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By M. Peshko, J. C. Gingerich, L. W. Matthews

"Noranda has successfully developed and implemented two leading-edge mineral exploration technologies — hyperspectral remote sensing and 3-D seismic surveying. Airborne hyperspectral imaging provides detailed geological and mineralogical mapping capability at both a regional and project scale that facilitates improved selection of prospective terrain and an accelerated exploration cycle. Noranda, in partnership with Falconbridge, has licensed the exclusive use of the Earth Search Sciences Inc. (ESSI) Probe-1 hyperspectral scanners (128- channel, 0.43 µm to 2.5 µm spectral range) that are capable of mapping in excess of 3500 km2 per day at 10 m pixel resolution. The technology has been successfully deployed on four continents over a broad range of terrain from desert to boreal forest and the high Arctic.To augment the company’s deep search initiatives, Noranda has successfully modified and implemented existing 3-D seismic technology to help targeting massive sulphides located at depths ranging from 500 m to 2000 m. In the fall of 1998 and early 1999, Noranda completed an 18 km2, 3-D seismic program in eastern Canada by successfully drill testing acoustic impedance anomalies locating massive sulphides at depths in excess of 1100 m."

Jan 1, 2002

By C. H. van Eendenburg

"Installation of a 3.6 km long raw coal conveyor in the Balmer open pit was undertaken to improve over-all haulage efficiency. This paper covers the rationale behind this project, system design and construction aspects and initial operating experiences. The majority of the construction work was performed by our own personnel. Where feasible, used equipment was installed to reduce capital cost and facilitate a tight construction schedule.BackgroundWestar Mining Ltd's Balmer Mine is located in the British Columbia Rockies, just outside of the town of Sparwood in the southeastern corner of British Columbia. The open pit mine, which has been in operation since 1969, currently produces about 6 million clean tonnes of coal per year, mostly for the metallurgical coal export market. Run-of-mine coal tonnages total between 9 and 9.5 million annually and waste removal volumes exceed 30 million bank cubic metres.The mine is a truck/shovel operation; loading equipment includes nine electric shovels, five front-end loaders and a hydraulic backhoe. The truck fleet consists of 40 units of 154-tonne, 181-tonne and 315-tonne capacity. The newer 154-tonne trucks are used for coal haulage for which they have been equipped , with tailgates to maximize their coal carrying capacity."

Jan 1, 1990

By Gilles Bonin

Structures and serpentinization patterns in the Thetford Mines peridotites are important characteristics indicating the necessary geological conditions which led to the development of chrysotile orebodies in Early Ordovician limes. These structures and serpentinization patterns are reviewed in this paper using the geology of LAB Chrysotile orebodies as a model. Structural aspects include parallel and transverse faults, parallel and transverse granite slabs, and orebodies, some of which trend clearly north-westward parallel to the accretionarymovement. Serpentinization patterns in the peridotite belt, particularly in the harzburgite, include primary pervasive mass serpentinization and secondary complete serpentinization. Listwaenites layers appeared along some faults and along some granite slabs as a result of hydrothermal alteration of the serpentine, following the emplacement of the devonian plutons to the south. These plutons as we/1 as other important lineaments, align with the structural pattern of Thetford Mines ophiolites. It is believed that these plutons are part of a heavy magma tic corridor resembling the Pilote-Mont-Louis corridor in the Gaspe (Doyon and Berger, 1997), and the Buchans' structure in Newfoundland (Hutchinson, 1984), both intersecting the Brompton-Baie Verte line.

Jan 1, 2001

By H. L. Cheng, C. H. B. Leitch, C. T. Hood, A. J. Sinclair

"Epithermal Zn-Pb-Cu-Ag-Au quartz-carbonate-barite veins at the Silver Queen mine near Owen Lake, west-central British Columbia, are hosted by Late Cretaceous Tip Top Hill andesitic volcanic rocks. The veins form a rectilinear northwest-northeast pattern that differs slightly from regional structural trends. The main northwest-trending veins are oriented very close to the trend of regional northwest faults, but the crossing veins tend to be more east-north-easterly (070 degrees)compared to a regional north-easterly trend (040 degrees). The character of the veins suggests they are extensional features formed by dextral slip related to Paleogene oblique subduction, or intrusion of magma at depth, or both.In detailed exploration at the mine, the veins cannot be modelled as simple tabular sheet-like bodies. Instead, they are complex structures that divide and rejoin, forming multiple veins or stringers, or are found in shear zones as replacement features with quartzsericite- clay-carbonate-pyrite alteration haloes of variable width that make definition of vein margins and correlation from hole to hole ambiguous. In addition, individual veins within each of the main structures have en echelon characterboth along strike and down dip.Geological and assay data must be carefully studied to define the margins of these complex veins before any estimation of ore reserves may be made. Where multiple veins occur in a section, ore/gangue mineralogy, assays, character of wallrock alteration, and thickness of vein and mineralized hangingwall, median and footwall zones must be used to evaluate continuity of mineralized structures. Well-defined sections are projected into areas of increasing complexity. Once the vein boundaries are defined, metal concentrations, important metal ratios(Au/Ag, Pb/Zn, Cu/Zn), and true thicknesses of the vein provide the basic data for reliable ore reserve estimation."

Jan 1, 1991

By Catharine E. G. Farrow, David H. Watkinson

The Ni-rich Epidote Zone of the Fraser Mine at Sudbury is characterized by alteration assemblages rich in epidote, actinolite and magnetite which are roughly concentrically zoned and up to hundreds of meters in length. These zones form discrete areas within the igneous Footwall Breccia below the Sudbury Igneous Complex. The assemblages grade from epidotized Footwall Breccia matrix,through actinolite-bearing rocks with few vestiges of original Footwall Breccia textures, into the most intensely altered rock, a magnetite-rich facies. Pentlandite, pyrrhotite and pyrite are the dominant sulfdeminerals; chalcopyrite is minor. The strongest geochemical differences compared to original Footwall Breccia occur where epidote and actinolite dominate the alteration assemblage (EPDZact facies). The most intense alteration facies are typifed by low Cu/(Cu+Ni) values of <0.1. Strong positive correlations exist between Ni and Co, Cu and Au, and among Ir, Os, Ru and Rh. Chondrite-normalized Ni - PGE -Au - Cu plots display an overall increase in all elements from the least to the most intensely altered facies except for Au and Cu. As the proportion of actinolite increases in the EPDZact facies, the chondrite-normalized profles fatten considerably due to low Au and Cu contents. Abundances of Ni, Ir, Ru and Rhalmost ubiquitously increase with degree of alteration. In contrast, Cu, Zn, Ag and Au contents are low in almost all facies. It is suggested that saline hydrothermal fluids moved through the Epidote Zone formation and became more oxidized as they reacted with the Footwall Breccia and with footwall units, including ultramafic rocks. As this trend continued, magnetite-rich zones eventually developed. The occurrence of calcite locally in these magnetite-rich zones suggests that the pH of the fluid increased, causing Cu solubility to drop as activity in the hydrothermal system waned. Sudden changes in fluid composition such as this may have been due to an influx of fluid from bounding ultramafic rocks. Hydrothermal activity was focused along the margins of footwall ultramafic units. Individual hydrother-mal cells may have formed in the Footwall Breccia along pre-existing structures or sulfde concentrations. Metals may have been scavenged from sulfide-bearing Footwall Breccia and possibly Sublayer rocks. Nickel and some PGE were deposited in the Epidote Zone, whereas Cu, Au and Ag continued out-ward into the footwall where they were deposited as Cu-rich footwall veins. Copyright © 1996 Canadian Institute of Mining, Metallurgy and Petroleum.

Jan 1, 1996

By Catharine E. G. Farrow, David H. Watkinson

Abstract-The Ni-rich Epidote Zone of the Fraser Mine at Sudbury is characterized by alteration assemblages rich in epidote, actinolite and magnetite which are roughly concentrically zoned and up to hundreds of meters in length. These zones form discrete areas within the igneous Footwall Breccia below the Sudbury Igneous Complex. The assemblages grade from epidotized Footwall Breccia matrix, through actinolite-bearing rocks with few vestiges of original Footwall Breccia textures, into the most intensely altered rock, a magnetite-rich facies. Pentlandite, pyrrhotite and pyrite are the dominant sulfide minerals; chalcopyrite is minor. The strongest geochemical differences compared to original Footwall Breccia occur where epidote and actinolite dominate the alteration assemblage (EPDZact facies). The most intense alteration facies are typified by low Cu/(Cu+Ni) values of <0.1. Strong positive correlations exist between Ni and Co, Cu and Au, and among Ir, Os, Ru and Rh. Chondrite-normalized Ni - PGE - Au - Cu plots display an overall increase in all elements from the least to the most intensely altered facies except for Au and Cu. As the proportion of actinolite increases in the EPDZact facies, the chondrite-normalized profiles flatten considerably due to low Au and Cu contents. Abundances of Ni, Ir, Ru and Rh almost ubiquitously increase with degree of alteration. In contrast, Cu, Zn, Ag and Au contents are low in almost all facies. It is suggested that saline hydrothermal fluids moved through the Epidote Zone formation and became more oxidized as they reacted with the Footwall Breccia and with footwall units, including ultramafic rocks. As this trend continued, magnetite-rich zones eventually developed. The occurrence of calcite locally in these magnetite-rich zones suggests that the pH of the fluid increased, causing Cu solubility to drop as activity in the hydrothermal system waned. Sudden changes in fluid composition such as this may have been due to an influx of fluid from bounding ultramafic rocks. Hydrothermal activity was focused along the margins of footwall ultramafic units. Individual hydrothermal cells may have formed in the Footwall Breccia along pre-existing structures or sulfide concentrations. Metals may have been scavenged from sulfide-bearing Footwall Breccia and possibly Sublayer rocks. Nickel and some PGE were deposited in the Epidote Zone, whereas Cu, Au and Ag continued outward into the footwall where they were deposited as Cu-rich footwall veins.

Jan 1, 1996

By R W. Hutchinson

Cupreous pyrite deposits in Cyprus have many geologic similarities to Canadian massive sulphide copper-zinc ores as well as certain significant differences. A comparison of the Cyprus and Canadian deposits indicates a complex genetic history for the latter and suggests that their origin should be re-examined. The Cyprus ores occur in subaqueous extrusive rocks near and at the top of a Cretaceous volcanic pile or igneous complex. The rocks have not been deformed, nor have they been deeply buried or deeply eroded. Apparently the ores formed near or at surface in the top of the volcanic pile by a volcanic-exhalative process and from an ore-fluid of volcanic derivation. The Canadian deposits are of comparable composition and have similar geologic set-tings, but occur in the most ancient Precambrian rocks. Their enclosing Keewatin greenstones have, in most places, been deformed, regionally metamorphosed and invaded by granitic intrusions. Comparison suggests that the Canadian ores also formed initially near surface in ancient Keewatin volcanic complexes by a syngenetic, volcanic-exhalative process. Subsequently, during orogenesis, they were deformed, remobilized under conditions of elevated pressure-temperature and re-emplaced as epigenetic bodies into

Jan 1, 1965

IN 1932, the No. 4 shaft at Wright-Hargreaves mine was completed to a depth of 4,000 feet, and the lowest operating level at that time was at 3,900 feet. It was realized that the existing pumping system, using triplex plunger pumps at somewhat irregular depths in the mine, would be in-adequate to take care of the increasing volume of water that would have to be handled as mining operations expanded. Accordingly, in February, 1932, after a thorough study of the whole matter, it was decided to instal an entirely new, automatically controlled, system of pumping, employing centrifugal pumps, with their characteristically trouble-free performance, operated by off-peak power.

Jan 1, 1939

By J. F. Wright

INTRODUCTION Eighteen years ago about half a dozen experienced prospectors moved from northern Ontario to northwest Manitoba to prospect &apos;greenstone&apos; areas shown on geological maps of .parts of northern Manitoba prepared by J. B. Tyrrell, D. B. Dowling, and Wm. Mclnnes. Gold-bearing quartz was soon discovered by these men in this new field, and in succeeding years many more prospectors entered the district. A number of the pioneers are still prospecting, and since 1913 mineral deposits have been discovered each year in widely separated areas of the large district extending 150 miles eastward from the 102nd meridian and 60 miles north of latitude 54°30&apos;. The majority of the discoveries, however, have been made near Schist, Elbow, Wekusko, and Kississing lakes. One hundred or more mineral occurrences of some merit are known, the main types being sulphide replacement bodies containing nickel-copper or copper-zinc and gold-bearing quartz veins. Some underground exploration or diamond drilling has been completed on 25 or more of the prospects. Up to the present, three ore-bodies, namely, Flin Flon, Sherritt-Gordon, and Mandy, have been proved. Of these, Flin Flon, the largest, is estimated to contain from 16,000,000 o 19,000,000 tons of copper-zinc ore carrying some gold, silver, and lead. Next in importance in regard to tonnage is Sherritt-Gordon, with a calculated reserve of nearly 5,250,000 tons of copper-zinc ore carrying less than $1.00 combined gold and silver.

Jan 1, 1931

By James D. Hall

THE Dome ore-bodies are more or less isolated and are mined. by shrinkage stoping. An interwoven system of veins is mined at Hollinger &apos;.1.nd requires close filling. Deep mining is the problem at McIntyre. Dome ore contains a large amount of free gold, which is recovered on blankets. An all-cyanide flow-sheet is \lSed in the Hollinger mill. Flotation concentration is an important feature of McIntyre mill operation. Therefore, these three mines afford an unusual opportunity to compare gold mining and milling methods. The purpose of this paper is to describe the conditions existing at the Dome, Hollinger, and McIntyre mines and to outline the mining and milling practice at each property. Figures 3, 4, 5, and 7 are reproduced from the Canadian Mining ]011rna/, September, 1935 (Young, A. W., Mining at Hollinger), and Figures 8 to 11 from the Engineering and Mining Journal, November, 1933 (Keeley, D. E., Development and Mining at McIntyre). The photographs (Figures 6, 12, and 13) are by The Canadian Government Motion Picture Bureau. Diagrams of the several mill flow-sheets, which formed a part of the original paper, are not reproduced here. They will be found in Dorr&apos;s Cyanidation and Concentration of Gold and Silver Ores.

Jan 1, 1938

By Edgar Dernedde

Cryolitic melts at a temperature of about 960 °C are used in reduction cells to dissolve alumina and to produce primary aluminium. At these temperatures cryolitic melts with an acidic composition have a significant vapour pressure, which contributes substantially to the evolution of fluorides from these cells, The Antoine equation is commonly used for relating vapour pressure data of liquids at different temperatures, It is also applicable to cryolitic melts, Published equations have at least 20 numerical constants, in order to allow for the effects of melt composition. In the present work a simplified equation with only 12 numerical constants was developed and is applicable for multiple additions to molten cryolite up to 30 wt %, The simplified equation was compared with the published equations of Haupin & Kvande and Gustaysen & Ostvold using 472 vapour pressure data of cryolitic melts. Results showed that the simplified equation has the same accuracy as the published equations in the composition range of interest to industry.

Jan 1, 2004

By Neville Jordison

Indirect, gravity flow, heat exchangers have become a well established technology in mineral and metallurgical process plants. The technology is a conventional heat exchanger using high efficiency plates, with a free flowing bulk solid on one side of the exchanger and a fluid on the other side. This simple concept leads to many opportunities for achieving greater energy efficiencies in process plants. Indirect heat exchange is much more efficient than direct heat exchange using air such as in a fluid bed or rotary device. When air is used directly, large fans are required, it may also be necessary to chill the air, both high consumers of energy. By contrast, using water as the cooling medium requires only low horsepower pumps, typically only 10% of fan HP. Furthermore there are no stack emissions with the requirement for removal of dust or emissions. Indirect heat exchange also creates the opportunity to recover energy. This can work in two ways: energy can be recovered from a hot bulk solid, to heat pressurized hot water for steam generation or preheat air. Alternatively recovered energy from elsewhere in the plant in the form of hot water, steam, air or thermal oil can be used to preheat a bulk solid.

Jan 1, 2011

By N. R. Paterson

"More than a dozen AEM systems are currently being used in the routine exploration for massive sulphides. The systems differ from one another in minor respects, but fall into four main categories: rigid-coupled in-phase/quadrature systems; towed-bird, single-component systems; differential systems; and passive systems.Although field tests are important in demonstrating the performance characteristics of the AEM/airframe assembly (noise-levels, coupling effects, etc.), more meaningful evaluations can be made through physical or computer modelling. The latter approach has been used to compare the response of twelve AEM systems to both vertical and horizontal sheets, simulating a large orebody and a con-ductive overburden respectively. The effects of height changes are also studied.The results demonstrate that each AEM system has its own particular advantages and disadvantages. The relative importance of these is a matter for the geophysicist to judge, on the basis of specific geological and environ-mental information. Data currently available on AEM systems are adequate to permit an objective evaluation of the systems for a particular exploration program."

Jan 1, 1971

"The ventilation-related risks from mines with elemental sulphur include dust explosions, spontaneous combustion with emission of heat and toxic sulphur dioxide or hydrogen sulphide gases, reactions with nitrates, corrosion, acid water, and pyrophoric reactions with naked iron or other metals. Elemental sulphur will form explosive mixtures in air at lower dust concentrations and at lower ignition temperatures than coal or sulphide dusts. Potential controls include primary ventilation circuit design, control of dust deposition and static discharges, enclosing steel surfaces, inert stone dusting, FRAS ducting, humidifying the air, alternate stench gas, self-contained self-rescuers with goggles, careful siting of underground infrastructure, controls on explosives formulations and procedures, mining method selection, controls on surface temperatures and protection of equipment, careful materials selection for ventilation seals and changes to worker clothing and training.INTRODUCTIONSulphur (“Brimstone” in biblical times) is one of the world’s most important industrial feedstocks and is used in a wide range of chemical processes and industries. Until the early 20th Century, most of the world’s production of sulphur came from ‘conventional’ underground mines in Sicily (Demetra produzioni, 2006; Bellia, 2006). This was a hazardous activity. The Frasch solution mining process replaced traditional underground mining of sulphur until the late 20th Century. Most of the world’s production of elemental sulphur is now as a by-product from sour gas produced in petroleum refineries and natural gas installations (Anon, 1993). As such, there is considerable experience in understanding and managing the hazards of elemental sulphur in chemical plants and surface transport.Whilst rare, underground mines with high elemental sulphur contents (as a gangue mineral) create an unusual range of mine design and operational issues, including many ventilation-related ones. The key hazards from elemental sulphur include: primary and secondary elemental sulphur dust explosions, fires and burning (with emission of heat and sulphur dioxide or hydrogen sulphide gas), reactions with nitrates used in explosives, corrosion of steel and other metals, generation of acid water (especially at higher water temperatures), and pyrophoric reactions with naked iron (e.g., ground support, ladderways or underground fixed plant) or other metals including silver and copper (e.g., used in electrical components and equipment)."

Jan 1, 2019

By T. R. Skerry, H. P. Hudson, T. E. Warren

"ALTHOUGH coal is generally the cheapest fuel on the basis of heating value it has been at a disadvantage in competition with other fuels because means have not been available for efficient •Conversion of its thermal energy to mechanical work. Taking the •railway application •as an example, the cost of Diesel oil is about three times that of its thermal equivalent in coal, but the overall efficiency of a Diesel locomotive is about five times that of a coal-fired steam locomotive. Accordingly, the Canadian railways are replacing all coal-fired steam Locomotives, as they are retired from service, with Diesel units. This conversion in itself represents a major loss to the coal industry because the value of railway fuel is approximately 130 million dollars per year, and there are other applications in the medium power range where oil is displacing coal. There is, therefore, a strong incentive to attempt development of an efficient coal-burning engine.Coal has never been a promising fuel for reciprocating internal combustion engines because of the time required for its combustion in pulverized form . This is not less than one-tenth of a second so that the speed of such an engine would have to be very slow. There are also serious difficulties of a mechanical nature arising from the necessity for intermittent combustion and the use of close-fitting pistons."

Jan 1, 1952

By M. Abdellatif

Successful demonstration of The Mintek Thermal Magnesium Process (MTMP) was achieved in November 2004 at the pilot-scale, About 30 tons of magnesium producing recipe was smelted in the DC arc furnace over a continuous operation of 8-days, Twenty-two furnace batching-tapping operations were carried out at a feed rate of 525kg/h and a smelting temperature of 1600-1700°C, The MgO content in the produced slag was as low as 6,7%, and averaged 9,2% MgO, resulting in an overall magnesium extraction of 77%, which reached 87% during good operating periods, Magnesium vapour was extracted at a rate of 70-85kg/h and was delivered to the condenser that was operated at 680-720°C, The magnesium was captured in the condenser crucible in a liquid state, allowing its prompt tapping, More than 3500kg of crude metal were produced over 15 on-line metal tapping operations, On average, a condensation efficiency of 85% was achieved during the entire testwork, which peaked at 87% during steady operations, The quality of the crude metal was similar to, if not better than, that of the Magnetherm&apos;s crude magnesium, A pre-feasibility study has indicated that the MTMP has the potential for lower capital and operating costs as compared to the electrolytic process, and therefore Mintek and its consortium partners are exploring opportunities for a commercial production facility.

Jan 1, 2006

By J. D. Bosman, L. J. Gardner

"The Bushveld Complex is a large layered igneous intrusion, located in the northern parts of the Republic of South Africa. The complex hosts the largest known reserves of Platinum Group Metals in the world. On the western limb of the complex, mining of the Merensky economic horizon and UG2 chromitite layer has been conducted for many years by several mining companies, including Impala Platinum Limited. Over the past decade, Impala has planned a new generation of greenfield vertical shafts, commencing with comprehensive geological and geotechnical studies. As part of the geotechnical studies, numerous tests have been conducted to quantify the mechanical properties of the various near-reef rock types. These tests include point load tests conducted in the field, as well as uni-axial compressive strength, triaxial compressive strength, and Brazilian disc tensile strength tests conducted in specialist laboratories. The authors have compiled an extensive database containing a large number of tests for different rock types, ranging from felsic Anorthosite to mafic Pegmatoid. The database was analysed to quantify the mechanical properties and values for Mohr Coulomb and Hoek Brown failure criteria for each rock type typically exposed by mining. The paper will provide a data set of rock mechanical properties typically used in numerical modelling and other design processes. Using the significant number of tests available, data describing the variability of the various parameters will be included."

Jan 1, 2015

By S. Banisi, A. Haji-Zadeh, A. R. Hasankhoei, M. Maleki-Moghaddam

At the concentration plant of the Gol-E-Gohar Iron Ore Company (Iran) three 9m × 2.05m AG (Autogenous) mills (fixed speed) are used in parallel in a dry operation. The test works conducted in a scale down mill with a diameter of 1m indicated that conventionally used "deflector" type liners did not provide efficient environment for grinding. In this research, to improve the grinding efficiency, a new design using low profile end liners incorporating radial ribs of proper height was investigated. In order to determine an appropriate liner design at different operating conditions, a 100cm×10.8cm model mill was used for experimentation. The special design of model mill made it possible to increase the radial ribs height in steps of 6mm up to 18.5mm. The transparent end of the mill enabled accurate trajectory determination by image analysis. The results indicated that the new lower height profile deflectors and 15.5mm-height (14.5cm in industrial scale) radial ribs improved the mill performance while avoiding excessive pressure drop across the mill and wear on the liner. The image analysis showed that the use of new liners increased the distribution of coarse particles across the mill cross section from 28% to 35%. A new liner design was proposed by decreasing the number of liners in each slice from 5 to 4 pieces. The thickness of the inner head liners reduced from 45cm to 30cm and the outer deflector liners replaced by radial ribs. The distance between the feed and discharge inner head liners increased from the original 115cm to 145cm which increased the effective length of the mill by 26%. The new design reduced the weight and volume of end liners by 9% and 23%, respectively. It was predicted that the new liners design increases the mill throughput by 10% and reduces the metal consumption by 20%.

Jan 1, 2016

By Eldon L. Brown

Location and History The Sherritt Gordon property is located in northwestern Manitoba, about 100 miles north of The Pas and 40 miles northeast of Flin Flon. It is connected with the Manitoba Northern railway, which runs from The Pas to Flin Flon by a branch line, 42 miles in length. The location of the property is shown on the sketch-map, Figure 2. The ore deposit was first discovered by Philip Sherlett, a Cree Indian, in 1922. In 1924 Sherlett&apos;s claims lapsed and the ground was re-staked by Carl Sherritt and Dick Madole, and was optioned by them to J. P. Gordon in the summer of 1925. Gordon re-optioned the property successively to three well-known mining groups, one of which did some surface trenching .and put down 28 shallow diamond-drill holes before dropping their option. In the latter part of 1927, a Company known as Sherritt Gordon Mines, Limited, was formed to take over the property, and preparations were made for systematic development work. Preliminary Development In order to fill-in gaps left by the original drilling, a light diamond-drill outfit was flown-in to the property from the Hudson Bay railway in the early fall of 1927. Ten shallow holes were put down before freeze-up .and a considerable amount of surface trenching was completed. Based on the results of the surface trenching and the shallow diamond-drilling, an extensive development campaign was outlined. A winter road, 90 miles in length, was cut from mileage 55 on the Hudson Bay railway, and during the winter of 1927-28 a total of 2,600 tons of freight was hauled-in to the property. This freight included four complete diamond-drill outfits, two complete mining plants, building material for two sets of camps, and supplies for one year&apos;s operations, including 105,000 gallons of fuel-oil for Diesel engines.

Jan 1, 1933

By L. E. Djingheuzian

ANON-CATARACTING (N-C) ball mill is so operated that the balls are not thrown in-ward at the top of their paths. The result is to maintain, in the mill, a quiescent pool in which classification will occur at a limiting size corresponding to the pulp density. N-C operation is produced by effecting proper relationship among mill speed, ball diameter, volume of ball load, and pulp density. Such operation is typified by the primary ball-mill operation of the Tennessee Copper Company, Copper-hill, Tenn., and the Cleveland Cliff Iron Company, near Ishpeming, Mich.

Jan 1, 1958