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By George Booth

In mining operations the cost of timber is an item of much importance, because the life of mine timbers is, in many cases, very short and, as the supply of the better grades becomes depleted, less durable kinds must be used. This, of course, tends to shorten still further the period of service-ability. While it is possible that concrete and steel may, to some extent, take the place of timber in mines, their high initial cost and the difficulty in installation will greatly restrict their use. Moreover, wood, besides being comparatively cheap to handle, possesses other desirable qualities, and for many purposes a satisfactory substitute is hard to find. Both the decreasing supply and the increasing price of timber make its more efficient utilization imperative. AGENCIES DESTRUCTIVE TO MINE TIMBERS Timber used in mines is exposed to destruction from many sources. Wear, breakage, and waste are responsible for much loss. Wood rollers and drum laggings must be frequently replaced on account of the constant wear by ropes. Unprotected timber in chutes and mills is also rapidly worn by abrasion, and track ties in main haulage ways get worn by the feet of mules, cut by ropes, etc. Large amounts of timber are broken by 'crush' and 'squeeze,' and much temporary timber is buried beyond all recovery in pillar workings and in those mines which resort to back filling. Decay and insect attack, however, cause the greatest damage. If not totally destroyed by one or both of these, the timbers frequently become so weakened that they break under the pressure upon them.

Jan 1, 1926

By D. C. Rance

"The Quintette Coal Limited property is located in the northeast coal area of British Columbia.A basic agreement with the Japanese steel industry was executed on January 27, 1981 for the sale of 69.5 million tonnes of Quintette metallurgical coal over a 14.5-year period. This contract period can be extended by five years by mutual agreement. Sale agreements have also been signed for the sale of 19.4 million tonnes of oxidized coal over a 15-year period.Work started on site development in the late summer of 1981, and at present, two of the four eventual pits-the McConkey and Frame-are under development.The pits are currently in a prestripping phase. These pits are notable for the stripping volumes that have to be removed from relatively small pit areas. In order to provide for the required detailed rapid short-range planning of these pits, engineering will be computerized, as will the truck dispatch system.The mining area lies 21.1 km from the plant site by road and the transport of raw coal to the plant is by means of a high-speed conveyor system which has a total length of 13.4 km with a vertical drop of 740 m.The surface plant facility was designed on a modularized basis to facilitate maintenance, and is designed to enable the use of gravity f low of raw coal and heavy media in the plant to minimize the use of pumps.The construction of the plant and mine site facilities is ongoing, and the first coal production is scheduled for early December 1983.IntroductionQuintett e Coal Limited is a Canadian company incorporated in the province of British Columbia in 1971. Denison Mine s Limited is the manager of Quintette's activities. Equity in Quintette Coal Limited is held by several shareholders, with interests as follows: Denison Mines Limited, 50%; Charbonnages de France International S.A., 12%; and Japanese interest, 38%."

Jan 1, 1983

By J. M. D. Wilson, W. Petruk, C. Coté

"The behaviour of minerals in the Mount Wright spiral circuit was investigated to find methods of improving iron oxide mineral liberation and recovery. The feeds, concentrates and tailings from rougher, cleaner and recleaner spirals in one mill line were sampled before and after the sizing screen openings were reduced from 2 mm to 1.6 mm. Sized fractions of each sample were analyzed with the MP-SEM-IPS image analysis system at CANMET to determine mineral quantities and liberation characteristics of the iron oxide minerals. Mass balance techniques were used to calculate stream recoveries of iron, silica, total iron oxide minerals, hema¬tite, goethite, quartz, ferromagnesian silicates, and liberated and locked total iron oxide minerals for each sieve fraction.The reduction of the sizing screen openings increased the ap¬parent liberation of the total iron oxide minerals in the screen undersize from 89% to 94% and raised the over-all iron recovery from 84.4% to 85.3%. Apparent liberation of iron oxide minerals in the cleaner sand also increased from 70% to 85%, but the – 75 µm fraction re¬mained the only fraction containing an acceptable amount of liber¬ated iron oxide minerals in each case. Due to limitations of spiral and grinding efficiency it is recommended that the cleaner sand be screened at 300 m, the +300 m fraction be reground, and the – 300 p.m fraction be rerouted to the rougher spirals.The amount of fine liberated iron oxide minerals (– 106 m) lost in the tailings was 46 TPH in mill line 3. This value represents 41 wt % of the free fine iron oxide minerals, or 7 wt % of the total iron oxide minerals in the spiral feed. Further work is needed to investigate the possibility of recovering this material by other methods.Middling iron particles (010 50%) and presumably free gangue in the size range –300+ 75 m tend to be recovered by spirals by entrapment."

Jan 1, 1990

By J. W. M. Porritt, K. C. Cheng

Knowledge of radon emanation rates from uranium-bearing rocks is essential to the design of mine ventilation systems for uranium mines. Measurements of equilibrium ratio between radon and its daughters in mine air are important for a better control of mine radiation conditions. The concentrations of radon and daughters were monitored at cut-and-fill stopes in the Beaverlodge Mine of Eldorado Nuclear Ltd. during all phases of the mining cycle. The radon emanation rates of ore and rock samples were measured at the laboratory and the results were compared with in-situ emanation tests in an isolated ore drift. Samples of backfill solution, backfill drainage and ground seepage water were measured [or radon and analyzed for radium and uranium. The results showed that discharges of backfill solution and daily shift-end blasts were the two major sources for a rapid release of radon gas in the ventilation air. Other mining operations, such as drilling, mucking, etc., contributed little effect on radon release to the mining environment. Radon emanation rates of the Beaverlodge are samples ranged from 13 x 10-18 to 600 X 10-18 Ci/cm2/ sec and that of waste rock samples from 0.54 x 10-18 to 13.4 X 10-18 Ci/cm2/sec. The in-situ emanation rate of mine walls with ore-to-rock ratios of 1 to 7 was 60 x 10-18 Ci/cm2/sec. The average equilibrium ratio of radon and its daughters in stapes was 32.6%. Under a normal ventilation condition, the average background levels of radon concentration in cut-and-fill stopes ranged from 13 to 80 pCi/L. The discharges of backfill solution during backfill operations at 100 tons solids per hour released approximately 1.8 x 106 pCi/min of radon and elevated radon concentration in stapes 2 to 5 times above the background levels.

Jan 1, 1981

By Joseph B. de Hart

Two papers recently published on the subject of mine ventilation: "The Theory of Ventilation," by Douglas Hay. and "The True Effect of Natural Ventilation in Deep Mines," by Robert Clive, form the first and second reports respectively of the committee on the Ventilation of Mines appointed by the Midland Institute of Mining Engineers. The purpose of the present paper is to draw attention to these two papers and the discussion thereon. The theory of ventilation as taught in our schools is based on Atkinson's formula, which is a variation of Chezy's formula for the flow of water in pipes. The formula depends on two assumptions : 1. That air is an incompressible fluid within the limits ordinarily encountered, and; 2. That the pressure required to produce ventilation varies as the square of the rate of flow. The Atkinson formula has been assumed to hold good over the entire range of conditions met with in mines.

Jan 1, 1924

By R. B. Roberts, A. L. Mular

A simple way to determine the IEP of oxide minerals is described. The method is shown to apply for fine powders of Fe203 and ZnO. The IEP lies at pH 6.95 for Fe203 and at pH 9.08 for ZnO.

Jan 1, 1966

By G. Wang, L. R. Moore, Y. Xiong, A. Gorken

"Mining is a very water intensive industry. As such, the industry has become dependent on applying alternate sources in efforts to minimize the impact on the locally available fresh water. Sources such as recycled water, sea water, and even acid mine drainage have been applied at some limited applications, while other mines may not even have the option of fresh water available in their region. However, the different sources of water will have varying concentrations and types of soluble salts and suspended solids, which can lead to dramatic differences in mineral processing when comparing these types of waters. Water quality is known to affect bubble generation and strength, mineral surface charge, and even reagent coordination properties. This paper focuses on the exploration of how water quality and soluble salts affect the flotation of iron and titanium containing minerals from feldspar, and the design of flotation collectors for optimal performance in this water.INTRODUCTIONFeldspar is defined as a tectosilicate mineral with the generic structure of MAlxSixO8, where M represents the cation (Celik, 2001). Feldspar is most often found naturally occurring with quartz, iron containing minerals (i.e mica), and titanium containing minerals (i.e. rutile). The alumina component of feldspar is of interest to glass making, while the alkali metal component is of interest to ceramics (Vidyadhar, 2002). In glass making, the alumina is known to improve product hardness, durability, and resistance to chemical corrosion. In ceramics, the alkalis act as a flux; a flux lowers the melting temperature of the mineral mixture, and assists in connecting the other components present in ceramics. Quartz is stated as having a negative effect on the melting point of the feldspar. Although quartz is typically not removed during the feldspar applications in the glass industry, it needs to be reduced for the ceramics industry. Iron and titanium based minerals are known to have negative effects on color and quality of the products in both glass and ceramics. Thus, these “contaminants” must be reduced to a certain product specification via feldspar beneficiation (Table 1)."

Jan 1, 2016

By D. Y. Kim

This paper shows an approach that a gondola-typed robot recognizes walls on building facades. It is applicable for autonomous or teleoperated building façade painting robots. The robot may react based on the wall classification data. This approach is based on 2D LRF(two-dimensional Laser Range Finder). The robot acquires relative distances to walls, and a Kalman filter decides correspondence of walls. An ARS(Attribute Reference System) sensor helps convert LRF coordinate to global coordinate. The experimental results demonstrate the conversion of LRF data.

Aug 1, 2013

By B. R. Schneiders

"Atikokan is 200 km west of Thunder Bay and earned its mining fame from the discovery of the Steep Rock Iron Range in the late 1930s. Gold, however, was discovered in the Atikokan and Mine Centre areas in the late 1800s and eventually led to one of Ontario's first gold camps, and a total production of approximately 52,000 oz of gold and 174,000 oz of silver from 218,000 tons milled.The general geology of the area consists of Early Precambrian rocks of the Wabigoon and Quetico subprovinces, separated by the east-trending Quetico Fault. The Wabigoon Subprovince, to the north, consists of metavolcanics, minor metasediments and granitic batholiths. The Quetico Subprovince consists of metasediments and granitoids. Small ultramafic plutons occur throughout the metasediments.Within a 50-km radius of Atikokan, more than 50 gold occurrences, prospects and past producers have been discovered since the 18oos. The Atikokan Gold Study performed by the Ontario Geological Sur vey (Wilkinson, 1980, 1982) defined three types of gold mineralization in which gold is concentrated in quartz and quartz-carbonate veins:I) Metavolcanic-Hosted, Stratabound Type-associated with altered felsic fragmental units and chemical sedimentary rocks; possible gold mineralization source rocks. The mineralization is due to metamorphogenic (epigenetic) enrichment. Associated with dynamic metamorphism events and/or felsic intrusive events.2) Marmion Lake Batholith Type-occurs within the gneissic core of the batholith associated with north east-trending lineaments, representing faults or shear zones. Mineralized veins are related to several periods of deformation and shearing, suggesting that metamorphogenic veins were produced during dynamic metamorphism.3) Contact Zone Type -occurs in the contact zone rocks between gneissic batholiths and meta volcanic belts. Hydrothermal solutions produced during several deformational periods acted to leach and concentrate gold mineralization. Localized, discontinuous shear zones host the epigenetic (metamorphogenic) veins.Twenty-one properties in the area were mapped and sampled, and researched petrographically and geochemically. Geological data from the Atikokan Economic Geologist Program of the Ontario Geological Survey are used in discussing the types of mineralization, genetic models, and exploration targets and techiques."

Jan 1, 1983

By Shahé Shnorhokian

Numerical modeling is increasingly being used as a tool to examine complex geomechanical issues related to rockmass behaviour and stability of underground openings. The in-situ stress regime and the evolution of mining-induced stresses during the life of an operation, taking into account the planned stope sequence, are topics that can only be handled through the use of a realistic and calibrated numerical model. This paper presents a case study of a deep underground Canadian mine in northern Ontario. A FLAC3D model was constructed and calibrated based on in-situ stress measurements. In the first stage, the evolution of stress regime was studied and compared with the occurrence of rockburst events during a period of three years. The locations of clusters were examined and compared to the mining sequence during that period. In the second stage, stresses within a diminishing ore pillar were examined based on the planned stope sequence and compared to levels deemed acceptable to the mine. Based on the results, an alternative sequence was arrived at to reduce stress accumulation in the pillar, or induce it to occur at a further distance from a brittle dyke in the vicinity of the orebody.

Aug 1, 2013

By R. Pakalnis, D. Tenney, B. Lang

"This paper describes three case histories whereby numerical methods were employed as a tool in the identification of potential instability. Simple two dimensional (PCBEM) and pseudo three-dimensional (BESOL, MINTAB) codes were employed to identify zones of induced stress which were subsequently related to extensometer, stress meter and observational data as the stope was excavated. The following case histories will be discussed. MacLellan Mine - sill pillar stability; Ruttan Mine-Hanging Wall Stability; and Detour Lake Mine-narrow vein mining.The MacLellan case history showed how modelling and instrumentation enabled mining to be conducted safely and under controlled conditions. MINTAB and PCBEM were employed to predict sill pillar failure. The sill pillar failure was associated, with an unloading of stress which was recorded by instrumentation (stress meter) and a decrease in the over-all rock mass strength. The yielded pillar, however, maintained its over-all configuration enabling access through the pillar.The Ruttan case history is an example of hangingwall and footwall design whereby the existence of adverse structure coupled with a zone of relaxation results in dilution. BESOL and PCBEM were employed to model a test stope and to verify the observations and measurements through instrumentation . Empirical methods of dilution estimates are employed to determine the level of walls lough with respect to the rock mass rating, stope dimensions and rate of excavation.The Detour Lake case history in an example of open stoping a narrow steeply dipping deposit. Stope dimensions are 135m in strike length, 47 m in vertical height with an average width (F/W to H/W) of3.6 m. Stress meters coupled with visual observations are related to modelled estimates of stress and dilution."

Jan 1, 1991

By A. B. Barlow, D. H. Pitcher

"The Geophysics/Geochemistry Section of the Ontario Geological Survey initiated an aerial geophysical survey in the James Bay Lowlands, Cretaceous Basin area, District of Cochrane, Ontario. The survey was contracted to Scintrex Limited and was carried out in 1978. Approximately 8000 line kilometres of airborne electromagnetic and magnetic data were recorded. The Tridem airborne electromagnetic system was employed, mounted in a twin-engined PB Y Canso aircraft. This specific Tridem system uses a vertical coaxial coil configuration and measures in-phase and quadrature components of the secondary field at 500, 2000 and 8000 Hz.The primary purpose of this survey was to map subsurface conductivities and, in particular, to search for lignite deposits. Physical property measurements show that electrical methods should detect differen ces in conductivity between the moderately conducting clay-lignite horizons and the less conducting clay, soil, muskeg and gravel horizons. A preliminary Tridem test survey, as well as surface DC resistivity soundings, confirmed this approach. The interpretation of the present survey data indicates that Tridem is a suitable electrical method to aid lignite exploration in the James Bay Lowlands."

Jan 1, 1980

By Denni Nikols, Farrukh Z. Khan

"Highvale Mine, located at Wabamun, Alberta, produces thermal coal for TransAIta's Keephills and Sundance generating plants. Overburden stripping in the mine is conducted by draglines which normally operate on top of the overburden bench. In certain areas oj the mine, however, these overburden benches are susceptible to slope failure. In these areas, due to safety considerations, the draglines are utilized in the less productive chop-cutting mode, supplemented by mobile equipment where the bench height exceeds the dragline chop-cutting limit. This paper proposes maintaining the draglines in their normal digging mode through areas of unstable or jailed overburden, by utilizing a dragline carried toe buttress 10 ensure adequate bench stability. The data requirements and methods of slope analysis to design a toe buttress across an unstable highwall area are examined in rigorous detail. INTRODUCTIONLocationHighvale Mine is owned by TransAlta Utilities Corporation and operated under contract. It is Canada's largest coal mine with an annual coal production in excess of II million tonnes. The mine is located approximately 80 km west of Edmonton on the south shore of Wabamum Lake (Fig. I) and production is currently provided by three pits 02. 03 and 04 (Fig. 2). The entire coal production is consumed at the nearby Sundance and Keephills power generating plants.ScopeThe mining operation at Highvale Mine has had occasional slope stability failures of its high wall overburden bench. This paper examines one such failure which occurred in the summer of 1983 at Pit 03. In addition to an investigation of the failure, Terracon was asked to recommend mine operation procedures which would minimize the impact of these slide zones on dragline productivity. A method of removing the failed material by utilizing the dragline in its normal digging mode is designed. The method's advantages and disadvantages as well as the required support procedures are reviewed."

Jan 1, 1989

By Ernest A. Hodgson

WHEN excavations are made, at depth, in hard brittle rock structures, as in certain mines in India, in South Africa, and in Ontario, the pressure due to overburden, together perhaps with inherent geologic strain, tends to become concentrated in the walls of some of these openings and the rock bursts, often closing the adjacent drifts and scopes and presenting a serious menace to the miners. Where the rock is much fractured and faulted, the danger is greater, since the pressures tend to shift without warning from point to point, sometimes within a few hours. Attempts have been repeatedly made to find some physical property of the rock which will change with pressure, which can be measured for rock 'in place' in the mine, and which will give an indication of the state of strain, thus warning of an approach to bursting conditions. Some of the properties tested have been the speed of propagation of elastic waves in the suspect rock, variations in temperature due to pressure changes, rate of closure of openings or shifts along fault planes, strain gauge measures, and others. Each of these has proved unsatisfactory for the purpose. The most promising method so far proposed has been the study of the very faint, sub-audible snaps (microseismims) which are produced in rocks under pressure. Such a study has been in progress at Lake Shore Mines since May, 1942. Instruments designed to pick up, amplify, and record the microseismims were perfected and a programme of observing, using the microseismic method, has been carried through with persistent diligence and at considerable expense. In 1943, experience with the method in a pillar section on the west side of the Lake Shore mine gave much promise of predicting bursts. A very heavy burst on January 29th of that year occurred in the exact section of the mine covered by the instruments, and the records indicated a measure of prediction. In response to repeated requests for information, a number of reports were given out, among others a radio talk by the writer over CJKL (Kirkland Lake), which was reported in full in the Northern News . Also, a detailed account of the occurrence was given in an illustrated paper by the writer (l).

Jan 1, 1945

By P. B. Marchant

"Considerable gold and silver values are lost to flotation tailing from both the South ern Tail orebody and the Main Zone orebody,The underlying mineralogical assemblage of the two ore types is quite different. This paper describes the research strategy employed to determine an economical method to scavenge gold and silver from flotation tailing.Much of the unrecovered gold in the Southern Tail ore is associated with arsenopyrite while silver losses are probably as unliberated tetrahedrite and minor silver-bearing sulphosalts. Processing alternatives tested include bulk sulphide recovery by flotation and gravity, selective pyrite-arsenopyrite separation, cyanidation, and oxidation pretreatments such as pressure leaching and bioleaching to enhance cyanidation response. Gold losses in the Main Zone ore are more closely associated with silver-bearing minerals, pyrite, and siliceous gangue and consequently respond more readily to conventional tank cyanidation. The 5 300 tid carbon-in-leach circuit to treat Main Zone flotation tailing is described in detail.IntroductionEquity Silver Mines Limited's open-pit silver mine, a 70% owned subsidiary of Placer Development Limited, is located 37 km southeast of Houston in north central British Columbia. The deposit consists of two major ore zones, Main Zone and Southern Tail (Fig. I). These zones are within a sequence of Cretaceous volcanic and sedimentary rocks striking 015 degree s and dipping 45 degrees west. Feasibility ore reserves were 28 million tonnes grading 106 g A g/t, 0.96 g Au !t and 0.38% Cu a strip ratio of 2.2 to I. A detailed mineralogical description has been presented and a comparison of the two ore zones is shown in Table I."

Jan 1, 1986

By I. R. Muirhead

"One approach to making new technology available is to demonstrate its value under full-scale operating conditions. Studies were undertaken to assess the feasibility of this approach to introducing a longwall mining system to the western Canadian coalfields.The longwall method of mining coal is described, world and Canadian usage is reviewed, and the merits of the system in comparison 10 other coal mining methods are discussed.The rationale for a longwall demonstration in western Canada is presented, along with a proposed organization for the design, operation and dissemination of the findings from such a trial. The factors which must be considered in the design of the demonstration, and in the assessment of a potential site are highlighted. It is concluded that a demonstration of this technology is both timely and essential to prepare the way for the western Canadian coal industry of future prospects for coal.IntroductionFor many years CANMET has encouraged research work organized on a cooperative basis. This requires that a working consensus must be negotiated by researchers and operators at the beginning of the project and continuously refined as work proceeds. The result is usually a more relevant selection of research problems, improved direct ion and con duct of experiment al work and often a validation phase in which research concepts are tested in an opera ting environment. All this tends to narrow the gap between obtaining research results and applying them.Even under the best of circumstances cooperative projects require a good deal of coordination and enthusiasm to maintain focus and the pace of work. The working perspective of a research scientist in a government laboratory is substantially different from that of a mine operator at a producing mine, and a common ground must be found. This is difficult to do and cooperative projects typically evolve over several years as experimental results progressively define the potential solutions to mining problems."

Jan 1, 1985

By V. S. Papezik

Pyrophyllite, a hydrous aluminium silicate, is used mainly in the ceramic industry and to a lesser extent as a filler in the manufacture of paper, rubber, insecticides and baby powders. Commercial deposits of pyrophyllite in North America are restricted to the "Avalon Zone" , a belt of late Precambrian volcanic and sedimentary rocks that extends along the eastern flank of the Appalachian orogenic belt f rom Georgia to Newfoundland. The only commercial Canadian pyrophyllite deposit lies near Foxtrap on the A valon Peninsula of Newfoundland. Here, steeply dipping lenses of altered pyrophyllite rock occur in a north-trending rhyolite belt near the contact with a granitoid pluton. The altered rock is massive, light greenishyellow and contains varying proportions of pyrophyllite, sericite and quartz with lesser amounts of diaspore and traces of barite and rutile. A lteration was produced by acid solutions, either derived from or activated by the intruding pluton, at temperatures of 250° to 270°C and pressures not exceeding 2 kbr. The largest of the Foxtrap pyrophyllite lenses, discovered in 1897, was mined intermittently f rom 1903 until the early 1950s. The present owner of the mine, Newfoundland Minerals Limited, acquired the property in 1959 and ships between 27, 000 and 36,000 tonnes annually to th e company plant in Lansdale, Pennsylvania, for use in ceramic tile.

Jan 1, 1984

By J. P. Messervey

As a result of my field examinations in this Province, I have been struck by the evidence of widespread mineralization in rocks, particularly the limestones of Carboniferous age. Six prospects of lead and zinc or lead alone scattered through the eastern part of the mainland, one copper prospect and three veins of siderite, all point to a period of mineralization subsequent to the forming of the Carboniferous rocks in which they occur. While none of the present prospects are of proved economic importance, still it is possible, and indeed probable, that further prospecting will find concentrations sufficiently large to make mines. It may possibly aid the prospecting for these base metals if the present scraps of information are assembled from various sources, and I will further briefly recount the information as a result of my observations. Gay?s River At Gay's river, midway between Halifax and Truro, and four miles east of the railway, numerous pits and natural exposures show galena and sphalerite in limestone of Carboniferous age, near where it lies unconformably upon slate and quartzite of the gold series. These exposures extend for a length of over one thousand feet along a curving contact. The pits show that on the contact there is a fossiliferous and somewhat porous layer of limestone, which is so impregnated with galena and small amounts of sphalerite as to be of ore grade. Wherever observed, the thickness of this layer is less than two feet.

Jan 1, 1929

By N. Kacira

"Canada's largest known chromite deposit occurs in a layered intrusion in the Bird River area of Manitoba. However, numerically most of the chromite occurrences are in the Appalachians. Few, apparently minor, occurrences are also known in the Cordillera.In the Appalachians, chromite occurs as lenses and pods in dunite; they are of ""podiform"" type. The individual concentrations vary in size from a few pounds to tens of thousands of tons. Locally, chromite concentrations form discontinuous zones extending several hundred feet along strike and presumably down dip, therefore resembling boudinaged layers. Chromite layering and lineation are commonly concordant to those of the host rocks.The Appalachian chromite occurrences are thought to have been formed by fractional crystallization and perhaps also by liquid immiscibility. Their present shape and distribution are largely the result of deformation mostly prior to complete solidification of their host rocks. Therefore, the attitude of layering, foliation, lineation and other features related to deformation provide valuable guides in predicting the probable distribution of chromite, and hence are helpful in exploration.Chromites fulfilling the requirements for metallurgical, refractory and chemical grades occur in the Appalachians. Although the Appalachian deposits are similar in size and grade to some of the chromite deposits being mined elsewhere, they are unlikely to be economic, at present, in the higher wage Canadian environment. However, in case of shortages in chromite ore supply which may result, among other reasons, from increasing tendency to further processing in the producing countries, the Appalachian occurrences may become sources of ore. Such eventual shortages combined with relative abundance of electricity in Canada and recent innovations in oxide ore reduction technology may hasten the time when ferrochrome manufacture based on local chromite sources becomes economically viable."

Jan 1, 1982

By L. T. Raevskaia

We discuss the stability problem of a piston of the reversible axial-piston pneumatic motor called DAR-14M. We performed the full analysis of stress and deformation characteristics of the piston near a resonant frequency with the help of FEM ANSYS. We estimated the own frequency of the piston analytically for the given motor, this estimate was confirmed numerically in the model analysis FEM ANSYS. It was also shown in harmonic analysis that loaded piston end behaves very different in comparison to the unloaded end. As expected, maximum deformation was found in the area of the holes of the bearing shaft, indicating an optimization necessary in that region of the motor.

Aug 1, 2013