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By C R. Crook

A brief outline of production methods and processes is given to show how maintenance fits into the picture at this plant. The work force, and the tools needed to carry out this function, are then described. Preventive maintenance practices, scheduled annual shutdowns and routine check-downs are explained, especially as related to planning and to the materials and labour involved for a mini-mum downtime. A brief explanation of the materials, sup-plies and spare parts program, as well as the part played by the Stores Department in conjunction with the Maintenance Department, is given. Cost control and equipment expenditure indicators are explained. Some specific examples of maintenance jobs are described in order to show the flexibility of the program. S HERRITT GORDON Mines Limited has been in continuous production, except for the planned downtimes needed for expansion tie-ins, or the annual shutdown check-over periods, since the first shipment of nickel on a commercial basis in July of 1954.

Jan 1, 1964

By J. Mirza, E. Nicol, J. Lipkowski

Gold passivation in thiosulfate leaching media is a major barrier to its implementation. Addition of Cu (II) into the leaching solution has shown to aid in gold dissolution, but the mechanism by which it acts, and its role in the passive layer, remains unknown. Surface Enhanced Raman Spectroscopy (SERS), in tandem with linear sweep voltammetry, were employed to determine the dependence of leaching currents on mass transport and for fingerprint identification of sulfur species on the surface of gold. SERS leaching experiments were performed using gold nanorod electrodes that showed increased stability compared to other SERS active surfaces.

Jan 1, 2011

By Liguang Wang

The froth phase in flotation has received much less attention than the pulp phase despite the fact that froth stability plays an important role in determining flotation performance. Froth stability is largely determined by the stability of thin foam films, which in turn has a strong correlation with the critical rupture thickness (Hcr) of the films. In the present work, a new approach to predicting the Hcr values of thin foam films in flotation froth phase was proposed and examined. The Hcr values were calculated using an advanced capillary wave model with input parameters being surface tension, film radius, capillary suction pressure, and intersurface force. The intersurface force was estimated by using the Stefan-Reynolds lubrication approximation to fit the measured thinning rates of single foam films formed in a Scheludko ring cell, where the film radii were less than 50 microns and were kept constant during the film-thinning process. A comparison between the predicted and experimental Hcr values was made for the films with the use of sodium chloride as background electrolyte and in the presence of various frothing reagents such as methyl isobutyl carbinol (MIBC), polypropylene glycol with an average molecular weight of 400 (PPG400), and sodium dodecyl sulphate (SDS), at different concentrations and film radii. It was found that the model correctly predicted the trends of Hcr-versus-concentration and Hcr-versus-film radius curves. Moreover, the predicted Hcr values matched well with the experimental ones of the foam films containing either SDS or PPG400. For the foam films containing MIBC, however, the model overpredicted the Hcr values. The reason for this discrepancy was discussed.

Jan 1, 2016

By Roger J. Goodman

"Major industrial restructuring, which started to manifest itself in the mature economies of the Western World and Japan in the 1970s, will accelerate in the 1980s and 1990s. Conventional heavy manufacturing industries will continue to lose ground to lighter processing/assembly operations and the new wave of high technology, information and service sectors. The decline in heavy manufacturing has severely impacted on the steel industries of Western Europe, the U.S.A . and Japan.World trade in metallurgical coal has shifted correspondingly, with declining demand in the mature developed countries being only partially offset by large increases in the steel intensity of the newly-industrialized countries (NICs) of the Far East, Latin America and, to a more limited extent, the Middle East and Africa. These trends will be accentuated in future years with direct implications for the distribution of metallurgical coal trade. This paper discusses, in quantitative terms, such changes in the 1980s and 1990s, and examines the implications for, and impacts on, Canadian metallurgical coal exporters.IntroductionThe twenty-year period from the early 1950 s to the early 1970s was characterized by inexorable growth in consumer demand and industrial expansion in most of the advanced countries of the western world. Long- term forecasting during this period typically used linear extrapolation techniques which , despite their simplicity, invariably ended up predicting future demand and production level s with uncanny accuracy. Times have changed!The last decade has been characterized by a n abysmal failure of our economies to respond to simple long-term, linear growth patterns. We appear to have entered a new world in transition, where we can observe a wave of dying or sunset industries reluctantly being submerged by a wave of emerging or sunrise industries.This paper is aimed a t examining the evidence for long-term industrial restructuring trend s. For want of a better word, these so -called, megatrends are then used to predict future demand level s and spatial distribution of steel development and , hence, metallurgical coal trade. It is tempting to correlate the decline in economic activity in the western world with the first Organization of Petroleum Exporting Countries' (OPEC) crisis of 1973. This crisis was probably no more than the straw that broke the camel's back, as the megatrends and embryo s of major industrial restructuring were already evident. Today these megatrends are merely more apparent and transparent than they were ten years ago.While the concept of industrial restructuring is the new economic buzz word, the process was at work, to a lesser degree even throughout the period of strong economic growth of the post-Second World War boom. Many people still remain convinced that our present-day sluggish economy is just part o f the typical , though rather more prolonged, recessionary cycle. Yet, we have always been part of a dynamic economic system and industry throughout history has been the subject of a continuous process of evolution, restructuring and reconstitution . Now the time is ripe to examine the evidence for such restructuring in order to develop coherent policies of adjustment in this transition from one industrial regime to another."

Jan 1, 1985

By Joseph Bradley

THROUGHOUT this article, minerals used in the paint industry are designated 'pigments'. They may be classified in two groups: (1) Pigments which are used in the state in which they occur in nature, requiring only mechanical preparation. (2) Pigments which require heating or chemical treatment before use, in order to obtain from them a product of the desired quality or shade of colour. They may be further classified according to colour, as follows: White Pigments .-These include calcium carbonate (chalk, marble), gypsum and alabaster, kaolin-or china-clay, and magnesia. However, the white pigments most extensively used are compounds prepared chemically from minerals containing lead, zinc, titanium, and antimony. The white pigments are of particular importance because, not only are they used by themselves, but they also serve as adjuncts to other colours for the production of special shades. Yellow Pigments.-These are mainly naturally occurring ferric hydroxides, as limonite and bog iron ore, or similar. compounds prepared artificially. Brown Pigments .-Pigments of this group are distinguished for their beauty and depth of colour, and many of them are used in the finest of paintings. Familiar names are sienna, umber, and Vandyke brown. They are for the most part ferric hydroxides, containing varying amounts of water; but the group also includes a manganese brown, which consists chiefly of a mixture of oxide and hydroxide of manganese. Red Pigments.-Chief among this group is ferric oxide, known under various trade-names, such as Canadian red, Persian red, etc., and also the much prized and somewhat rare vermilion. The pigment used is either naturally occurring hematite, de-hydrated limonite, or artificially produced red ferric oxide.

Jan 1, 1937

By P. Morissette

Passive monitoring of support performance during rockbursts was conducted at three deep underground mines. A comprehensive database was constructed of 172 seismic events and the associated damage to support systems at 266 mine locations from January 2000 to September 2012. The majority of pertinent information was obtained through seismic system records and on-site field assessments. This work assesses the quality of collected information and evaluates the dynamic-load demand on support systems in seismically active mines.

Aug 1, 2013

By Randy McMeekin, Chris Twigge-Molecey, J. Peter Blake

The project implementation phase, FEL4, is generally a complex undertaking. The project has been approved for construction and the capital has been allocated. At this point the project team comes under significant pressure to meet the safety, schedule, cost, and start-up committments. For the design team the principal tasks are to finalize detailed design, complete procurement, and issue construction contracts. Design activities must be closely coordinated with equipment and material procurement. A clear engineering plan should be based on well-defined work packages to meet construction, commissioning, and startup requirements. A range of review processes by discipline, area, and third parties assure quality. Constructability, safety, and hazard reviews are performed throughout the design process. Three-dimensional models that incorporate extensive databases help to maximize efficiency and minimize errors. Well-managed projects have a clearly accountable design team, rigorous change control processes, and well-defined workflows. Key individuals from the design team participate in commissioning, operator training, and startup.

Jan 1, 2015

By D. G. Sinclair

IN surveying the changes that have taken place in the mining industry of Ontario in the past ten years, the striking growth of the gold mining industry first attracts attention. In 1925 there were only twelve regularly producing gold mines in the Province, six of which were located in the Porcupine area, four at Kirkland Lake, and one each at Larder Lake and Boston Creek. In contrast with this, the year that has just closed (1935) has seen production on a steady basis from forty mines, with what may be termed spasmodic production from twelve other properties. This so-called spasmodic production is, however, responsible for the recovery of gold to an estimated value of between $75,000 and $100,000 during the year. Further illustrating the expansion in the gold mining group is the activity in the exploration and development of properties. In 1925, mining operations were conducted at 29 properties which had not reached production, while in 1935 work of this nature was carried on at 87 such properties. It is of interest to note that of the six properties listed as producers in Porcupine ten years ago, five are still producing at rates considerably in excess of the tonnages handled at that time. In fact, the estimated tonnage treated at these mines in 1935 exceeds the 1925 tonnage by approximately half a million tons. In Kirkland Lake, the figures are still more striking. The four mines in production in that camp in 1925 milled 346,584 tons, producing bullion to the value of $5,132,128, while in 1935 these same mines treated approximately 1,643,000 tons, with a recovery of roughly $29,300,000. While Porcupine and Kirkland Lake remain the great gold-producing camps of the Province, the growing importance of the newer areas is readily appreciated when we consider that in 1935 the mills of these areas treated over 1,000,000 tons of ore for a production in excess of $7,500,000. Pro-duction from these newer districts first became of importance in 1930 with the commencement of recovery at the Howey mine, in Red Lake, and the Minto, in Michipicoten. Since 1930, eighteen new gold mills have gone into production in the Red Lake, Little Long Lac-Beardmore, Pickle Crow, Sturgeon Lake, Michipicoten, Sudbury, and Matachewan areas. In respect to silver mining, the period under review has seen a considerable slackening of activity, due to a generally unstable and depreciated price for the product and to the exhaustion of ore reserves in the mines.

Jan 1, 1936

By J. P. Morgan, D. B. Stewart

"AbstractLoad-haul-dump machines equipped with. a torque converter and hydraulic pumps have been field tested by means of an engine monitoring instrumentation package. It was found that owing to parasitic losses in the ancillaries and drivetrain, maximum available useable pourer may peak at less than full engine speed. Simple reduction of engine speed may save 15 to 25 percent on fuel consumption, with no significant loss of available power. On some machines, speed reduction will require modification of the torque converter . The cost of this modification, when necessary , would be offset by reductions in exhaust emissions, ventilation requirements, fuel consumption , heat, noise and hydraulic system maintenance, and by increased life of rotating components and filters and machine availability.IntroductionTHE CANADIAN EXPLOSIVES ATMOSPHERES LABORATORY, in conjunction with Deutz Canada Limited, has designed, constructed and field tested a portable instrumentation package. This package monitors diesel engine performance in underground mining machinery by continuously recording engine speed and volumetric fuel delivery. During tests designed to determine the engine load and speed conditions for the various segments which constitute actual underground operation of a Deutz F6L 714-powered 4-yard load-haul-dump machine, it was discovered that an unexpectedly large percentage of the engine power was required to overcome the ancillaries and drivetrain drag (1). That this large component of engine power is functionally related to engine speed rather than the operator's needs was verified by repeat tests of the used 4-yard machine and by testing of a new 5-yard machine powered by a Deutz F 8L 714."

Jan 1, 1977

By R. St. C., G. E. Morris, M. Zbik, Smart

Effective flocculation and dewatering of slurry streams containing clays (particularly kaolin and smectites which are often <200nm in lateral dimension) is becoming increasingly urgent. Release of water (often >75 wt%), for recycle and reduced make-up water consumption, from slurries in tailings streams and dam beds is usually slow and incomplete. Changes in settling rates and solids density of tailings containing clays can be achieved in practice by changes in pH, dissolved cations and flocculant additions. To achieve fast separation of clays from water and minimization of retained water, individual particles need to be bound in the initial stages of thickening into large, high-density aggregates, which may sediment more rapidly with lower intra-aggregate water content. Quantitative STIMAN (STructural IMage ANalysis) cryo-SEM imaging, shows that the structure of aggregates formed before flocculant addition has a determinative effect on these outcomes. Without flocculant addition, 4 stages occur in the mechanism of primary dewatering of kaolinite: initially separate particles and aggregates are dispersed (<0.3GP, where GP is the gel point); a partially-gelled chain network then forms linking particles edge-edge (EE) still well below the OP but remains largely suspended; after an induction time, this network structure rearranges from EE to face-face (FF) contacts densifying, compacting and dewatering the aggregates with settling rates well above Stoke&apos;s Law estimates for >20µm particles or aggregates; the GP is rapidly reached during settling producing a network spanning the vessel with compressive strength. This sponge-like structure with EE oriented particles limits slurry dewatering because the steric effect in the resulting partially-gelled structure is much more dominant than the electrostatic effects predicted by DLVO theory. Van der Waal&apos;s forces at very close distances, as particles slide across each other, may be responsible for the EE to FF change in structure. In this way, the previously extended network contracts, and when the solid volume fraction is low, the continuous network breaks apart forming aggregates and aggregate associations as flocs which arc able to freely settle. These densified aggregates settle at increased rate, give lower bed density and retain less water after drainage. With flocculant addition, the internal structure and networking of the pre-aggregates is largely preserved but they are rapidly and effectively bound together by the bridging action of the flocculant(s). The STIMAN analysis shows that there is a inverse correlation of intra-aggregate porosity (and void permeability) with Darcian permeability (and extent of dewatering) whereas there is a strong positive correlation of Darcian inter-aggregate permeability with settling and primary dewatering rate.

Jan 1, 2004

By Michael Boyle, John Zeni

"The Blind shaft boring method is a mechanised process of excavating large diameter vertical shafts downward from the surface. It is a rotary drilling technique eliminating any requirement for personnel to enter the shaft or access underground workings during drilling and lining phases. Excavated material is delivered to surface carried by a flow of circulating fluid through the centre of drill rods. The drill assembly is suspended from a large A-frame rig and powerful winch at ground level providing vertical thrust to a hard rock cutter head. INTRODUCTION The Southern Coalfields Ventilation Shaft was constructed at a mine, 45 km north-west of Wollongong. The 5 m finished diameter (6.2 m drilled) shaft reaches a final drilled depth of 517 m, the deepest, fully lined blind bored vent shaft to date in Australia. Operated by a mining company in the Southern Coalfields, the expanding mine required a new ventilation shaft and associated surface infrastructure to service future operations. An assessment of future ventilation requirements for the coal seam operations identified a need to improve the capacity and reliability of the existing underground ventilation system in order to ensure a safe and efficient underground working environment. Installation of the new upcast ventilation shaft was determined to be the most cost effective and reliable solution to provide adequate ventilation for underground operations. The completed shaft is smooth and fully lined with steel/concrete composite liners that are hydrostatically sealed. The shaft lining is designed to meet the mine ventilation requirements for a service life of 20 years. The shaft intersects the top of the working section of the coal seam at approximately 513 m of depth. This includes the shaft collar depth and shaft bottom profiled intake section.PROJECT METHODOLOGY AND INDUSTRY BEST PRACTICE The shaft was drilled using the blind bore method, an innovative construction technique and an alternative to the traditional methods of sinking deep and large diameter shafts, such as raise boring and conventional drill and blast shaft sinking. The blind bore method allows the shaft to be drilled from the surface down without anyone having to enter the shaft or the mine during the construction process. This is by far the safest method of shaft construction and is especially suitable for difficult ground conditions where there may be unstable or water-charged strata. As this method involves drilling from the surface downward, shafts can be completed ahead of the underground mine development. Thus, allowing underground operations to focus on development and production without the conflicts of managing ventilation priority for underground contractors and mucking out spoil from excavation workings."

Jan 1, 2019

By C. Harold Riches

This article is directed co a commentary on the patent system in its relation to the public interest. As man gained supremacy over his environment, he could devote progressively increasing portions o his time to improving his standards of living. In the history of the human race, we have advanced from the hollowed floating log to the modern steamship of the present age; from the sickle and flail to the reaper and combine; from the trumpet and drum as a means of communication co the telegraph, telephone, and radio; from the horse and ox cart to the automobile, truck, aeroplane, and train; and so on ad infinitum through the list of inventions on which are based the industrial and political economies and standards of living we enjoy today. It has also been a long road from the day of the alchemist and his closely guarded secrets to the era of the patent system and its storehouses of knowledge open to the world. The alchemist and the craft and merchant guilds closely guarded their secrets. In fact, they largely opposed innovations on the grounds that they might injure profits and restrict employment. In these days of unrest, with great clamour out of doors for radical changes in our political and industrial economies, it may not be untimely to examine one of the keystones which support the economic structure we know as the free enterprise system, the system which is predicated upon the right of the individual to own property. Many, through impractical idealism, ignorance, confused thinking, or blind political prejudice, advocate the substitution of ownership by the State ? for the right of ownership by the individual. As civilization has advanced to the high standards of living we enjoy today through the efforts of a comparatively few inventors, the patent system which has provided the incentive that created the inventions on which our industries and our employment are based is fully understood and appreciated by a comparatively small percentage of our people. As a result, the patent system, as a keystone in our free enterprise economy, is an apt target for destructive criticism, with the thought, possibly, that by eliminating or drastically restricting the several rights to individual ownership one by one, ownership by the State will progressively replace ownership by the individual.

Jan 1, 1949

By Charles S. Ney

"ZINC-LEAD REPLACEMENT deposits straddle the steep-sided valley of Kicking Horse River at a point three miles east of Field, B.c., in Yoho National Park. The Monarch orebodies extend into Mt. Stephen on the south side of the valley, and outcrop at two points, 1,000 and 1,200 feet above the valley floor. The Kicking Horse deposits are in Mt. Field, on the north side of the valley, and they outcrop 200 feet lower.The East Monarch outcrop is said to have been discovered in 1884 during construction of the Canadian Pacific Railway. The larger West Monarch outcrop, 700 feet west of the original discovery, was not reached till 1917 because of its nearly inaccessible location on the cliff face.The Kicking Horse mine was staked in 1906. Little development was done for several decades, and mining was not commenced till 1935.At the East Monarch, mining was commenced soon after location, and several thousand tons of ore were shipped prior to 1912. At this time a gravity concentrator was installed. This was operated till 1924, and a total of 42,000 tons of ore were mined, including about 10,000 tons from the West Monarch. The period from 1928 to 1935 featured flotation milling and the mining of 265,000 tons of ore, mostly from the West Monarch orebody. Intensive exploratory development was carried out in both Monarch and Kicking Horse from 1935 to 1946. Production from both mines in this period totalled 380,000 tons. From 1947 to the time of closure in 1952, considerable new ore was found in both mines and 185,000 tons were milled. Immediate possibilities for finding ore in the Monarch were considered exhausted. Kicking Horse orebodies are known to persist with a low grade of zinc. Total production from the two mines amounts to 842,500 tons grading approximately 7 per cent lead, 10 per cent zinc, and 1.2 ounces per ton silver."

Jan 1, 1949

By Henry C. Knight

A number of improvements in the techniques of budgetary control have been developed in the 1970&apos;s. The most significant of these is zero-base budgeting. This procedure is a marked improvement, because it overcomes some of the key weaknesses inherent in most traditional approaches to budgeting. It incorporates techniques and disciplines which improve the quality of both the budgeting effort itself and the documents that most senior managers will need to evaluate. The end result is a budget that establishes and improves cost effectiveness. This budget is based on resource allocations using cost-benefit criteria and on a system of prioritization for making funding choices. Zero-base budgeting is applied only to costs and expenses that are not conducive to control using industrial engineered standards. Therefore, the benefits attributed to zero-base budgeting will only hold true for administrative, selling, exploration, safety, fire protection and overhead, and other indirect types of costs and expenses. It is in this context that the question of its attractiveness for the mining industry is dealt with.

Jan 1, 1978

By P. Chu, J. A. Finch

The formation of small bubbles in flotation is usually accomplished by the use of frothers, or sometimes is due to the presence of inorganic salts in the process water. The effective mechanism associated with the presence of these solutes is generally considered to be coalescence inhibition. However, recent work has demonstrated that the presence of frothers and salts also reduces the size of bubble at the initial formation stage. In this paper we adapt the same experimental setup to investigate the time that it takes for a bubble to form; for a known system power input, the energy to form a bubble can then be estimated from the time. The hypothesis is that the presence of frother and salt will reduce the time for a bubble to form, which can be interpreted as an added energy component being derived from the solute. Testing different types and concentrations of frothers and salts, the hypothesis is supported: the mechanical energy required to form a bubble decreases by about 10% in the presence of these solutes.

Jan 1, 2015

The teaching of geophysics in Canada at the present time presents a variety of approaches to the subject, and the different paths adopted imply, in turn, an uncertainty in the minds of some educators as to the role this science is to play in the future progress of geology, and a hesitancy to commit themselves to foster its development. The pedagogical attitudes vary from a whole-hearted acknowledgment that the science of geophysics is fundamental to the understanding of terrestrial phenomena (including, of course, geological processes) to a hesitant immersion of the toe to test the water&apos;s temperature (which is, of course, essentially a geophysical experiment) before deciding whether or not the time is ripe for total immersion. The present discussion has been organized in the hope that it will help to clarify the roads to geophysics and assist educators in making a more understanding choice of the best paths for them to follow, according to their particular requirements and objectives. Before proceeding further, however, it is necessary to define the term geophysics and circumscribe the field it covers. In the first place, it should be emphasized that geophysics is NOT confined to the art of geophysical prospecting. The popularization of geophysics has unfortunately engendered a general misconception of the word, and consequently a tendency to ignore the wider meaning of the term. Etymologically, geophysics means the physics of the earth. It is so understood by the International Union of Geodesy and Geophysics and the various geophysical societies which adhere thereto. To them, geophysical prospecting is but a very small field indeed, which they consider had best be left to engineering and prospecting organizations.

Jan 1, 1951

By Christopher Boys

"Abstract -Many water inflows in Saskatchewan potash mines are linked to salt anomalies. Potash ore and three anomalies in the PCS Cory potash mine in the Patience Lake Member of the Prairie Evaporite Formation were studied to understand the processes involved in their formation. Another goal was to find geological indicators of the proximity of anomalies. A geological model that relates the potash to the salt anomalies has been developed.Up to five post-burial facies may be recognized . These range from carbonate-mud collapse breccias to bedded sylvinite, and probably result from post-burial leaching. ln this model, the same fluids that caused widespread recrystallization and possibly enrichment of the potash salts, started by dis­ solving huge cavities in the evaporites . The effects of the leaching were highly variable, indicated by selectively preserved delicate laminae and chevron textures, to deformed and totally dissolved salt beds . ln at least two major events, Late Devonian and Cretaceous, collapse structures may have acted as conduits for overlying formation waters to cause pervasive leaching and recrystallization of the Prairie Evaporite Formation .Geological indicators of the proximity of an anomaly may include: a change in Insoluble seam color from greenish-gray to mottled brown and greenish-gray, unusual local increases in ore grade, large patches (e.g., >200 cm2) of sylvite-poor potash crosscutting units near the top of the ore zone, and drops in topography >10 m of the marker seams. Anhydrite was more common in an anomaly than in ore. The local abundance of anhydrite in ore may indicate the proximity of some salt anomalies.Once an anomaly has been encountered, indicators of a major collapse feature may include: stretched clay seams, folded beds, small collapse features (1 m to 20 m), numerous washouts, or split clay seams with injected salt. Any number, or none, of these indicators may be found close to a major collapse feature."

Jan 1, 1993

By J. Zachwieja

As part of a general review on study of surfactant blinding agents to improve gold recovery during cyanide leaching of carbonaceous gold ores, processes of CIL and RIL leaching using surfactants were investigated. When refractory ores were treated by surfactants, CIL and RIL leaching processes yielded significant improvement on gold recovery. This paper will discuss and compare the laboratory results from two different leaching processes on preg-robbing ores, as well as, illustrate the difference of potential fouling of the blinding agents on activated carbon and resins.

Jan 1, 2015

By G. M. Ritcey, K. E. Haque

"Laboratory-scale sulphuric acid leach tests were conducted on Elliot Lake and Rabbit Lake ores in the presence of various oxidants, namely: Fe2(SO4)3, CI2, H2O2, NaClO3, MnO2, H2SO5, HNO3, Oxon e, K2Cr2O7, KMnO4, O3 and O2. Uranium extraction is significantly accelerated when an oxidant is present in the leach slurry. Uranium extraction of 96-99% can be achieved by maintaining the oxidation potential of the leach slurry in the range of400 to 500 m V (S.H.E.). A rough cost comparison of all the oxidant s indicates that the use of Fe2(SO4)3, 02, O3, C12, HNO3 or MnO2 is far less expensive than NaClO3 and the uranium extraction rates are similar to or better than with NaCIO3. For uranium extraction, it is concluded that gaseous oxygen (i.e., air or oxygen) would be the most effective and economical oxidant for the 24- to 36-hour leach of Elliot Lake ore; whereas for the 8- to I2-hour leach of Rabbit Lake ore, a strong chemical oxidant (e.g. NaCIO3, H202, 03, K2Cr2O7, H2SO5 or HNO3) would be a logical choice.IntroductionThe common practice for the treatment of uranium o res is leaching with sulphuric acid or with a carbonate-bicarbonate mixture. Generally, the latter process is ad opted when an excess (> 18%) of acid-consuming components (e.g., carbonate) is present in the ore. Irrespective of the nature of the leachant, the addition of an oxidant to the leach mixture is necessary to obtain a high uranium extraction.The maximum extraction of uranium can only take place when all the uranium is in the highest oxidation state (i.e.,U +6-uranic ion) . Because a certain percentage of uranium present in the ore is invariably in the lower oxidation state (i.e.,U+4-uranous ion) , the addition of an oxidant to the leach slurry is necessary to oxidize uranous ion to the uranic state."

Jan 1, 1982

By P. W. Billwiller

Abstract The Britannia Mining and Smelting Company, Limited, have replaced diamond drills with percussion drills and tungsten: carbide bits for most of their blast hole drilling operations and have thereby reduced ore breaking costs. Two-inch Carset bits .are used, with one-inch hexagonal Atlas Chippewa alloy steel in 3-foot .and 6-foot lengths. Locally made couplings of Atlas SPS 245 alloy steel connect the rods. The machines used are 31½-inch automatic leyners with lugged or anvil block chucks. For drilling holes below the horizontal, the lugged machines with special adapter rods made from 114- inch solid round Atlas SPS 245 are required. These rods are lugged at one end and a water hole is drilled for six inches into the other end. Over this rod is placed a water swivel which permits the water or air to be sent directly into the steel. A decreased cost per foot, increased footage per shift, and the use of standard equipment and crews are some of the main advantages of tungsten carbide drilling over diamond drilling. Introduction Long-hole drilling with percussion drills and sectional steel was introduced in several American mines some twenty-five years ago. It did not prove very successful, however, because the rapid gauge loss in steel bits necessitated the use of very large starter bits. This in turn rapidly fatigued the straight carbon-steel then in use, made it difficult to maintain the couplings, and resulted in a slow drilling rate. The introduction of the tungsten carbide insert bit and alloy drill still has changed this picture and opened real possibilities for the application of percussion drills to blast-hole drilling. If this type of bit had been perfected ten years ago, much of the research work and experimenting done to apply diamond drills to ore breaking would have gone toward developing the application of the tungsten carbide bit to this problem.

Jan 1, 1950