Search Documents

By H. A. Doerner

"During the year which has passed since the last progress report on reduction of zinc by natural gas,3 the laboratory experiments on this investigation have been completed. In this concluding report, the whole subject will be reviewed and additional data presented.Chemical ReactionsIn a thermodynamic study of zinc smelting, Maier 4 discussed the use of methane for reducing zinc oxide, and predicted equilibria at various temperatures for the sore important reactions. The study has been extended to include the following list.Maier predicted that 870°C. would be the critical temperature above which reaction (1) would take precedence over reaction (2) and that reaction (1) at equilibria would be substantially complete at or above 927°C. A subsequent papers described experimental verification of these predictions and gave data on reaction rates under various conditions.It methane is passed through a heated bed of zinc oxide at a low enough rate reactions (1), (3), and (4) reach an equilibrium which can be expressed by reaction (10). The equilibrium concentrations for the products of this reaction in the temperature range 900° to 1100°C. were calculated by applying the thermodynamic constants to the stoichiometric relations. 6 The results of these calculations are listed in table 1 and shown graphically in figures 1, A and B. These data have major importance, and experimental work has shown that they are subtantially correct."

Dec 1, 1934

By H. Harzer

Statistics Canada record s indicate that in recent years 70 to 80% of the entire Canadian coal production originated from Western Canadian mines, in which about 55 to 65% of the coals are bituminous. Until recently, less than 20% of the latter were extracted by underground methods , the remainder being surface-mined. However, it is estimated that within the foreseeable future up to 80 or 90% will have to be gained by underground techniques. Although Western Canadian coal resources are considerable, they are unfortunately locked in severely distorted, steeply pitching and faulted seams of variable thickness. Consequently, their economic extraction poses serious engineering problems. One possible solution to the problems is to apply hydromechanical methods to underground mining. This is a well-proven method shown to be economically viable under Western Canadian conditions. This paper endeavours to widen the scope of published data on hydraulic coal mining and is based on practical engineering and cost data gathered through contacts with West German designers and operators of hydraulic mines.

Jan 1, 1978

By S. Kelebek, C. Gibson, M. Aghamirian

"Global niobium production is currently dominated by three operating mines, Araxá and Catalão in Brazil, and Niobec in Canada. Although over 90% of the world’s niobium is mined and processed in Brazil, a number of high grade niobium deposits exist worldwide. The advancement of these deposits depends largely on the development of operable beneficiation flowsheets. Pyrochlore, the primary niobium bearing mineral, is typically upgraded by flotation with amine collectors at acidic pH, and often includes a reverse gangue flotation stage prior to pyrochlore flotation. Challenges related to the flotation of niobium ores include complicated flowsheets which require pulp pH adjustment from alkaline to highly acidic conditions, difficulty recovering fine grained pyrochlore, producing concentrates that meet specifications, and minimizing the losses to reverse pre-flotation gangue concentrates, slimes, and tailings. The specific flotation challenges associated with different niobium ores are discussed. In some cases, the use of alternate flotation reagents and flowsheets are required to achieve reasonable gangue rejection and maximize recovery, particularly of very fine pyrochlore grains.INTRODUCTIONNiobium is a transition metal primarily found in the oxide minerals pyrochlore (Ca,Na)2Nb2O6(OH,F) and columbite (Fe,Mn)Nb2O6. After physical upgrading, pyrochlore is converted into a ferroniobium product which is largely used in the production of high strength low-alloy steel. Today’s niobium market is dominated by the Companhia Brasileira de Metalurgia e Mineração, whose Araxá operation produces over 80% of the world’s niobium. There are two smaller operations, Niobec in Canada, and Catalão in Brazil, which account for the remaining production (U.S. Geological Survey, 2013).A number of niobium deposits exist globally, their advancement dependent on the development of operable beneficiation flowsheets. Pyrochlore, the predominant niobium bearing mineral, is commonly upgraded by flotation with cationic amine collectors in acidic pulp conditions. However, many niobium ores do not respond to this typical flowsheet because they are either highly refractory or niobium deports to other minerals such as columbite, ilmenite and rutile, which are not as responsive to this reagent scheme (Bulatovic, 2010). Other reagents, such as alkyl hydroxamic acid, have been studied extensively and while promising, are not without their own inherent issues including lack of selectivity over iron oxide minerals, and high addition rates (Ni & Liu, 2012; Gorlovskii, Eropkiny, Koval, Strelstin, Khobotova, & Shtchukina, 1968; Gorlovskii, Khobatova, & Shtchukina, 1966).It is the aim of this report to highlight the challenges associated with the physical upgrading of niobium minerals through examination of the flotation behavior of two different ore systems. In order to overcome these challenges it is important to thoroughly understand the limitations of typical flowsheets/reagent schemes currently employed in operation."

Jan 1, 2015

By Dale Ramsey

Emulsion explosives have become the product of choice for many blasting applications and are not limited to just extreme wet hole conditions or special application environments as in the past. Today’s novel emulsion technology has evolved over many decades, allowing a great diversity of formulations, Emulsion explosives can be effectively designed to produce very high energies, cap sensitive high explosive cartridges to bulk blasting agents, with varying viscosities, stable VOD’s, excellent water resistance, long shelf life and sleep time. They are also conducive to the mixture of emulsion, An/F0 blends in varying proportions and are amenable to any type of sensitizer. The key to a stable, reliable and consistent emulsion formulation is the careful mixing of the internal phase, which consists of a solution of oxidizer salts suspended as microscopically fine droplets, with the surrounding continuous fuel phase. There are few blasting applications today where some form of an emulsion explosive cannot fit the application. In massive, hard rock, dense, tightly jointed and fine grained rock types, the emulsion explosives are the best choices in creating new fracture networks for good fragmentation with a few alternatives. In such environments, emulsions with expanded drill patterns often result in better economics than the use of straight AnLFo. This paper will cover emulsion formulations, sensitizing options, product testing, material handling, and blast optimization, Emulsion explosives characteristics have also proven to reduce adverse environmental effects such as noxious fumes, ground vibration, and airblast while still remaining cost effective.

Jan 1, 2000

By Daniel Lakovic

"Mining operations can create a negative environmental impact, especially when considering the tailings that are produced through the processing of ores. Tailings are finely grained residues that form sludges. The tailings are deposited into giant basins, or sludge ponds, where they create a burden on the environmentby limiting the use of processed water.Tailings are one of the most important environmental liabilities for mining operations because of their large proportion in relation to the ore mined — generally 90 to 98 percent. To get to the valuable minerals, mining companies must move large amounts of rock. The rock is ground and then treated, usually with the addition of chemical solutions and large amounts of water. The lower the concentration of the valuable resources, the greater the proportion of accumulated excavated material sludge.Sustainable tailings management requires responsible handling, making it one of the mining industry’s greatest challenges. The proper technology should include consistent control of the environmental risks and impacts, as well as a proper relationship with the communities that surround the mining operations.The tailings, which can remain partly contaminated with chemicals, are pumped into the large sludge basins, which are secured by earthworks. During the mining operations, the basins must be stable enough to withstand the pressure of the stored excavated material. The storage option is still used, but it has failed on occasion. And when it does, it increases the risks to the environment and binds the unused process water. The more complex the availability of fresh water required for industrial use and for human consumption and their economic activities — for example, farming and agriculture — the more complex the conflicts that have the potential to shut down mining operations. With modern separation technology solutions, it’s possible to process the sludge and recover the processed water. However, the responsible use of the water is critical. Therefore, mining companies must rely on technologies that allow for proper reclamation of the water, whether re-using in their own processes or treating it to return it to the environment."

Dec 1, 2018

By S. C. Sethi

The WIPP (Waste Isolation Pilot Plant) Project near Carlsbad, New Mexico, is a research and development project sponsored by U.S. Department of Energy, designed to demonstrate the safe containment for disposal of radioactive waste. A mine (repository) is currently being developed 2150 feet below the surface, in a thick salt bed which will serve as the disposal medium. Provision of a proper ventilation system at the WIPP Project is a major priority of those responsible for its design, management, and operations. As an ongoing effort towards this goal, it was decided to simulate the mine's ventilation system using Dravo's MINEVENT computer program. Specifically, the work included the development of the following simulation models: 1. Simulation of the current ventilation system 2. Simulation of the designed ventilation system for the following modes: o Mine Construction mode/shift o Waste storage mode/shift o Fire or exhaust filtration mode These computer models are useful in solving complex ventilation problems likely to be encountered in an R&D project, like WIPP. They are particularly helpful for the development of contingency plans to incorporate during emergency situations, such as fires, fan stop- pages, radiation leaks, etc. Also, they can be utilized when considering expanding certain underground areas to ensure the availability of adequate ventilation.

Jan 1, 1986

By B. K. Ayres

Modern management of uranium mine or mill waste storage facilities (WSFs) often requires that they be remediated or decommissioned with a cover system. In addition to creating a self-sustaining landscape that supports the end land use, cover systems are intended to reduce long-term risks to human and ecological receptors from the stored waste to acceptable levels. The performance and longevity of a cover system will be strongly influenced by the features or shapes of the WSF final landform. Hence, cover systems and landforms must be thought of as an integrated design. Based on the author’s experience, the most important elements of the design process for maximizing the potential of WSF final landforms / cover systems being sustainable over the long term are noted in this manuscript. Several key items that must be considered and addressed during the planning phase of constructing a WSF final landform are also described. Various methods for monitoring performance of a WSF final landform are also reviewed. Key aspects associated with decommissioning a tailings WSF and waste rock pile at the former Cluff Lake uranium mine in northern Saskatchewan are included to illustrate many of the practical insights provided in this paper.

Jan 1, 2020

By J Westh, S Rashleigh, L Gallagher

Mining companies are moving towards automated haul trucks and other equipment. One reason for this is that if automated trucks can operate in a standard pattern over and over again without variation, then human error is reduced, if not eliminated.The challenge for mining production leaders/managers is to ensure operators follow standard operating procedures for load and dump operations, with each operator doing the same thing, every time. However, operators are only human and inconsistent performance is rife at every mine site. The finger may be pointed at the operators for not doing as instructed. The clarity and variability of trainer instructions may be considered causal to the problem. Herein lies the problem. Almost all operators believe they are following the procedure very closely; moreover, they all demonstrate a strong desire to conform to instruction.Using video analysis and feedback, each operator can be shown where and by how much they differ from the benchmark set by their company. Operators, often for the first time, can see definitively what they are doing, compared to industry best practice.The technology utilised by real-time video (RTV) crews measures time, distance and angles. It can overlay the video of the operator at the load site, with video of the perfect pass. Operators are amazed when they see how near to, or how far they are from best practice.The footage and data gathered by RTV assists operators in understanding exactly what adjustments are required to increase proficiency. It also assists load and dump superintendents to identify where in the process they are losing time. When translated to overburden removal or mineral/resource extraction, the result is large production economies without the need for large capital investment in new automated technology.CITATION:Westh, J, Gallagher, L and Rashleigh, S, 2012. Improving safety and mine productivity using real-time video technology, in Proceedings International Mine Management 2012, pp 173-188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Michael J. Beus, Jan G. Patricio

INTRODUCTION The U.S. Bureau of Mines, Spokane Mining Research Center, has been conducting and documenting rock mechanics research in the Coeur d’Alene mining district for the past ten years (1, 2, 3, 4, 14, 15). A current project combines the information gathered from rock mechanics instrumentation, geologic structure, and analytic techniques to improve shaft and support design for the deep mines of the district (3). This project required knowledge of the anticipated loads and the physical properties of the rock mass to provide accurate input data for computer design models. Several techniques have been utilized to determine the physical parameters including the USGS (U.S. Geological Survey) solid inclusion probe, the CSIR (Council for Scientific and Industrial Research) biaxial and triaxial strain cells, and the CSM (Colorado School of Mines) dilatometer. This paper describes the determination of the in situ modulus of deformation in three mines over a period of three years and the evaluation of these results as they applied to this project. The need for in-situ rock mass properties such as the modulus of deformation has stimulated research and development of a large number of instrumentation techniques. One area of continuing interest involves various methods of radial borehole dilation. This concept was pursued by Menard (9) with an apparatus known as the pressure meter, which is used frequently in soil mechanics. Other developments in rock mechanics include the CPC (cylindrical pressure cell) by Panek (11) and the dilatometer by Rocha et.al. (13) in Portugal. The CSM dilatometer, which also utilizes this technique, was chosen for this project because it required a small amount of background study, was inexpensive, and could easily be combined with other experiments being planned for the test locations. Although no previous field applications to hard rock (compressive strengths greater than 20,000 psi) has been documented, the instrument was selected since good results have been achieved in granite, oil shale, and several coal measure rocks (11, 12).

Jan 1, 1977

As the theme of this conference is æRediscover OtagoÆ it would seem appropriate to revisit the era of the gold rushes and subsequent mining industry which rapidly advanced settlement and economic prosperity for Otago, and left permanent reminders in the form of historic mining sites, many of which are now encompassed within the Otago Goldfields Park. I have been invited to give a paper at this conference on the subject of æHistoric Goldfields of Central OtagoÆ. As well as having a working involvement with historic areas through my employment with the Department of Conservation, I have a personal interest in the early goldmining industry of Central Otago as my grandfather came out from Scotland in the 1890s to help construct gold dredges on the Molyneux. My grandfather made headlines in the local paper in 1920 when he believed he saw a New Zealand otter at Island Block near Beaumont - but that's another conservation trail that I will not pursue any further today! For this paper I intend to divide my time to cover the following topics. Firstly, I would like to sketch a mental picture of the characteristics that make up the Central Otago landscape, and the general perception that early miners must have had when viewing this foreign land. Then I would like to briefly discuss the changes and the consequences in the early gold rush to Central. Finally, I would like+ to discuss the establishment of the Otago Goldfields Park, which I will illustrate with several slides.

Jan 1, 1992

By William J. Wuest

This U.S. Bureau of Mines report presents an overview of ground control considerations associated with floor heave. Factors affecting heave, such as in situ stress, floor characteristics, and mine geometry, are described. Floor-displacement monitoring and data analysis methods are outlined. Finally, floor heave remediation is discussed. The remedial techniques are divided into four categories: mine maintenance, supplemental support, mine structure, and techniques for multiple-seam operations. Other subjects covered in the report include laboratory and in-place testing of floor rocks, U.S. and international case studies, effects of mine layout, determination of excess horizontal pressure, and types of heave failure. The emphasis of this report is on practical considerations; theoretical discussions are kept to a minimum.

Jan 1, 1992

By Frank E. Sullivan

The separation of liquids from granular materials has been widely studied by a number of: investigators over a period of years in an effort to more fully understand the physical phenomenon which occurs. Liquid may be removed from solids, or partially removed, by gravity separation, mechanical separation' or heat drying. Mechanical separation is advantageous when compared to heat drying principally from a cost saving standpoint and also on certain materials which are heat sensitive. It is realized however that mechanical separation of liquids has certain practical limitations. In order to evaluate the efficiency of mechanical separation and predict the extent of, liquid removal, it is first necessary to study the forces which hold the liquid to the solids. From a very practical observation using gravity drainage, it is soon obvious that a pile of coarse solids will drain faster and retain less liquid than a pile of finely divided solids of the same material. For commercial operations it is important to estimate the residual liquid which will remain after a mechanical separation. Batel (1) explored the various quantities of liquid present in the interstices of the bulk granular material. From his work and other authors which he has correlated in one of his recent papers, various formulas are now available which permit an empirical relationship to be developed showing residual moisture versus mechanical separating forces.

Jan 1, 1965

By J. C. Uy, T. E. Davidson, A. P. Lee

The effects of hydrostatic pressures to 26 kbars on the micro structure of poly crystalline Cd, Zn, Bi, Sn, Zr, Mg, Cu, and Fe were examined. Pressure-induced microscopic plastic flow in the form of boundary migration, slip, multiple slip, or twinning has been observed either singly or in combination in cadmium, zinc, bismuth, and tin. No deformation was observed in zirconium, magnesium, copper, and iron. The occurrence of such deformation, in terms of its intensity and initiation pressure, relates directly to the degree of anisotropy in the linear compressibility. Pressure cycling does not significantly affect the residual tensile properties of a zinc alloy which exhibits pressure-induced deformation similar to that of Pure zinc. CLASSICAL elastic theory predicts that a superim-posed hydrostatic pressure will not induce shear stresses in an ideal material. Thus, in the case of homogeneous and isotropic materials plastic flow will not occur as a result of pressure exposure, regardless of the magnitude of the pressure, unless some form of phase transformation or permanent density change takes place. However, real materials, such as metals, often vary considerably from the condition of homogeneity and isotropy. For this reason, Vu and johannin' examined and observed hydrostatic pressure-induced microscopic deformation in polycrystalline cadmium and, zinc, but not in aluminum, to pressures of 9 kbars and indicated that its occurrence is related to anisotropy in the linear compressibility. In addition, Davidson and omaan' have reported pressure-induced deformation in polycrystalline bismuth below the 1-11 transformation pressure. It becomes apparent then that under certain conditions hydrostatic pressure can induce localized internal shear stresses in some metals of sufficient magnitude to cause plastic flow. In this work, eight pure single-phase metals of different lattice structures and degrees of elastic anisotropy were examined after pressure exposures of up to 26 kbars in order to establish the conditions under which such deformation occurs and the type of deformation as a function of pressure. The effects of pressure cycling on the mechanical proper-

Jan 1, 1965

By H. De Cizancourt

The Pechelbronn (Alsace) field is the only important French producing field. During 1934, development was carried on as in previous years. The total output of this field reached 553,575 bbl. in 1934, showing a slight decrease from the 1933 figures. Of the total, 315,000 bbl. (56 per cent) was extracted by drilling, while 238,875 bbl. (46 per cent) was obtained by means of shafts and galleries. Exploration of deep Jurassic and Triassic horizons was still in progress at the end of 1934. A deep well reached the Upper Triassic at a depth of 34 m. (2736 ft.). (Information kindly supplied by M. S. Mena, Directeur Technique.) As mentioned before, the small Gabian field (Herault) is gradually being exhausted. No drilling operations were undertaken in 1934, the small production being restricted to the pumping of old wells. Two exploration wells, noted as "drilling" at the end of 1933, were completed in 1934; viz., Lavelanet (Ariége) at 3785 ft. and Santenay (Niévre) at 2578 feet. French Possessions Algeria.—No drilling at Tliouanet. Out of a total of 100 wells drilled in the area, only 8 are still producing. No exploration work is reported during 1934 in Algeria. Tunisia.—Two wells completed; one well drilling at the end of 1934. A total of 11 wells is reported to have been drilled before the beginning of 1935; out of these, 8 were completed before the present program was begun. Morocco.—Exploration work progressed actively last year. The outstanding event was the coming in of Ts. 26 well at 1243 ft. This well took fire, therefore great difficulties were encountered in the accurate measurement of initial production; the figure of 1500 bbl. of oil given here is a near estimate. Oil flowed accompanied by a great amount of water. The apparent decrease of drilling operations in 1934 is explained by the increase in field activities after the results of Ts. 26 were known;

Jan 1, 1935

By Robert B. Parsons

"Canada's mining industry has reason to celebrate the federal government's budget which was tabled on February 26, 1986. The budget contains an important proposal to improve the flowthrough share rules by effectively eliminating the investor's liability to third parties. This proposed rule change and other important budget proposals are the subject of this month's edition of Tax Notes. IntroductionWhile Finance Minister Michael Wilson's February 26, 1986 budget received a mixed reaction from business and labour leaders, the budget was mainly ""good news"" for the mining industry. A long-standing bugaboo in the flow-through share rules will be cleared up, a permanent set of rules will be installed for the tax treatment of Northern allowances, and limited partnerships will apparently be able to continue to serve a useful role in financing exploration programs. Flow-Through SharesThe present rules which apply to an investment in flow-through shares are structured in such a way that the relevant Canadian exploration expense (""CEE"") must be incurred by the investor, and not by the issuing corporation. Obviously, in the case of most flow-through share issues, this requirement that the investor incur the CEE poses a practical problem-the investor typically does not have the expertise or organization to incur the CEE. As a result, an integral part of most flowthrough arrangements is an agreement whereby the investor appoints another party (usually the issuing corporation) as his agent to spend the flow-through funds on CEE on his behalf. Although the issuing corporation might consequently be the party which actually spends the flow-through share funds on CEE, nevertheless the legal structure is such that the investor is the ""principal"" who is incurring the CEE. As such, the investor is legally responsible for any third-party claims with respect to the exploration program. Third-party liability might arise, for example, in the case of property damage, personal injury, environmental infractions, and so on."

Jan 1, 1986

Threshold blasting involves the use of small amounts of high explosive to break and fragment hard rock without having to evacuate mining personnel. The method is easily assimilated and effective in rockbreaking, but requires rigid control on drilling, charging and timing. Current underground trials are aimed at fine-tuning the amount of explosive energy and blast hole geometry to allow the firing of multiple sets of shot holes in a continuous manner. Through correct procedures, the after-blast fumes, dust and fly rock can be contained so as to provide a safe working environment. Threshold blasting hugely reduces the volumes of explosives used in mining and brings to maturity the potential of the process begun by Alfred Nobel when he introduced nitroglycerine, and later dynamite, to mining. Its key contribution is its enabling of continuous mining operations with well understood and relatively low cost technologies. The use of batch blasting, employing large burdens holds the greatest potential for delivering high flow rates of ore at minimal cost. There is good potential for rapid evolution of the concept.

Jan 1, 2002

By James W. Marold

Tunnel and shaft plugs have been designed to assist in construction of new and rehabilitation of existing tunnels and shafts. Tunnel plugs have been used to provide construction access for side by side tunnels, separation of raw and treated water, and to allow operation of one tunnel during construction of a nearby tunnel. Shaft plugs have been used to seal up surface openings to tunnels and to prevent seepage of water to the surface through adjacent tunnels or shafts. The design construction details of tunnel and shaft plugs are provided. Typical examples of tunnel and shaft plugs are provided.

Jan 1, 2008

By T Baumgartl, R Akesseh, M Edraki, B Usher, M Shaygan

With the continuing demand for industrialisation and urbanisation, the rate of mining and processing lower grade ores will also increase, producing large quantities of waste. As extreme weather events associated with global climatic changes are to be expected, the risk from mine tailings management will also increase (Edraki et al., 2014). In sulfide rich tailings, weathering within the critical zone controls the fate and distribution of the contaminants such as copper, zinc, and lead in the environment (Hayes et al., 2014). Tailings evolve geochemically and physically with time as they age under the influence of complex interacting factors. Understanding of the complex interactions between these controlling factors is important for predicting and mitigating the potential risks associated with sulfide tailings such as generation of acid mine drainage (Lindsay et al., 2015). Wetting and drying initiates weathering processes, influencing the hydrological, geochemical and geomechanical properties of the tailings. In semi-arid climates where evaporation exceeds precipitation, salts may precipitate within the pore system as well as on the tailings surface. These salts become the temporal sink of heavy metals until the next episodic rainfall (Nordstrom, 2011, Grover et al., 2016). Therefore, using kinetic and static test to describe the trajectory of these material evolutions without considering the complex interactions could potentially lead to erroneous prediction. In order to understand these relations, the effect of drying and wetting cycles on the hydrological, geochemical and geomechanical properties of ageing tailings was studied to draw conclusions for advanced tailings site rehabilitation and mine closureCITATION:Akesseh, R, Shaygan, M, Usher, B, Edraki, M and Baumgartl, T, 2018. Wetting and drying cycles as a means to determine the effect and consequences of tailings ageing, in Proceedings Life-of-Mine 2018, pp 24–27 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Owen Matthews

THE property of Cochenour Willans Gold Mines, Limited, is in Dome township, Red Lake area, northwestern Ontario, a hundred miles north of Kenora and close to the Manitoba border. 'Planes of Canadian Pacific Air Lines, Limited, serve the district daily, except Sundays, from Kenora, Ontario, and Lac du Bonnet, Manitoba, passengers being trans-ported from Winnipeg to Lac du Bonnet by car. Freight is handled by the Patricia Transportation Company. It is brought in from Hudson, Ontario, on the Canadian National railway, in summer by water and in winter by tractor trains over the frozen lakes. The first staking on the property was done during the 'rush' of 1926 and 1927 by William M. Cochenour, and on April 30th, 1928, a syndicate was formed, taking in claims of W. M. Cochenour and Dan Willans and H. G. Young. Surface trenching was carried on almost continuously until 1934. In October, 1932, Ventures Limited took an option on the property, and in December of that year they carried out an extensive diamond drilling programme, but considering the results did not justify further work, they relinquished the option. In July, 1934, further surface work was carried out under the supervision of W. P. Mackle and, on the strength of his report, Noah Timmins Incorporated took an option on the property and agreed to make an initial expenditure of $100,000 on development work. This was carried out under the direction of Hollinger Consolidated Gold Mines and included the sinking of a shaft to a depth of 165 feet, establishment of a level at the 150-foot horizon, and some 1,900 lineal feet of drifting and cross-cutting. The results obtained from this work were not considered of sufficient promise and the option was terminated in August, 1935. Mr. Cochenour then approached Alex Mackenzie and associates, and the present Company, Cochenour Willans Gold Mines, Limited, was organized on April 9th, 1936, and sufficient money was raised to continue operations. Under the direction of W. P. Mackle, the shaft was deepened and a second level was established at the 275-foot horizon; but, due to several adverse reports by outside engineers, it was found impossible to raise sufficient money to carry on the work and operations were suspended in December, 1937. In January, 1939, an agreement was entered into with Gold Eagle Gold Mines for the milling in their plant of some Cochenour ore. A total of 4,959 tons was treated, and the results were so encouraging that further finances were raised by C. A. Gentles & Company, of Toronto. Following further development in the mine, it was decided to erect a mill. Construction was started on September 1st and the mill was turned over on November 29th. The first gold brick was poured on December 23rd.

Jan 1, 1942

By Richard W. Hutchinson, Robert W. Hodder

"Pyritic massive sulphide deposits lie conformably above submarine volcanic rocks, and beneath siliceous and manganiferous iron formations. The massive bodies are often zoned, with a barren pyritic top grading downward into pyrite with sphalerite, and occasionally galena, and a chalcopyrite-rich base. They are frequently brecciated, like the lavas beneath them, which contain pyrite and chalcopyrite as coatings on joints and fractures and as dispersed grains. The lavas also exhibit propylitic, argillic and silicic alteration. These sulphide deposits appear to have formed on sea bottom from fluids escaping through the lavas during periods of exhalative and sometimes explosive volcanism. The process may be comparable to the present deposition of base metals from hot brines in the Red Sea. Some porphyry copper deposits resemble the altered, sulphide-impregnated lavas which lie beneath bodies of pyritic massive sulphide. In porphyry copper deposits, pyrite and chalcopyrite occur as veinlets and dispersed grains in intensely fractured tuffs, flows, sub-volcanic intrusions or other host rocks, characterized by propylitic, argillic and silicic alteration. Metal zoning is present; sphalerite and galena often occur in manganiferous veins peripheral to a shell of pyritic veinlets which encloses the mineable zone of chalcopyrite-bearing veinlets. This sulphide distribution appears to have formed from hydrothermal fluids escaping, either passively or violently, from solidifying magma. The fluids may be comparable to hot brines encountered by drilling in the Salton Sea area of California.There are also important differences between massive sulphide and porphyry copper deposits. The former usually occur in differentiated, mafic-to-felsic subaqueous volcanic rocks, whereas porphyry copper deposits are often associated with shallow plutons and subaerial volcanic rocks of intermediate to felsic composition. Calcic-sodic metasomatism accompanies the massive sulphides, whereas potassic metasomatism characterizes the porphyry cop.per deposits. Further, ages of massive sulphides range from Archean (Keewatin) to Tertiary, but porphyry coppers are Triassic to Tertiary in age. These similarities and differences suggest that massive sulphide and porphyry copper deposits are related tectonically and metallogenetically. The former were generated during early stages of crustal evolution, particularly in Archean time, and were repeatedly derived during early stages of younger, individual tectonic cycles. In contrast, the porphyry coppers developed during the later stages of crustal evolution - later in terms of both absolute age and relative age within younger individual tectonic cycles. They appear in younger rocks generally, and specifically in rocks involved in events of the middle and late tectonic stages of orogenic belts. The massive sulphide deposits are of early-magmatic eugeosynclinal affiliation, whereas the porphyry deposits formed in late-magmatic, predominantly subvolcanic settings at the edge of continental plates, where contemporaneous exhalative volcanism was mainly a subaerial phenomenon. Transitional types of deposits exist and are found on continental margins with flanking eugeosynclinal sequences."

Jan 1, 1972