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By J. C. Underwood

"The wear performance of grinding balls under conditions of impact and abrasion is affected by their chemical composition and structure. The selection of appropriate analyses and heat treatments that will provide both abrasion and impact resistance takes into account the effects of certain elements on structure and harden-ability, as well as the over-all effect of composition and hardness penetration on the residual stress pattern developed through heat treatment. Direct quenching from forging temperatures substantially increases hardenability over that obtained in reheat-quench practices, and can be done without undue risk of damage to the ball provided that the harden-ability bears the correct relationship to ball diameter.Average volumetric hardness and percent hardened volume are convenient parameters for quantitatively expressing the response to heat treatment and indicating anticipated wear properties. A number of factors which can lead to reduced wear life as a result of material or processing problems are reviewed and illustrated."

Jan 1, 1959

By Peter Hayes, Evgueni Jak, Taufiq Hidayat, David Grimsey, Denis Shishin

"An integrated nickel flash smelter is operated with Peirce-Smith converters at the Kalgoorlie Nickel Smelter. To improve the partitioning of arsenic between slag waste and matte product, an option to modify the slag–matte chemistry by addition of CaO was analysed. A combination of plant sample analysis, high-temperature laboratory experiments and thermodynamic modeling was carried out to evaluate the process options. The high-temperature experiments involved the re-equilibration of industrial matte-slag samples at 1225 °C and P(SO2) = 0.12 atm, rapid quenching in water, and direct measurement of phase compositions using electron probe X-ray microanalysis (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LAICPMS). A private thermodynamic database for nickel sulfide smelting and converting was used together with the FactSage thermochemical software package to assist in the analysis of the distribution of elements between slag and matte as a function of CaO addition. The thermodynamic predictions combined with experimental data obtained in this study can be used to characterise the effect of CaO fluxing on the slag–matte thermochemistry during the nickel sulfide converting.INTRODUCTION At the Kalgoorlie Nickel Smelter (KNS), nickel sulfide concentrate is processed in an Outotec-type flash furnace to produce nickel matte containing +47 wt% Ni. Separation of nickel matte and waste slag from the flash smelting is enhanced through settling in the electric arc -heated zone attached to the flash furnace. The flash furnace matte is further processed in a Peirce-Smith converter to produce Ni-rich matte containing +66 wt% Ni (Crundwell, Moats, Ramachandran, Robinson, & Davenport, 2011). Iron silicate-based slag is used in the converting process at KNS. Most of the arsenic is contained in the final matte and very little of the arsenic partitions into the slag. Previous work by Font et al (Font, Hino, & Itagaki, 2003) shows that the distribution ratio of arsenic between calcium ferrite slag and nickel-matte (LAsslag/matte) is significantly higher than that between iron silicate slag and nickel-matte, where LAsslag/matte = (wt pct As in slag)/{wt pct As in matte} (1)"

Jan 1, 2017

By M. Wu, G. Plascencia, A. E. M. Warner, A. Vahed, T. A. Utigard

Nickel oxide granules formed by pyrohydrolysis of a chloride solution, were reduced in hydrogen. Below 400 °C, an incubation period was observed, followed by very slow reduction. In the temperature range from 400 to 600 °C, the rate of reduction increased with increasing temperature and increasing hydrogen pressure. Microscopic analysis showed that in this temperature range the reaction followed the shrinking core model. Above 600 °C, the reduction rate decreased noticeably before suddenly becoming very fast at and above 950 °C. Microscopy showed inner bands of metallization inside the outer metallic rim, indicating partial blockage of the interface between the reacted and un-reacted NiO core. At these temperatures, particle agglomeration and sintering were also found to take place. Surface segregation of sulphur may account for the slow down in reduction rate above 600 °C. From an industrial point of view, reduction should be carried out from 550 to 600 °C with as high a concentration of hydrogen as possible. If sintering and agglomeration are not of any concerns, reduction can be carried extremely fast at about 1000 °C.

Jan 1, 2005

By E. Eccleston, E. Gardner, F. Letarte, R. Schonewille

"In 2005, after nearly a decade of process development and feasibility work, the commercialization of the Falconbridge Nickel Smelting Technology (NST) began in earnest with the design and construction of a grassroots ferronickel plant at Koniambo Nickel in New Caledonia. The NST process was developed as an alternative to the conventional Rotary Kiln-Electric Furnace (RKEF) process for production of ferronickel from saprolitic nickel laterite ores. The NST process promised environmental and energy efficiency advantages over the conventional route. A key step of the NST process involves fluidized bed pre-reduction of calcined laterite ore using direct injection of pulverized coal as the reductant. Two parallel fluidized bed reduction roasters (FBRs) were installed at Koniambo Nickel, each designed for a maximum capacity of 4,200 MTPD of calcined nickel laterite ore. This paper describes the process development and scale-up of the fluidized bed pre-reduction process, the design challenges associated with the prototype commercial units, and the current status of the FBR operation at Konaimbo.INTRODUCTION In the mid-1990s, Falconbridge began to develop a new flowsheet for production of ferronickel from nickel laterite ores. The process that developed came to be known as the Falconbridge Nickel Smelting Technology (NST). The flowsheet, which is particularly appropriate for saprolitic ores, involves several major unit operations, including: drying in a hammer mill-flash dryer, calcination and preheating in a flash calciner, pre-reduction in a fluidized bed reactor, and smelting in a DC arc furnace to produce the ferronickel product. This paper focuses on the fluidized bed pre-reduction step of the process and provides an overview of the process chemistry, laboratory and pilot plant development work, scale-up and commercialization of the pre-reduction step, and the results obtained in the prototype commercial units."

Jan 1, 2017

By Fernando Romero Lage

"Crushing and screening theory and application has remained fairly consistent in the last 50 years. The application of such equipment is guided by varied formulaic conventions and rules that due to the entropic nature of the process, remains more an art than a science. The variability of conditions creates an environment in which trial and error becomes the principal means of process balance and control. This paper illustrates some of the theories behind the process, plus other assumptions, postulates, myths and misconceptions that exist within the crushing and screening industry.INTRODUCTIONContinuous material balance calculations are habitually performed in the design of new comminution circuits as well as in the valuation of existing circuits. A continuous material balance calculation is one in which the input rate of material is equal to the output rate for each unit functioning in the circuit. At continuous analysis, there is no accumulation or losses of material within the system, as it is when performing a discrete event analysis.In order to produce viable and manageable mine-to-mill material, whether it is ready to leach or ready to mill, we must reduce the material in a series of stages. The power demand increases as the material size decreases, as it is when folding a piece of paper successively. As with the paper, there is a crushing size limitation that is a consequence of the mineral properties such as work index, moisture, viscoelasticity, etc. Comprehensive knowledge of crushing plants in both the aggregate and the mining industries show that, after three stages of crushing, a particle size distribution originating from a blasted deposit can be reduced from an nominal maximum size of 500 mm to a nominal maximum size of 12 mm. if the last stage of crushing is set in closed circuit, the screen openings will be able to yield a smaller top size.Achieving steady and continuous material balance poses major difficulties as crusher lose their settings, screens blind or peg, and material characteristics change geographically or seasonally. Overloading conditions in crushers and screens are nothing but counterproductive, and the net losses of an unbalanced circuit can be overlooked when mining operators are paying a lot more attention to the evermore complex systems downstream.It is not simply the crushing of the mineral but achieving the right size for the downstream milling process that will yield the maximum amount of energy savings."

Jan 1, 2010

By Real Daigneault, François Robert, J. Paul Golightly, Jean-Yves Cloutier, Jayanta Guha, Pierre Pilote

"The Casa-Berardi East, Center and West deposits, located in the Archean Abitibi, Sub province, are hosted by volcanic and sedimentary units of varying compositions, less than300 m from the Casa-Berardi fault (CBF). The CBF, a brittle structure, represents an increment in the structural evolution of a regional-scale deformation zone showing ductile-brittle behavior known as the Casa-Berardi deformation zone (CBDZ). The CBDZ is characterized by a mylonitic Sc1 foliation which is folded a.n4 deformed by a later sczfoliation in high strain zones.Four generations of quartz vein and fracture systems have been recognized within the Casa-Berardi deposits. Most economic gold mineralization, occurring in the second generation system, is found within high strain zones. This system hosts three types of mineralized structures: (1) banded quartz veins; (2) swarms of veins and mineralized host rocks; and (3) disseminated sulphides along fractures. An early carbonate hydrothermal alteration zone (pre- to syntectonic) surrounds the deposits. Alteration associated with gold mineralization is contemporaneous to late ( syn- to post-tectonic) relative to the development of progressive deformation in the CBDZ. The geological characteristics and paragenesis of the four quartz vein and fracture systems developed as an integral part of the geodynamic evolution of the Casa-Berardi deformation zone."

Jan 1, 1990

By Christoph Miller

About 80 years ago the mining industry saw an advertisement of a machine manufacturer: ?One man ? one machine?, meaning the productivity gain by using a pneumatic rock drill instead of manual tools. Mechanization in mining had started. In the 1950's and 1960's when mechanization progressed the word could be transformed into the meaning of ?one man ? one drill rig?. During the 80's automatic functions were added to the machines. Automation started. In the 90's, the first autonomous machines were seen, transforming the advertisement from the 1920's into ?one man ? multiple machines? operated from a remote control room. Soon, the productivity gain achieved by pure automation will also be flating out meaning that the margin cost of further productivity gain will be inefficiently high. What next? In mining operations there is still a high potential of unused productivity lost by ?trivial? things like organization, logistics and operational management. Changing the focus from mechanization and automation towards optimizing the overall mining process will unleash another big potential for cost cuttings and for enhancing efficiency of production. Optimizing an overall process is a task of much higher total complexity compared to an isolated machine automation focus. And a successful process integration requires the collaboration of machine vendors, infrastructure suppliers, IT services and the mine itself. It requires a number of of important preconditions to be fulfilled: ? Integrated IT systems with seamless interfaces between all components and peripherals involved ? Real time information access in all locations ? Real time overview of all operational aspects A crucial aspect for all of these issues is a seamless communication both above and also under ground and IT interfaces which are easy and price efficient to implement. This paper highlights ways to achieve productivity gains by process optimization. It also discusses needs for industry wide activities in order to enable cost efficient performance of mine process optimization projects.

Oct 1, 2009

By Hyung Sup Choi

The preparation of high-purity zirconyl compounds was studied in order to develop an economical process for obtaining pure zirconium via the caustic fritting of zircon sand. The direct dissolution of caustic frits with concentrated hydrochloric or nitric acid at 80c. followed by the addition of a small amount of acidified gelatin, gave high-purity zirconyl chloride or nitrate. The addition of a small amount of gelatin caused a mutual flocculation between colloidal silica and gelatin. The precipitation of this silica floc markedly lowered the content of silica in the product. The silica content of the compounds (or solution) so produced, generally less than 100 ppm., was sufficiently low for tributyl phosphate extraction for nitrate solutions. It was found that the degree of purification de-pends not only on the procedures employed but also on the nature of the frit itself. Silica was more effectively eliminated from the fritted product produced at higher temperatures, and less silica was present in the com-pound prepared from the frit produced in a shorter heating time. In order to ascertain the nature of the

Jan 1, 1965

By Mark Rantapaa

Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the Autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the Open Pit and Process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput. Better fragmentation and a subsequent increase in mill throughput were achieved through the use of: 1) Electronic caps for more precision and flexibility, as well as for allowing extremely fast shots. 2) Explosives with a higher velocity of detonation (VOD), to provide for improved shock energy. 3) Improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by six tph in 2003 due to the improved fragmentation of the hard ore. Barrick Goldstrike?s D2M initiative includes roaster ?hard ore? (BWI >17), as well as autoclave ?hard ore? (BWI >15). Approximately six million tons of D2M material is expected be shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs.

May 1, 2003

By Marc C. Bétournay

Under the requirement to define the economic advantages of using hydrogen fuelcell vehicles, a broadscoped project was initiated to quantify the costs associated with operating fuelcell vehicles and diesel vehicles. While ventilation savings are clearly an advantage for the former, a complete and detailed analysis of this and other operational and capital cost elements was undertaken in order to provide the mining industry with factual information in considering the changeover from one technology to another. This article outlines the results of the investigations to date defining the costs/benefits associated with: capital purchases, operations (electrical/diesel, mine air heating fuel, ventilation, openings, surface and underground infrastructure, maintenance, labour, etc.), delivery of energy, regulatory obligations, and mine production. Considerations are given to the type and size of a mining operation, the depth, and location in North America. Significant ventilation power, equipment and infrastructure savings are possible with the application of fuelcells for shallower mine applications. At depth, where heat is an issue, there is a reduction in benefit. Specific qualifiers such as minimum air velocities, dust dilution, shaft and heating system velocity limits must be considered on an individual mine basis. While the capital cost for fuelcell mining equipment is currently higher than diesel versions, the high cost of fuelcells is anticipated to be reduced significantly in the near future with the intensification of manufacturing. In either case the operational savings would probably be sufficient to balance the supplementary capitalization costs. A comprehensive cost-benefit report will be issued in the near future.

May 1, 2003

By Stanislaw Trenczek

Natural hazards such as rock bumps, methane, coal dust explosions, airborne respirable dust, outbursts of gas and rocks, water, radiation caused by natural radioactive materials, spontaneous fires, and climatic hazards, occurring in the Polish hard coal mines, should be controlled. These hazards are characterized by different scale levels numbered from 2?5. To recognize the amount and levels of hazards, research works were carried out in 109 mining districts of mines belonging to Jastrzebska Spólka Weglowa, Katowicki Holding Weglowy and Kompania Weglowa. These are 86 % of all mines and could be regarded as representative of the majority of Polish mining. The hazards have been classified as regards the frequency of their occurrence as: commonly occurring ? with a frequency of 100 % (like airborne respirable dust and fire hazards), high occurrence frequency ? frequency from 60 to below 100 % (methane hazard ? 83.5 %, coal dust explosion hazard ? 92.0 %, and water hazard ? 99.1 %), medium occurrence frequency ? from 30 to below 60 % (rock-bump hazard ? 52.3 % and climatic hazards ? 51.4 %), and episodic occurrence frequency ? below 30 % (outburst of gas and rocks and radioactive hazards). The dynamics of effects of growth in hazard levels to their intolerable values is diverse. Some of them are passive in nature, which allows for longer observation of changes and appropriate early response (as for climatic and spontaneous fire hazards). However the majority of them take on the character of disasters, like methane or coal dust explosions and damage of the excavation structure ? as occurs after a rock-bump or rock outburst; and creation of an atmosphere unfit for breathing ? during open or spontaneous fires, or after gas outbursts containing methane. There are also latent hazards whose effects do not influence indeed a process of production; however they are detrimental to health when a worker is exposed for a long time to airborne respirable dust and radiation. For other types of hazards a level of danger may be only estimated. Since the systems monitoring allows a wider range of control, therefore, aside from rock-bump and methane hazards, there are monitored also fire hazards including measurements of other air parameters (velocity, pressure, humidity, temperature, O2, CO2 concentration). A few types of monitoring systems are used in Polish mines, like the monitoring systems for environmental parameters such as SMP-NT, SMP-NT/A, the telemetric systems CST-40, CST/A, including the computer-aided system for methanometry control officer SWµP, the computer-aided measuring systems KSP-1, KSP-2, KSP-2C, or the production and safety control system VENTURON. The underground part of the systems monitoring of natural hazards contains measuring devices and equipment for automatic control (power-off) of machines and electric devices in case of increased methane hazard. The surface part of the monitoring system allows the measuring data to be visualized and pre-alarm (warning) and alarm states to be displayed. Furthermore it makes it possible to archive and report the data and to control the underground supply and signalling devices. The EMAG Institute developed monitoring methods to extend a measuring range of monitored parameters (such as methane and fire hazards) as well as to monitor so far unmonitored hazards like dust hazards (by continuous monitoring of dust levels in mine air) and climatic hazards (by online monitoring climatic parameters of mine air).

Aug 1, 2013

In some parts of the world explosions in mines are more commonplace events. Even in the more developed nations explosions have occurred in recent times. In some cases these mines have significantly lowered their lost time injury frequency rates and as such considered themselves to be ?safe? operations. The consequence of these explosions has been devastating. It is not just the loss of those underground, but also to the families that have lost people in them and the broader community that has lost friends, income, business opportunities, and in many cases support and sponsorships. It begs so many questions, ?What went wrong??; ?Why were the circumstances not foreseen??; ?What could have been done to prevent it??; ?How is it that no one stopped it, reported it, fixed it etc.??. Being held accountable for negligence, should not be overlooked, however this may not aid the processes required to find all the answers. If the nature of explosions is understood, the circumstances and tools to prevent them are readily available then the occurrence and reoccurrence are due to weaknesses or inadequacies of the systems of work or in the implementation of them. This paper restates the fundamentals of gas explosions, examines the options to control the underground environment through ventilation, gas management and monitoring, education and training. Case studies have been used to examine systematic failures in ventilation management. In some of these cases it is not so much, the system that had been developed, but the interpretation and implementation of the system that resulted in the failure and subsequent loss.

Aug 1, 2013

By J. B. Evans

"NORMALLY the duties of the exploration engineer and geologist cover the initial, and possibly, the most important phase of mining property evaluation; that phase being the presentation of an opinion of the property's ore reserve potential in terms of tonnage and grade. The prime objective of this pa-per is to outline one method of bridging the wide gap that lies between a know ledge of a property' s tonnage and grade potential and an appreciation of the value of that property in dollars and cents.THE PRESENTATION OF PROPERTY EVALUATIONThe engineer engaged on a mining property evaluation, regardless of whether he be an independent consultant, or a company employee, has as his goal, the presentation of his appreciation of the property's potential value or worth within terms of reference acceptable to his principal.To furnish a complete evaluation report, the evaluator must firstly study all aspects pertaining to the particular property under consideration, then present his appreciation of the property's worth in some tangible form. The ultimate presentation is one giving a Present Value of the pro pert y in terms of monetary exchange. Such an idealistic presentation is not always possible; typical preventives being -insufficient reliable information, limited time, Jack of ability and absence of definite direction."

Jan 1, 1960

The Red Lake greenstone belt is an irregular mass of lavas sedimentary rocks and intrusives which is approxiately 35 miles long 18 miles wide and 7 miles deep. Basaltic volcamcs are the oldest rocks w1thm the belt. They are believed to have been laid down on an ancient crust which is at least 3 billion (3 x 109) years old and was composed partly of sediments. The basaltic rocks are overlain by acid volcanics and sedimentary rocks which have been complexly folded and are preserved as a down-folded remnant of younger rocks within the older crust. The volcanics and sedimentary rocks of the greenstone belt have been cut by intrusives with a wide range of composition. The emplacement of the intrusives and the accompanying regional metamorph-ism which terminated the orogenic activity in this area are believed to have occurred approximately 2.4 billion years ago. The basalts and many of the basic and ultrabasic intrusives undoubtedly had their source in the sub-crust or mantle. At least some of the granitic intrusives are believed to have had

Jan 1, 1965

By D. A. Beattie

Talc is a commonly encountered gangue mineral in metal sulfide flotation. Talc is naturally hydrophobic, resulting in high recoveries if polymeric depressants are not used to specifically reject this MgO containing mineral. We have studied the adsorption of a selection of polymers onto talc using a variety of techniques. Adsorption isotherms have been determined using ex situ depletion techniques and in situ ATR-FTIR spectroscopy has been used to determine adsorption kinetics. Adsorbed layer thicknesses have been determined for the polymers on cleaved talc surfaces using the AFM. The effect of the adsorbed polymer layer on the properties of the talc surface has been quantified through contact angle measurements and single mineral flotation tests. Distinct correlations are observed between the adsorbed layer properties and the flotation performance of the polymers. These observations are discussed with reference to the bubble-particle attachment process and the molecular structure of the polymers.

Jan 1, 2006

By Kurt Tischler

This paper presents the field experience of Siemens with regard to Gearless Drives in the mining industry ? We consider the elapsed production hours of Siemens Gearless Drives to be extensive enough to provide a reliable estimation of availability calculated on the basis of data representing repair time, downtime, and operating time. The users of Siemens Gearless Drives confirm an availability of more than 98% after exclusion of some major issues. The paper addresses all of these major issues of Siemens Gearless Drives, describes successfully applied corrective measures, explains the influences on the design of the drives, and lists the downtimes associated with each of these issues.

Jan 1, 2012

By Barrie Robb

Outline 1. Mackenzie Aboriginal Corporation (MAC) 2. ACR background 3. ?Learning from Experience? project - What - Why - lessons 3. How Industry could contribute to sustainable Aboriginal communities 4. Concluding words What is the Mackenzie Aboriginal Corporation (MAC)? ? Aboriginal owned ? Established construction capabilities ? Commitment to development of northern resources ? Partners have extensive experience

May 1, 2008

By Christian M. Bauer

Modern surface mines are among the world's largest single consumers of diesel fuel. A typical mine site can consume in excess of 200 million liters of diesel fuel per year. Delivered diesel fuel is not necessarily clean. Depending on the mode of transportation, handling practices and local climate, incoming bulk fuel can contain up to 20 mg/L suspended solid contaminants and also significant quantities of free water, which can amount to substantial quantities ? for a typical mine site 200 to 400 kg of dirt per year. Standard on-board fuel filters are not designed to handle high levels of contamination, and most engine manufacturers have specific fuel cleanliness requirements to ensure reliable engine operation. New developments in fuel injector technology, such as high pressure, common rail injectors require even cleaner fuel. In order to ensure reliable operation, it is therefore recommended to control particulate contamination throughout the entire Diesel supply chain - from the bulk storage on mine sites to the injection systems on-board through the use of particulate filtration and liquid coalescence technologies. In this work, the author introduces a comprehensive approach to contamination control for the entire fuel supply chain, and discusses the benefits of using advanced filtration and separation technologies, with a particular focus on the requirements of modern high pressure, common rail (HPCR) fuel injection systems.

Nov 1, 2011

By Douglas C. Fraser

A DIGHEM survey was flown in the Belford-Montcalm Township area of Ontario in November 1975. This 600-linemile survey resulted in the detection of 134 EM anomalies. The Montcalm Township copper-nickel discovery yielded a single-line anomaly having a conductance of 154 mhos. This anomaly was highly visible because (a) it had the highest conductance in the survey area, (b) it correlated with a 175-gamma thumbprint-shaped magnetic anomaly and (c) it was isolated from long conductive bands. The deposit is a copper-nickel pyrrhotite body which occurs in gabbro and strikes north-south, parallel to the flight lines. The DIGHEM survey was flown north-south, because the exploration program was primarily concerned with locating copper-zinc sulphides in the east-west-striking felsic volcanics. The flight line passed close to the deposit and yielded a 9-ppm anomaly on the chart record. The computer analysis showed that a deposit of exceptionally high conductance (154 mhos) caused the relatively weak (9 ppm) anomaly. The ground follow-up program of magnetics and EM led quickly to the discovery drill hole, which penetrated the orebody in September 1976. Subsequent geophysical surveys consisted of horizontal-loop EM, pulse EM, magnetic and induced polarization surveys over an area of about 8 claims. In addition, a detailed DIGHEM" airborne survey was flown at a line spacing of 100 m to evaluate the entire property of 620 claims. This detailed survey yielded EM conductor maps and contour maps of resistivity, magnetics and enhanced magnetics.

Jan 1, 1978

By P. C. Benedict, J. A. Titcomb

"The following description of the geology of the Northern Empire mine is recorded by the senior author, but is based on the observations and complementary mapping of both authors.The Northern Empire mine is a mile east of Beardmore, and 100 miles northeast of Port Arthur, Thunder Bay district, Ontario.Production started in March, 1934, and terminated in September, 1941. The total number of tons milled was 425,866, from which 153,103 oz. gold was recovered. The lowest level from which ore was mined was the 1,900- foot, but considerable drifting was performed on the 2,075-foot and 800 feet on the 2,415-foot, the deepest level,The vein strikes about N.72°E. and has an average dip of80°S. In stoped sections the quartz averaged about 2 feet wide. On the 1,725-foot level it was drifted on continuously for more than 7,000 feet. In the mine as a whole, practically no commercial ore was found beyond points 1,400 feet west and 1,800 feet east of the shaft. Conspicuous wall-rock alteration extended throughout this section, but not much beyond these limits. There was some splitting of the vein and widening of the alteration halo on the lower levels. The average general colour of the quartz changes with depth .The vein is in 'Keewatin' lava flows, to which it is almost conformable. It lies only a short distance south from the 'Timiskaming-Keewatin' contact ( Fig. 2). This contact is marked by a black graphitic fault. So far as is known the fault is parallel, or nearly parallel, with the flows in strike, but dips at 72°S., which is 5° flatter than the average dip of the overturned flows. A post-vein, almost flat sheet of diabase about 550 feet thick cuts outthe vein from about the 650- to the 1,200-foot level ( Figs . 1 and 3). If it was intruded along a fault, the fault had only minor displacement. A strong alteration halo extends to 200 feet above and below the diabase. The vein was conspicuous but in large part it was below ore grade for 100 feet or more above and below the diabase.-"

Jan 1, 1954