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By Marty Hudyma

There are five independent seismic source parameters: seismic energy, seismic moment, source size, location, and time. These parameters are investigated primarily for evaluating seismic hazard and understanding seismic source mechanism(s). Broadly, seismic hazard is the likelihood of occurrence of an event of a given magnitude. Seismic source mechanism is the mode of rockmass failure that causes the seismic event. Most mine seismicity analysis techniques use a combination of a few of the independent source parameters. In literature, time is perhaps the least discussed and most underutilized of these five parameters. This paper discusses three applications of time to understand both seismic hazard and seismic source mechanism in mines. The first application is time history analyses, which focuses on how other parameters of interest vary over time. Examples are presented to show how time history analyses can give information about both seismic hazard and seismic source mechanism. The second application is analysis of time-between-events. This technique can give insight into seismic source mechanism. The final application is phasor analysis using the Schuster test. This method can be used to investigate how seismic source mechanisms may change over time. For both time-between-events analysis and phasor analysis, there are important implications with regards to scale dependence and the breakdown of self-similarity of mining-induced seismicity.

Jun 1, 2012

By Zhang Wei

"Pulang Copper Mine is located in Shangri-La county, Diqing Prefecture, Yunnan Province, with currently defined copper reserve of 4.8 million tonnes of copper metal and an average grade of 0.34% Cu. The mineralized zone in a dome shape is 2,300 m long, 600–800 m wide, and 1,000 m high. At present, the project is at a construction phase, with a first-stage mining and processing capacity of 12.5 million tonnes of ore per year. Ore haulage is planned via a drift and ore pass development system. The cavability of mineralized rock is classified into three types (II, III, IV), with type III accounting for more than 98% of the total reserves. The cavability of the orebody is generally considered to be good and block caving mining method is planned. Semi-autogenous grinding and ball milling are adopted for the mineral processing. The tailing dam construction method is a center-line method.INTRODUCTIONAs the China's largest underground nonferrous mine, Pulang Copper Mine is located in the northeast of Shangri-La County, Diqing Prefecture, Yunnan Province, China. It is 62 km northeast of Shangri-La city. Shangri-La County is a Tibetan-dominated, multiple-ethnic region, with a population of approximately 163,000 in 2009. The county is rich in mineral and water resources, thriving with tourism. Its economy is also dominated by agriculture. To date, the defined copper reserves at the Pulang Copper Mine is 4.8 million tonnes of copper metal at an average grade of 0.34% Cu. In addition, it contains a gold reserve of 145 tonnes, a silver reserve of 2,754 tonnes, a molybdenum reserve of 0.19 million tonnes, and a sulphur reserve of 10.5 million tonnes. The first-stage mining and processing capacity is planned at 12.5 million tonnes of ore per year. When it ramps up to this production rate, the mine will produce copper concentrate containing 50,000 tonnes of copper and molybdenum concentrate containing 968 tonnes of molybdenum. A drift and ore pass system is planned for ore haulage and mining method is a block caving method. Semi-autogenous grinding and ball milling are considered for mineral processing. A center line dam is adopted for the tailing dam construction (Feng, 2010; Feng, Li, & Wang, 2011; China Enfi Engineering Corporation, 2014)."

Jan 1, 2016

By T. Yalcin, S. Brunet

The flocculant-assisted hydrocyclone involves the addition of a flocculant to the cyclone feed for the purpose of obtaining a clear cyclone overflow, and thereby eliminating or reducing thickener requirements in tailings disposal operations. This paper describes the testing of this concept on the iron ore tailings of Quebec Cartier Mining Company's Mount Wright Concentrator. The current practice at Mount Wright makes use of conventional hydrocyclones and thickeners for the disposal of their tailings, which are generated in a spiral gravity separation circuit. The test work was conducted primarily on their cyclone overflow product which becomes the feed to the thickeners. A detailed study was carried out to determine the sedimentation properties of these tailings in terms of their response to a variety of flocculating reagents, and to varying conditions of pH, pulp density and flocculant dosage. The tailings were then processed in a laboratory hydrocyclone with the aid of flocculants. The use of a shear resistant flocculant, in particular, was found to yield cyclone overflows with low solids contents. Based on the test results obtained, a conceptual flow sheet has been proposed for the treatment of the iron ore tailings at the Mount Wright Concentrator.

Jan 1, 2004

By J. Yue

The particle breakage kinetics, product size and size distribution, as well as grinding limit for quartz suspensions in a horizontal stirred mill are investigated. Results of grinding studies on quartz suspensions in a horizontal stirred mill confirm "first-order" particle breakage rates. A comparison of equation fits reveal that the product size distribution from stirred mill is best represented by the Rosin-Rammler equation when compared to the Gaudin-Shuhmann equation, but results fit poorly as particle size below five microns. A method of determining breakage rates versus particle size is demonstrated which shows that the 10% top size fraction is most appropriate for the determination of specific breakage rates. The method is used to demonstrate the relationship between particle breakage rate and particle size. As the feed particle size becomes smaller, the size reduction ratio decreases and approaches a grinding limit which depends on the effective stresses created in the mill.

May 1, 2004

By R. W. Brock

This subject is too broad and comprehensive to be dealt with adequately and authoritatively in this paper. It calls for the knowledge and experience of many men, but the results from such collaborative effort would be of great value, particularly if similar reports of the principal mining districts of the world were made on a standardized basis so that conditions everywhere might be directly and accurately compared. In considering conditions affecting mining in British Columbia, unfavourable as well as favourable factors must be taken into account. The unfavourable are apt to loom large and to be exaggerated rather than minimized; for it is human nature to see the blackness of the cloud rather than the silver lining; to think that one's own undertaking is beset with peculiar difficulties, and to attribute lack of greater success to out-side causes rather than to personal shortcomings. It should be recognized, however, that there is no country where the conditions for mining are ideal. The ideal mining country is the product of imagination, invested with every favourable condition found anywhere, but with none of the unfavourable conditions that are always present in reality. So if British Columbia has some handicaps to the industry, it is in good company. What is important is that the advantages compensate for the disadvantages, that the balance will compare favorably with that of competing states, for mining, like every other industry is competitive, and the cost of one's product must have a definite relationship to its price in the world's market.

Jan 1, 1924

By E. Ghali, N. Sorour, G. Houlachi

"The binary Fe53Mo47 and ternary Fe54Mo30P16 coatings have been electrodeposited from citrate-based electrolyte on mild steel (MS) substrates. The electrodeposition has been conducted for 6 hours at 20 mA cm-2 and 30°C. The electrochemical tests were carried out in chlorate solutions containing 300 g L-1 NaCl and 4 g L-1 K2Cr2O7 at pH 6.4 and 80°C. A number of surface characterization techniques such as SEM-EDS, XRD and EMP were used to study the microstructure of the alloys. The electrocatalytic activity of these coatings was investigated using steady-state polarization and galvanostatic technique. This study revealed that the Fe-Mo-P coating could be considered as a promising cathode material for the hydrogen evolution reaction (HER). The results showed an important decrease of hydrogen overpotential for Fe-Mo-P alloy as compared to that of Fe-Mo and especially MS which is a traditional cathode in chlorate industry. The HER overpotential for Fe54Mo30P16 at current density of 250 mA cm-2 was decreased by 30% in comparison to that of MS (1029 mV), and by 16.5% to that of Fe53Mo47 coating (857 mV).INTRODUCTIONSodium chlorate is used for manufacturing of several daily consumption products. This chemical is mainly employed for the production of chlorine dioxide (ClO2) that is a bleaching agent used in the pulp and paper industry. The ClO2 is also consumed for generation of perchlorates, chlorites and other chlorates, as an herbicide and in uranium processing (Cornell, 2002). Sodium chlorate is produced industrially via following overall formula in un-divided electrochemical cell (Nylén & Cornell, 2009):"

Jan 1, 2016

By J. D. Botsford

Westmin Resources Limited's H-W orebody on Vancouver Island is a copper/lead/zinc massive sulphide deposit that has been in production since 1985. The sulphur content of the ore averages 28% and in some stopes is as high as 53%. Several minor secondary sulphide dust explosions have occurred in development headings and cut and fill stopes, but as yet no known explosions have occurred in blasthole stopes. This pa:per reviews the history of sulphide dust explosions in the H-W Mine, factors contributing to the explosions and the preventative measures taken to control them.

May 11, 1988

By D. C. Fraser

"Geophysical Engineering and Surveys Limited of the Keevil Mining Group have routinely conducted ground surveys with VLF-EM receivers for the past two years. Both Crone's Radem and Ronka's EM16 have been used.VLF-EM dip-angle data often yield complex patterns which require considerable study for a proper interpretation. A method was developed which allows field operators to transform the noncontourable dip angles into contourable data, producing conductor patterns which are immediately apparent to exploration personnel untrained in VLF-EM interpretation.VLF-EM contoured data generally peak very close to the top of a conductor, thereby allowing drill holes to be spotted accurately. However, the data generally should not be used alone to select drill targets because structures may be sufficiently conductive to yield strong anomalies. Thus, magnetic and/or vertical-loop EM correlations may be considered as necessary criteria for drilling.VLF-EM surveys can replace IP surveys in certain environments. For example, the Restigouche orebody in the Bathurst camp of New Brunswick yielded a VLF-EM anomaly as distinct as that obtained by IP, although the body did not respond to vertical-or horizontal-loop EM. However, the cupriferous breccia pipes of the Triba mine near Batchawana, Ontario yield strong IP anomalies but not VLF-EM anomalies, illustrating that disseminated ore targets should be sought with IP rather than with VLF-EM."

Jan 1, 1971

By N. T. Avard

THE Joggins coal field, Cumberland county, Nova Scotia, is on the easterly side of Chignecto bay, at the head of the bay of Fundy. In area, so far as proven, the field extends easterly from the town of Joggins about fifteen miles to Chignecto. The distance across the outcrops of the several seams exposed is approximately one mile. HISTORY Early records of coal mining in this locality are somewhat obscure, but it is known that prior to 1750 the French settlers were mining coal for their own use from the seams which outcrop in the floor of the bay adjacent to the shore, where, at low tide, the reefs are bared for a mile or more. Coal was also mined from the seams outcropping in the cliffs. It is known, too, that at Joggins coal has been mined commercially for over one hundred years. At first, all shipments were made by water, but in 1882 a railway connecting with the Intercolonial railway at Maccan was built to serve this field. GEOLOGY Due to the abundance of fossils in the strata forming the Joggins cliffs, this area was for many years a mecca for geological students from all over this continent. A 'sunken fcrest' in the shoreline was of particular interest but, due to constant erosion by the sea, this has apparently been all washed away. On the Joggins shore, the cliffs stand sixty to one hundred feet high, and six workable coal seams, with numerous smaller ones, are there exposed. Others outcrop in the reefs extending from the shore toward the bed of the bay. In working underground, fossilized trees are often found immediately overlying a coal seam, and standing at right angles to the pitch of the seam. This is said to be an unusual condition. In most cases, the bark of the tree is a fine-quality coal, with high carbon content, whereas the pulp has turned to 'stone'. There is a definite tendency for the coal to run out, or turn to shale. One seam, workable two miles from the shore, has almost completely disappeared in the outcrop at the shoreline. ? It was thought that a large area could be mined under the bay from an opening near the shore, but the first submarine level had to be abandoned at a distance of 4,000 feet, where the coal became very dirty and shaly, and the mine able area to the westward became more restricted as the mine was developed to the deep. This tendency is common to all seams.

Jan 1, 1944

By Man-Chao He

One of the critical problems involved in deep coalmines is unusual gas emissions. Many researchers agree that there is a relationship between coal gas emissions and geological features such as tectonics or geological disturbances, gas content, properties of the coal and rock and the mininginduced stress state in the coal seam and rock. Thus, the present paper intends to investigate complex mechanical phenomena during the process of gas emission in underground coal-mines. A program of laboratory testing was undertaken to study the effects of temperature and pressure on mechanisms of gas emission. It must be noted that this paper describes new techniques developed to simultaneously measure deformation and gas pressure, as well as flux during the test, taking the characteristics of gas transport into consideration under certain temperature and pressure conditions. The results indicate that under certain temperature and pressure conditions, gases adsorbed to coal start to desorb, and increase the pore pressure. High pressure gases entering coal fractures can generate high tensile stresses near the crack tips, leading to crack propagation and coalescence, which in turn can cause the specimen to dilate. From the experimental viewpoint, these test results may help us discern why mining seismic events can trigger gas emissions.

Aug 1, 2013

By Sudarshan Martins

The measurement of acoustic signals produced by a tumbling mill has been previously used to determine the operating state of the mill and correlate the variations of the sound intensity with the operating conditions of the mill. Separately, the discrete element model (DEM), a software simulation of the mill, was developed to provide insight into the operation of the mill. Presently, there has not been much work reconciling the DEM simulation of the mill with the acoustic signal. Working from basic principles of linear, time-invariant systems, agreement between an acoustic DEM simulation and the measured signal is sought. First, the impulse response function of the mill is measured. The DEM provides the forces applied to the mill shell as a function of time. A convolution of these simulated shell forces and the transfer function gives the simulated acoustic signal. This signal is compared to the measured acoustic signal, both in the time domain and the frequency domain. Finally, a discussion of the results is given.

Jan 1, 2012

By Brian Lewis

"IntroductionThe leaching method selected for the dissolving of uranium ore depends in part on the physical characteristics of the ore, as well as the uranium mineralization. There are two main methods of leaching employed in uranium circuits in North America, one being ""Carbonate Leaching"" on sandstone, and pitchblende type ores, and ""Acid Leaching"", on quartzite type ores.This chapter deals with the acid leaching of uranium ores found in the Elliot Lake area, using sulphuric acid, for the leaching reagent, and ""pachucas"" for the contactor.The basic leaching process involves the pregrinding of the ore and the mixing of the ore with hot sulphuric acid, the mixture is air agitated, the air being used to oxidize the ore as well as produce agitation. The chemical reaction is as follows: Uranium Oxide + Sulphuric Acid = Uranyl SulphateThe following equations show the actual dissolution of the ""Hexavalent Uranium"", which show that more than one ion or complex of uranium is possible.Uranium DissolutionsI. UO, + 2H-(UOJ + H,O2. (UO,) + SO, = -UO, SO, (Uranyl Sulphate)3. UO, + SO,-(UO, (SO,),)=4. (UO, (SO,),)= -(UO, (SO,),)'Test work carried out in the laboratory as well as in the plants has determined the most efficient methods of extracting the uranium from the ore. A very important factor that has to be determined during initial test work are the amount of acid consumers in the ore. Within the Elliot Lake orebodies are minerals such as chlorite schist, diabase, and basement material, all very high acid consumers, consuming up to 1000 lbs. of acid per ton of ore. Of these minerals only the chlorite schist contain any uranium at all.The following are the operating parameters that have to be controlled in the plant:I. sulphuric acid concentration2. temperature of the mixture3. agitation4. liquid solid ratio5. reaction time6. particle size of ground ore"

Jan 1, 1989

By J. Groppo, W. Zhang, R. Honaker

"The flotation of monazite is depressed when using hydroxamic acid as a collector in the presence of calcium ions which may exist due to the dissolution of minerals such as calcite. Minor dosages of sodium hexametaphosphate (SHMP) were found to effectively depress calcite, whereas the flotation of monazite was not impaired in single mineral flotation tests. However, in a mixed mineral flotation system, monazite flotation was depressed significantly. The mechanism of hydroxamate adsorption on monazite and calcite, the depression mechanism of calcite on monazite, as well as the depression mechanism of SHMP on calcite and monazite were studied using micro-flotation, electro-kinetic, and adsorption tests. Findings indicate that the adsorption of hydroxamate on monazite was due to chemisorption while adsorption on calcite was a result of physical interaction. SHMP significantly increased the negative charges of calcite surfaces which depressed the adsorption of the hydroxamate anions on the calcite surfaces due to an elevated electrostatic repulsion force. When calcium-rich minerals such as calcite are mixed with monazite, the calcium ions dissolved from the mineral surfaces specifically adsorb onto the phosphate oxygen sites on the monazite mineral surfaces thereby causing depressing effects. The addition of SHMP to suppress collector adsorption on the calcite surfaces interacts with the calcium species that were specifically adsorbed onto the monazite surface, which prevents hydroxamic acid adsorption onto the rare earth oxygen sites due steric hindrance and results in the flotation depression of monazite. INTRODUCTIONAs one of the commercial rare earth ores, monazite has been widely exploited to produce additives for catalysts, batteries, alloys, etc. Because of the complexity and the fine nature of some monazite ores, methods such as gravity, magnetic, and electrostatic separation to treat beach sand monazite fail to produce satisfactory concentrates, suggesting the use of floatation is warranted (Cheng, Holtham, & Tran, 1993). The primary associated minerals of monazite ores include ilmenite, quartz, zircon, rutile, sillimanite (Dixit & Biswas, 1969; Pavez a& Peres, 1994, 1993). Using sodium oleate as collector for monazite has been reported in many studies (Cheng et al., 1993; Dixit & Biswas, 1969; Pavez & Peres, 1994, 1993). Several investigations have reported maximum floatability of monazite occurring at pH values between 8 and 9 (Cheng et al., 1993; Dixit & Biswas, 1969). A study conducted by Pavez and Peres (1994) compared the use of hydroxamate and sodium oleate for the treatment of a monazite ore and found that hydroxamate significantly improved the grade of rougher concentrate."

Jan 1, 2016

By Charles "Chick" Rodgers, Anthony Sarion

"With declining feed grade and increased production targets, it became necessary to upgrade Key Lake's eight stage counter current decantation (CCD) circuit. Following laboratory trials, mill operations recognized that dilution of the feed slurry and buffering of the feed density variations would improve thickener throughput. Plant testing resulted in the installation of Outokumpu's Supaflo ""Floe-Miser"" system. The circuit's flowsheet, instrumentation and control strategy were also upgraded along with the thickener feedwell modifications. The paper will also discuss these modifications and the implementation of the current control strategy.IntroductionCameco Corporation's Key Lake operation is the largest single uranium producer in the world. Current production is fourteen million pounds of uranium oxide (U 308) per year. It is owned 2/3 by Cameco and 1/3 by Uranerz Exploration and Mining with Cameco as the operator.The mine is 570 kilometres north of Saskatoon on the southern edge of the Athabasca basin. Access to the mine is by an all-weather road and a private airstrip.Process DescriptionThe Key Lake milling process consists of five individual plants: crushing and grinding; leaching and counter current decantation (CCD); solvent extraction; yellowcake precipitation and ammonium sulphate crystallization; and bulk neutralization (Figure 1 -Simplified Mill Flowsheet). A detailed mill flowsheet can be found in the appendix."

Jan 1, 1998

By H. Nejati

Experimentally, the Semi-Circular Bending Moment (SCB) fracture toughness test results of Basalt Specimens Under Illumination (BSUI) have shown reduction in fracture toughness and failure force as a result of micro-cracking. The fractographic investigation of BSUI confirms initiation and extension of micro-cracks. Determination of a relation between strength reduction (herein fracture toughness reduction) and density, location and orientation of thermo-mechanical induced cracks due to microwave radiation is critically important. Numerical modeling can bridge strength reduction and the density of thermal microcracks generated due to microwave radiation. Discrete Element Modeling (DEM) is a power tool for simulation of micro-crack initiation, coalescence into macroscopic fractures and failure mechanisms in brittle rock specimens under different stress regimes (herein combination of pure tensile stress due to SCB testing, and thermal stress due to microwave radiation). For this purpose, a DEM modeling of SCB testing of basalt using EDEM (i.e., a DEM based software). DEM models are calibrated according to results of experimental SCB testing as reported in previous papers. This paper first reviews some background data on SCB fracture toughness, and experimental results of fracture toughness of microwave treated SCBs. Then it proposes a new methodology for simulation and validation of rock samples exposed to microwave illumination with regard to experimental results, and discusses the correlation between fracture toughness of BSUIs and density of micro-cracks, which is attributed to applied microwave power and duration of illumination.

Aug 1, 2013

By J. Y. Kim

This paper presents a novel action recognition method for observing human workers using interactions between actions and related objects on an internal construction site. This method can be used to measure work rates for labour productivity monitoring. This monitoring is critical because the performance of a construction project is significantly impacted by labour productivity. However, construction sites are generally crowded with a large number of workers and objects. Such congestion disrupts the accurate, automatic recognition of construction workers? actions. This congestion is one reason that existing automatic action recognition studies of construction areas mainly focus on workers? actions themselves. However, the crowded conditions mean that sites could offer a great deal of clues that could be used for automatic action recognition. According to psychological studies, interactions clearly take place between human actions and related objects, such as between hammering and a hammer. Humans use these interactions to recognize actions or objects more accurately. On the construction site, workers, materials, tools, and equipment are carefully planned out ahead of actual construction. The categories of workers and objects are pre-defined and, as noted, specific interactions define relations between worker actions and objects. In this paper, the interactions are limited to human workers and their hand-held objects. Action recognition results can be combined with hand-held object information to improve recognition accuracy. With the limited interactions, experiments in this paper show a significant improvement in action recognition. This paper describes the utilization of these interactions to improve construction action recognition accuracy based on human skeleton data and 2D color video from Microsoft KINECT sensor.

Aug 1, 2013

By The Staff

"A general description of the equipment, personnel and work sequence •being used in the sinking of a circular, concrete lined, 14 foot diameter shaft which at present is at a depth of 2,484 feet. Equipping, lining and sinking of the shaft is being carried out concurrently and waste is re-moved using a mechanical mucker.INTRODUCTIONTHE BUCHANS UNIT of the American Smelting and Refining Company operates a group of mines at Buchans, Newfoundland. Buchans is in the centre of the Province (Lat. 48°47'N.; Long. 56°50'W.), five miles north of Red Indian lake at an elevation of 900 feet and is accessible by 37 miles <Jf private railway which connects with the Canadian National railway at Millertown Junction, and by 47 miles of gravel highway, which connects with the Trans-'Canada Highway at Badger."

Jan 1, 1959

By Hal. Oliver

MR.]. G. TRAILL: My only excuse for contributing to the discussion on Mr. Hall&apos;s interesting paper is that I had the good fortune to be employed at Noranda during those romantic years, 1927 and 1928, when construction was at its height. The mine was in course of being rapidly prepared and brought into production, and the initial difficulties in crushing-plant and smelter were being met and overcome. They were stirring days, and perhaps those members who were with the second Empire Mining and Metallurgical Congress in 1927 sensed the atmosphere of excitement and activity that prevailed. Early History. Noranda must surely possess some of the most remarkable ore-bodies known to mining men, and the story of their development is pure romance. Ed. Horne&apos;s faith in the property, and the persistence of Thomson and Chadbourne, were richly rewarded in the end, but only after some very thin times had been experienced. In those early days access to the district was by the Kenojevis river and various portages to Osisko lake, on the shores of which the mine and smelter and the town of Noranda now stand. But all the early work was done on the Chadbourne claims, more than a mile to the west; through the b~sh. I have read a log of the events of that period, and through the whole tale of hard work, discouraging developments, occasional shortages of food, and constant danger from forest fires, can be read the faith and persistence of the men in charge. The Chadbourne ore was of that well-known type which, though just too low-grade to pay (with gold at $20 per ounce), is yet sufficiently encouraging to lead one on in the hope of striking something better. It was only as a last resort that work on the Chadbourne claims was suspended and a diamond drill brought to the gossan-covered hill beside the lake. The diamond-driller told me his version (it may be exaggerated) of how the position and direction of the first hole were decided on. He was told, "You might as well set up your drill here, and drill in, say, that direction". I believe that the first hole went through the richest ore ever found at Noranda. After the drill had gone through about 150 feet of solid sulphide ore running 17 per cent copper and 4 dwt. of gold per ton, it passed into barren rock, but the diamond-driller expressed the opinion (I wonder how he knew)) that the hole would come into ore again before long.

Jan 1, 1937

By Stanley Davidson

"This description of the structural geology of the Beattie mine has been condensed from a more comprehensive paper published previously (4).The property is in western Quebec, a short distance east of the Ontario boundary on the extension of the so-called Porcupine belt into Quebec.According to the geological surveys of the Dominion and Provincial Governments the regional structure in the vicinity of the mine is an easterly pitching, overturned syncline with several thousand feet of Timiskaming sediments in the centre surrounded by Keewatin volcanics (1, 2, 3).The mine lies on the north limb of the syncline, and the Keewatin series in this locality is, with few exceptions, overturned, dipping steeply north and facing south.The mineralization is closely related in space, and possibly genetically, to a body of syenite porphyry intruded into the Keewatin series along the north limb of the syncline. No ore has been found very far from the syenite or related lath-porphyry dykes, and the largest orebodies are composite, consisting of bleached and brecciated volcanics ( primarily tuffs) adjacent to altered syenite porphyry, both silicified and mineralized with very fine pyrite and arsenopyrite. In addition there are important ore shoots following a fracture zone within the syenite."

Jan 1, 1954

By D. F. Sangster, P. J. Hood, G. A. Gross

"Some results are presented of an integrated geological and geophysical study of Precambrian magnetite-quartz iron-formation in the Kapiko Iron Range north of Nakina, Ontario. Detailed geological and topographical mapping was carried out in conjunction with detailed geophysical investigations such as vertical magnetic field, vertical magnetic gradient, hammer seismic, horizontal-loop electromagnetic and magnetic susceptibility surveys. In addition, oriented drill cores were obtained for magnetic polarization studies.Vertical-force magnetic anomalies within individual rock units showed a strong positive correlation with topographic relief. Moreover, magnetic intensity was found not to be quantitatively proportional to the magnetite content in the rocks, due to the presence of high remanent magnetization of the magnetite. Also, the remanent polarization direction was sub parallel to the plunge of the fold structure and mineral lineation in associated rocks.Vertical magnetic gradient measurements were found to be more accurate in locating buried contacts between magnetite-quartz iron-formation and country rock than the vertical magnetic force data.An in-situ magnetic susceptibility meter was used to measure the magnetite content of iron-formation, and the measurements were subsequently compared with vertical-force magnetic results.The results of the EM survey were inconclusive; some magnetite-rich zones produced anomalies in the out-of-phase component. whereas others did not. The reasons for such inconsistencies are not yet apparent.Longitudinal seismic wave velocities measured parallel to the bedding in magnetite-quartz iron-formation ranged from 10,600 ft/sec. to 14,500 ft/sec. The seismic velocity appears to increase with an increase in deformation of the rocks."

Jan 1, 1966