emitting 2.4 million tonnes per year of sulphur dioxide-about as much as all other Canadian emissions. Today, however, Inco is already fixing 70% of the SO2 in ore, in several ways : mostly as sulphur in pyrrhotite rejected to tailings in the milling operations; as acid from the roasting of pyrrhotite and some nickel concentrate at the Iron Ore Recovery Plant (lORP) and some as liquid S02 from the copper flash smelting furnace. By fixing 70% of the sulphur the current allowable SO2 emission levels of 685 000 tonnes per year is met. Total sulphuric acid production is currently 450 000 tonnes per year and in fact, the 10RP operation is being continued only to maintain established acid markets.Historically emissions have been reduced from the 2 000 000 tonne per year level to the current level of 685 000 tonnes per year by rejecting pyrrhotite from the smelter feed, and 70% of the SO2 containment problem at Sudbury has already been addressed.While Inco's profits are large at current nickel prices, most people have forgotten that back in 1982 Inco was losing a million dollars a day. Inco did make a dramatic response to this economic stimulus. The Ontario Division increased productivity by 65% and lowered costs to become the lowest cost nickel producer."

Jan 1, 1990

By Doug Smith, Gary Taylor, Paul Ogryzlo

"Uranium mining and processing typically requires large quantities of high-grade reactive quicklime for the neutralization and clean-up of contaminated mine water and mill process waste streams. Currently the Saskatchewan uranium industry’s lime requirements are being supplied from deposits located in Manitoba and Alberta, resulting in transportation costs, which equal or exceed the market value of the product. During the summer of 2001, the northern village of Pinehouse located 220 kilometers south of the Key Lake uranium mill, staked two previously discovered limestone deposits. The relatively shallow deposits, known as Missi Island and Sleeping Giant are located in close proximity to one another, approximately 35 km south of Pinehouse adjacent to highway 914. This paper describes the results of a scoping study carried out by AMEC for the development of the two deposits based on a seasonal limestone mine and a continuous 40,000 to 60,000 tpy wood fired calcining plant designed to supply all of the quicklime needs of the Saskatchewan based uranium industry. Also described are the results of calcining and customer acceptance testwork on samples of lime prepared from recent Pinehouse limestone drill core. The potential benefits of the project include a significant new source of revenue for the community of Pinehouse, lower lime costs for the Saskatchewan uranium industry and employment for northerners in the mining, processing and wood harvesting operations.IntroductionInterest in the Pinehouse/Massinahigan River area for limestone was precipitated by the results of a 1977 industrial minerals drill hole program by the Saskatchewan Department of Mineral Resources. These results led to the acquisition of land in the area by Missi Island Mines Ltd who carried out extensive exploration during the period 1978-1982. They discovered a deposit on the southwest side of the Massinihigan River thought to contain approximately seven million tonnes of limestone with an average grade of 94.5% CaCO3. Missi Island carried out preliminary feasibility studies and prepared an Environmental Overview Statement. However, in spite of positive recommendations, the project was dropped in the mid 1980’s."

Jan 1, 2003

By Marko Lampi, Ross Andrews, Jouni Pihlasalo, Robert Matusewicz

With widespread discussion on reducing carbon, sulphur and other emissions, use of sustainable energy sources and the pivotal circular economy theme, consideration needs to be given to pyrometallurgical operations broadly and more specifically, non-ferrous metallurgy. These themes present a number of challenges in terms of current operations and the view of processing the metals which are largely taken for granted in day to day living. This paper considers how these themes will impact pyrometallurgical flowsheets using the non-ferrous base metals as an example. It will examine the flowsheet chain to offer views on the boundaries of flowsheet optimization and the application of available tools to meet these future goals and challenges. INTRODUCTION The themes of reducing footprint through lowered CO2, S and other emissions, together with process sustainability (e.g. lowered energy) and links to the circular economy are well known to everyone in the metals industries. Whether it is reducing greenhouse gas emissions or analysing the importance of metals recycling in the circular economy, all these themes carry with them the fundamental premise of any change being considered; how can you best optimize a system to meet your aims? Of course, this depends on the available tools and the approach used for optimisation.

Jan 1, 2019

By J. R. Bradfield

THOSE familiar with the development of the Horne mine can readily appreciate that more and more accommodation bas been required for underground labour as the mine has grown. A permanent fire-proof change house, 30ft. by 75 ft., was built in 1927 to accommodate 194 men. This was extended ro 30 ft. by 92 ft. in 1928 to accommodate 296 men, and to 30ft. by 110 ft. in 1930 to accommodate 398 men. By 1933 this building was again overcrowded and tentative plans for a new change house were drawn up. However, it was realized that future operations would be centred around No. 4 shaft and a proposed new shaft, and the decision as to the location of the new change house had to be deferred until the area which seemed most suitable for the new shaft had been thoroughly explored underground. In the spring of 1934, the basic idea was accepted of drying the wet clothes in open mesh compartments or baskets located between rows of standard steel street-clothes lockers and built so that the covers or lids would serve as seats or benches.

Jan 1, 1935

"7.1. Glossary of the Platinum-Group Minerals7.1.1. IntroductionA glossary of the platinum-group minerals (POM) serves as a useful introduction to a chapter on their mineralogy. Earlier glossaries (Cabri, 1972, 1976) were prepared for different purposes and composed in a different manner. As for most mineralogical textbooks, from Dana's System of Mineralogy, 3rd Edition (1850) , to Fleischer's Glossary of Mineral Species (1980), this glossary is primarily a chemical classification, arranged here in two tables. Table 7.1 groups the mineralforming compounds of the six platinum-group elements (POE) according to their essential anion(s) or according to the nonPOE element in intermetallic compounds. Table 7.2 is a similar listing for the native metals and alloys of the POE. Both tables include unidentified POM considered to be bona fide new minerals requiring additional study for complete characterization and recognition (see Chapter 9*). Some information on the chemistry of the POM is given in the sections on X-ray data (7 .2) and ore microscopy (7 .3). Because the overwhelming majority of POM have been characterized by the electron microprobe, a more detailed account of representative analyses is given in Chapter 8**. The total POM listed in Tables 7.1 and 7.2 is about 100, after deleting some which would not qualify as discrete species if found today, but which are still recognized on historical grounds; e.g. iridosmine, osmiridium, platiniridium. Tables 7.1 and 7.2 also include 28 unnamed POM; included because they are considered to be probably new species (Cabri 1981 b). The referral scheme for unnamed minerals is the same as in Chapter 9. There are considerably more palladium minerals known than other POM; the proportion of total species (listed in Tables 7.1 and 7 .2) for the POE is: Pd 48%, Pt 21 o/o , Ru and Ir 9% each, Rh 8% and Os 5%. These proportions are in marked contrast to the estimated cosmic abundance, as compiled for average type C1 chondrite by Naldrett and Duke (1980): Pt 29%, Ru 20%, Pd, Ir and Os 15% each, and Rh 6%."

Jan 1, 1979

By F. Habashi

Lead is an ancient metal. The alchemists related it to the planet Saturn. It was largely obtained by smelting galena which generally contains small quantities of silver. That is why the metallurgy of lead was closely related to that of silver and in some cases the ore was treated only for its silver content. It was also known during the Roman time that lead vapors were toxic. Lead has been produced exclusively by pryrometallurgical methods. Lead refining is a complex process because of the presence of deleterious impurities such as arsenic, antimony, and bismuth. In the nineteenth century lead played an important role as a material of construction in the manufacture of sulfuric acid. In the twentieth century tetraethyl lead was used exclusively as an anti-knock reagent. In recent years lead is mainly used for making batteries.

Jan 1, 2008

"Cambior currently has nearly 80 exploration properties, acting as operator on about 60 of these. The company's exploration budget has increased to over $11,100,000 for 1990. On-going efforts recently yielded a new gold discovery on the Douay- Vezza property, a joint venture project with Inco and Vior. Cambior continues to seek out new opportunities, recently acquiring an option agreement on the Sleeping Giant project in Quebec and four new exploration agreements in the United States, through its Reno office. Other nearly-concluded joint venture agreements have also given the company entries into Indonesia and Guyana.SummaryWhen it acquired SOQUEM's assets on August I, 1986, Cambior also acquired interests in 45 exploration projects. The subsequent mergers with Aiguebelle Resources and Sullivan Mines in 1987 brought the total number of exploration projects to 83, most of which are concentrated in northwestern Quebec. Cambior's strategy emphasizes gold exploration, and exploration activities were, therefore, initially limited to the Val d'Or and Rouyn-Noranda mining camps, where Cambior has a large portfolio of properties. Approximately $25.8 million has been spent on surface exploration in this area since the formation of the company, resulting in the discovery of the Mouska deposit and four sub-economic zones on the Porcupine, Forbex, Bloc Sud and Flavrian project s. In 1988, Cambior became involved in projects in the United States to which the company expects to allocate about 38070 of its 1989 exploration budget."

Jan 1, 1990

By V. L. Eardley-Wilmot

Introduction We are all familiar with the bright and attractive colours of the roofs of our suburban houses and country cottages, but few of us fully appreciate the complex and highly technical nature of the business which produces these roofings. Roofing granules consist of small broken particles of certain types of rocks, burned clay products, or slag. They are used either in their natural state or artificially coloured and are affixed onto one surface of asphalt sheeting. Their main functions are to protect the roof against external fire hazard, prolong its life, and enable it to withstand extremes of weather over a period of years without deteriorating. Pleasing designs and colours are added attractions. The reverse, or inner side, of the sheeting is coated with a film of talc or fine mica to prevent it sticking when rolled up for convenience of handling for transport. The finished sheets or strips are cut into a variety of shapes for roofing shingles, or for sidings which resemble rows of bricks separated by mortar. In Canada, the consumption of roofing granules has increased fourfold in the past decade and indications are that the industry will continue to expand. At present, fourteen plants are engaged in manufacturing granule-coated roofings, but, apart from a relatively small output of natural granules by two producers in British Columbia, only one eastern producer makes both natural and coloured granules in Canada, and these only for its own use. The annual consumption is now over 77,000 tons of roofing granules valued at more than $1,600,000, but about 62 per cent of the tonnage is imported. It is thus apparent that the production of Canadian-made granules, both natural and coloured, could be considerably increased. This paper is presented in order to give an outline of the industry and at the same time to point out its difficulties and pitfalls.

Jan 1, 1946

By K. Mayhew, K. Murray

The CESL Copper Process was developed as a hydrometallurgical alternative to smelting and refining for copper sulphide concentrates. As the majority of such concentrates contain appreciable gold and silver values, effective recovery of these metals is essential to the economics of this technology. Unfortunately, conventional cyanide processing cannot be used on the residue from the copper process, clue to its unusual characteristics when compared with naturally occurring gold and silver ores. An abundance of elemental sulphur, as well as the presence of cyanide soluble copper, leads to the formation of both thiocyanate and copper cyanide which is detrimental to process economics clue to excessive cyanide consumption. This, however, can be reduced to acceptable levels by process innovations such as pressure cyanidation and cyanide recovery. This paper outlines the successful application of the CESL Gold Process to various gold-bearing copper concentrates from bench to demonstration scale.

Jan 1, 2011

By J. E. Rowland

NIOCALITE is a new mineral species which has been identified in rock from the Oka district, Quebec. It occurs as prismatic crystals up to l 0 mm. in length and I mm. in width, in coarse, white, crystalline calcite with associated apatite, diopside, biotite, pyrochlore, and niobian perovskite. The crystals of niocalite are light yellow in col-our and have a vitreous lustre. The optical properties of niocalite (I) are as follows: Biaxial negative -2V = 56° a = 1.700, [ ] = 1.730 Birefringence y -a = 0.030 Optic orientation: X = b, Z/\c 12°, Y , /\a = 32° The specific gravity is 3.32 and the hardness is approximately 6 (Mohs scale). A detailed analysis performed on 2.4 gm. of hand-picked material reveals that niocalite is essentially a calcium niobium silicate. Table I gives the result of the analysis. Crystals of niocalite, apparently suitable for X-ray diffraction work, were selected, and single crystal photographs were obtained using both Weissenberg and Precession cameras. Initial difficulties were encountered in interpreting these films, and in correlating the crystal data with the optical data. The in-consistencies were explained by the fact that every grain examined was twinned to some extent.

Jan 1, 1957

By J. M. Paxton, R. L. Roscoe, G. A. McCreary, W. W. Muir, T. J. Drown, D. A. Barr, T. W. Law

"This paper reviews the complete cycle of a small mining operation in a remote section of northern British Columbia, including discovery, exploration, development and production. The discovery of high-grade epithermal gold-silver mineralization occurred in 1969 following a regional geochemical reconnaissance program designed to search for porphyry copper mineralization in the Cassiar-Omineca Mountains. Exploration and development from 1971 to 1979 included geological, geochemical and geophysical surveys; trenching, almost 30 000 feet of surface and underground drilling in about 100 holes and cross-cutting, drifting and raising on the principal goldsilver- bearing vein. This led to the delineation of 100000 tons at an estimated grade of0.9 oz gold per ton and 18 oz silver per [on to an average depth of 120 feet below surface. of a 100-ton per day mining operation employing about 50 personnel with all supporting infrastructure transported to the site by a Hercules aircraft. The operation was subsequently supported by its own Twin Otter aircraft with periodic Hercules campaigns supplying major items including fuel.The mining operation included both open-pit and cut-and-fill methods. The milling operation employed conventional cyanide leach process with cyanide destruction initially by alkali chlorination and subsequently by the Inco SOl /Air process.The fly-in operation, initially structured on a 21-day-in and 7-day-out basis was modified to al-t-day-in and Z-day-out basis with no loss in efficiency and with a significant increase in employee satisfaction. The operation, which earned the B.C. Small Mines Safety A ward in two consecutive years in its Ll-month operating history, emphasized safety and process hazard awareness. Wildlife studies in the environmentally sensitive mine area also showed that industry and wildlife can coexist in harmony.Most importantly, the paper compares the feasibility assumptions with actual operating experience."

Jan 1, 1986