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By W. T. Martson

ABSTRACT Sooner or later, every producing mine faces the question of fill. This paper invites consideration of mill tailings as an economical, efficient, and quantitatively adequate source of such fill. Some of the advantages, disadvantages, methods of utilization, and methods of treating mill tailings for sand recovery are covered. ADVANTAGES AND DISADVANTAGES OF SAND FILL DISREGARDING economic com-promise, that material which supports the greatest applied load with the least compression is the best choice for fill. Table I, reproduced from U. S. Bureau of Mines Bulletin 60, is offered as evidence of the adequacy of hydraulically placed sand. Table II gives the results of tests made in an effort to determine the reason for the difference between load hearing qualities of dry-placed and hydraulically-placed sand. From these, it would appear that hydraulic placing gives a denser initial packing, with corresponding higher, and faster development of, load bearing qualities. Assuming this to be true, then if sand from mill tailings can be placed underground economically, it is the superior fill material. Table III summarizes cost data available. The most cursory glance through the available references (2, 5, 6, 7, 8, 9) will show .that the major benefit from the adoption of sand fill is a decrease in the non-productive fill ?cycle of a working place. This, it is estimated, increases the output of an individual stope by from 25 to 50 per cent. The advantage of reducing the number of required working places for a constant daily production is obvious.

Jan 1, 1951

By Limao Zhang

This paper presents a novel model to assess the risk of adjacent buildings in tunnelling environments based on Extended Cloud Model (ECM). ECM is an organic integration of Extension Theory (ET) and Cloud Model (CM), where ET is appropriately employed to flexibly expand the variable range from [0, 1] to (-8, +8), and CM is used to overcome the randomness and fuzziness during the gradation of evaluation factors. The risk level of a specific adjacent building is assessed by the correlation with the cloud models. A confidence indicator ? is proposed to illustrate the rationality and reliability of evaluating results. Ten buildings adjacent to Wuhan Metro Line Two (WMLT) are randomly chosen among hundreds of adjacent buildings for a case study. Results have proved to be consistent with the actual situation. Compared with other traditional evaluation methods, ECM has been verified to be a more competitive solution with high calculation accuracy, wide adaptability, as well as simplified computer programming. There are no stringent requirements on the quantity of training data during the modelling process, and the original data can be directly entered into ECM without a normalization procedure, avoiding the potential information loss. ECM can be offered as a decision support tool for the risk assessment in urban tunnelling construction and worth popularizing in other similar complicated projects.

Aug 1, 2013

By Veerendra Singh, Y. Rama Murthy, Sunil Kumar Tripathy, Nikkam Suresh

"High intensity dry magnetic separation is commonly employed to separate different para-magnetic minerals including mineral sand. Separation in these separators is majorly influenced by the combined effect of gravity, centrifugal and magnetic forces on a particle. These separators are included in the process flow-sheets either for pre-concentration purposes or for the beneficiation of paramagnetic minerals. Separation in these separators is majorly influenced by the difference in the magnetic susceptibility of the associated minerals, particle size and shape along with the process variables of the machine. Particle size is one of the major parameter that plays an important role and decides its probability of selectivity under the magnetic field. However, effect of particle size on the performance of these separators are not well understood which is evident from the literature.In the present investigation, an effort is made to bring out the effect of particle size on particle separation in an induced roll magnetic separator while treating ilmenite fines. Effects of operating parameters, such as; magnetic field intensity, roll speed, feed rate and splitter position have been studied and their influence on particle size has been analysed in terms of yield (wt.%) to magnetic product, particle size distribution characteristics in terms of D50 and D80 size, skewness, kurtosis. Also, the particle size distribution of each test was fitted in Rosin-Rammler equation. The test results were analysed statistically to understand and quantify the influence of each variable on particle separation. It is found that, rotor speed of the separator had maximum influence on yield to the magnetic product whereas splitter position had major influence on D50 and D80 (µm) size of the product."

Jan 1, 2016

By R. Pandher, R. Schonewille, N. Tripathi

Advanced process modelling tools were developed for the Xstrata Nickel Sudbury Smelter flow sheet using a combination of FACTSAGE TM METSIMTM and ARENATM software. These tools were employed to assist with plant optimisation, emission control, process design, troubleshooting and case studies as applied to the smelter. The development of process modelling tools in pyro-metallurgy commonly involves an in-depth study of the therm o-chemical properties (heat capacity, liquidus temperature, etc.) of all high temperature phases, usually matte and slag. The preferred tool for this purpose is FACTSAGETM, a well-known then-no-chemical modelling software package. The results from the therm o-chemical model have been subsequently incorporated into the development of a process model for the entire smelting facility using the METSIMTM platform. Such process model also includes a number of special features adopted to effectively simulate the complex industrial phases; matte and slag systems. To ensure the robustness and reliability of the process model, several process parameters and assumptions were verified with laboratory and plant data. Consequently, the model includes the ability to examine the impact of a number of plant parameters on potential plant performance. Primary variables are the percent sulphur elimination during concentrate roasting, furnace matte grade and degree of matte metallization. Key output parameters include operating temperature, furnace coke requirement, sulphuric acid production, CO2 emissions and overall energy requirements. Selected outputs from the process model (for example blowing time, slag production rate and matte converting rate) can then be utilised in the development of a discrete event model (DEM) for the smelter using ARENATM software. Incorporation of reliable and validated mass balance parameters enhances the robustness and reliability of the DEM model. The integration of then-no-chemical, process and DEM modeling tools has a distinct advantage in planning plant trials and examining process design initiatives at Xstrata Nickel's Sudbury Smelter. The present paper discusses the development of these three models and the synergies existing among them. Typical results from all three models are also presented.

Jan 1, 2011

By Richard R. Walker, John J. Watkins, Allen C. Amos, Matulich. Angelo

THE KIDD CREEK MINE is located within the Abitibi greenstone belt, near its west end, in an area known as the Porcupine mining camp (Fig. 5). The Abitibi belt, long known for its many major gold and base metal deposits, is the largest Archean (early Precambrian) greenstone belt within the Canadian Shield. In the Porcupine area, the greenstone belt is composed principally of Keewatin (older Archean) basic to intermediate volcanics, with subordinate felsic volcanics developed• locally. Greywacke, mainly of volcanic derivation, occurs associated with and overlying these volcanics. Timiskaming (younger Archean) sediments, principally coarse clastics, unconformably overlie the Keewatin volcanics and sediments. The reader is referred to Goodwin and Ridler (1970) •r. for a more comprehensive description of the Abitibi belt.

Jan 1, 1974

By F. A. Forward

Introduction The main line of ascent in the development of the nickel industry may be traced back through the International Nickel Company of Canada, Limited, to its earliest antecedents, the Canadian Copper Company and the Orford Copper Company. Mining geology is but one aspect of the overall development of this organization, and the stress it has placed on geology grew according to the need. In the early days, intensive geology was not required because ore supply was not one of the main problems of this or any of the pioneer companies. The difficulty then was to find economic methods for reducing the ores to nickel and copper, and markets for absorbing nickel in the face of a limited demand from consumers heavily prejudiced in favour of the New Caledonia product. "Very early in the history of the region it was patent to everyone that to share in the full benefits of the industry the same individuals or company must control the whole of the operation necessary to manufacture the finished product' (1, p. 45). These conditions were fulfilled for the International Nickel Company in 1902 when the Canadian Copper Company (incorporated 1886), with its ample ore supply, took the initiative to merge its interests with those of the Orford Copper (Refining) Company (incorporated 1887) to form the new company which, with reorganizational changes, emerged as the producer of the overwhelming bulk of the world's nickel. The Mond Nickel Company, Limited, entered the field in 1899 with a refining process, and over a period of years acquired ore through purchase of mining properties. This Company operated successfully and independently until 1929 when its assets were joined with those of the International Nickel Company in order to permit the most economic exploitation of the Frood-Stobie orebody in which both Companies were interested.

Jan 1, 1948

By R. Pandher, R. Schonewille

Advanced process modelling tools were developed for the Xstrata Nickel Sudbury Smelter flow sheet using a combination of FACTSAGETH METSIMTM and ARENATM software. These tools were employed to assist with plant optimisation, emission control, process design, troubleshooting and case studies as applied to the smelter. The development of process modelling tools in pyro-metallurgy commonly involves an in-depth study of the therm o-chemical properties (heat capacity, liquidus temperature, etc.) of all high temperature phases, usually matte and slag. The preferred tool for this purpose is FACTSAGETM, a well-known then-no-chemical modelling software package. The results from the therm o-chemical model have been subsequently incorporated into the development of a process model for the entire smelting facility using the METSIMTM platform. Such process model also includes a number of special features adopted to effectively simulate the complex industrial phases; matte and slag systems. To ensure the robustness and reliability of the process model, several process parameters and assumptions were verified with laboratory and plant data. Consequently, the model includes the ability to examine the impact of a number of plant parameters on potential plant performance. Primary variables are the percent sulphur elimination during concentrate roasting, furnace matte grade and degree of matte metallization. Key output parameters include operating temperature, furnace coke requirement, sulphuric acid production, CO2 emissions and overall energy requirements. Selected outputs from the process model (for example blowing time, slag production rate and matte converting rate) can then be utilised in the development of a discrete event model (DEM) for the smelter using ARENATM software. Incorporation of reliable and validated mass balance parameters enhances the robustness and reliability of the DEM model. The integration of then-no-chemical, process and DEM modeling tools has a distinct advantage in planning plant trials and examining process design initiatives at Xstrata Nickel's Sudbury Smelter. The present paper discusses the development of these three models and the synergies existing among them. Typical results from all three models are also presented.

Jan 1, 2011

By D. B. Smith

DURING the summer of 1953, test work commenced at the Sullivan Concentrator with a view to the modification of filtration practice by the inclusion of wet cyclone classification of the lead concentrates, with separate filtration of the underflow and overflow products. Formerly, practice was conventional and the equipment employed comprised one 50-foot diameter thickener ?with the underflow routed via a 20-foot stock tank to two 8-foot by 12-foot Oliver filters. Heating of the filter feeds to 40° C. and the use of mechanical slappers on the filter drums ?have both been standard features of Sullivan practice for years. Both of these have been retained. Currently (February, 1956), lead concentrates are being classified into sands and slimes by 12-inch cyclones with the underflow, at 75 per cent solids, being fed to No. 1 Oliver filter. The overflow is thickened to 75 per cent solids and filtered separately by a No. 2 Oliver filter . The tonnage split is approximately two of underflow to one of overflow. The overflow contains 75 to 80 per cent of the total minus I 500 mesh slimes in the feed.

Jan 1, 1956

By S. Y. Ezz, K. El•Guindi

A vertical tube, 8 m long and 2.5 cm in diameter, electrically heated to 650°C throughout the majority of its height, was used to study the-effect of ore feed rate and hydrogen flow rate on the reduction of fine iron ore particles. A correlation could be obtained between the combined effect of the amount of reducing gas and reduction time and the per-cent reduction. The results suggest that a method based on the reduction of fine iron ores while falling through up-streaming hydrogen cannot be recommended for industrial application.

Jan 1, 1969

"Under the term ""paleogeomorphology"" are grouped together all geo-morphological phenomena which are recognizable in subsurface geology. Since geomorphology is the science of the earth's relief features, paleogeomorphology is the science of buried relief features. Such features are of importance to the petroleum geologist whenever they lead to the trapping of hydrocarbons. In areas where these features abound -and western Canada certainly is such an area -pale-ogeomorphology ranks in importance with stratigraphy and structural geology as a hydrocarbon-finding tool. Hydrocarbons may be trapped either directly or indirectly due to paleogeomorphological processes. Both types of traps may occur either below the morphological surface or above (against) it. Several examples of types of paleogeomorphological traps are given. A new classification of geomorphological .features is proposed, with a subdivision into two main groups: constructive and destructive geomorphic processes. Of the many geomorphic classifications, some are of greater interest to the petroleum geologist in western -Canada than others. In the present paper the morphology of reefs and of buried erosional land forms are discussed in greater detail. In dealing with the reefs of the Devonian Leduc formation in Alberta, it is found that several groups of reefs can be distinguished and that each group presents a separate set of morphological characteristics. The effects of erosion and weathering are exemplified mostly in the Devonian, Mississippian and Jurassic of Alberta, Saskatchewan and Manitoba. Hydrocarbon traps occur below the highs on the erosional surface as well as in sands laid down in the lows of that surface. The rules which govern the formation of ancient landscape forms are worked out, using an area in southeastern Saskatchewan as an example."

Jan 1, 1960

By G. Van Weert, O. Wang

"As part of a general review of processing double refractory ores through Barrick Gold’s autoclaves / CIL facility at Goldstrike, blanking the preg robbing native carbon in the process solids with hard (m.p. 55 - 60 º C) paraffin wax was studied, specifically in relation to pressure oxidation. The improvement in CIL gold extraction was found to depend on the wax addition point, with hot, dry contacting of the ore in the presence of wax - prior to POX - yielding the largest, most consistent improvement in gold extraction.INTRODUCTIONDouble refractory gold ores present two barriers to gold extraction. The first is generally a physical barrier: the gold is encapsulated or dispersed in a matrix which is impervious to the gold lixiviant. In most cases, including Carlin Trend, NV, deposits, this involves a pyrite or arsenopyrite matrix, although minor gold may also be dispersed in competent silica (quartz) or iron oxides. Gold can be rendered accessible by oxidative destruction of such sulphide matrices. At Goldstrike this is practised by roasting and autoclave oxidation (Thomas, 1994). It is the latter route to which this paper refers.The second barrier refers to the actual gold recovery. Gold may be extracted from the pressure oxidized solids with cyanide, forming a gold cyanide complex. One characteristic of this complex is that it adsorbs on graphitic surfaces. This is taken advantage of on a large scale by gold millers, who use manmade activated, i.e., graphitized carbon particles to remove the gold from solution during leaching: the Carbon-In-Leach, or CIL process. The gold cyanide bearing carbon particles are larger than the ore solids and can be separately recovered by screening. Goldstrike uses the CIL technology to recover gold. The second barrier becomes problematic when the ore naturally contains graphitic orcarbonaceous material, hereafter referred to as native carbon (versus the man-made activated carbon). This material may also adsorb gold cyanide in competition with the activated carbon. Since the native carbon is ground with the ore it is much smaller than the activated carbon. Any competition between the two carbons may produce a loss of gold from the pregnant leach liquor to the process tailings. This phenomenon is called “preg robbing”. Goldstrike ores come from the Carlin trend, which is known for the occurrence of native carbon (Adams & Burger, 1998; Schmitz, Duyvesteyn, Johnson, Enloe & McMullen, 2001; Tretbar, 2004)."

Jan 1, 2012

By F. D. Ball, D. E. Gemmell

"Coal mining in New Brunswick dates from the year 1639, when, as today, coal was produced from the area surrounding Grand Lake near the geographic centre of the province. Current production by N.B. Coal Ltd. is approximately 453,000 tonnes per year and comes from a single, thin Pennsylvanian age seam. The history of development and understanding of the geological setting of New Brunswick coals is discussed, beginning with the work of A. Gesner in 1839. The lithostratigraphic sub-divisions of the Pennsylvanian strata proposed by various workers are summarized and the present hypothesis that only biostratigraphic subdivision is possible is detailed. The Pictou Group, which includes the New Brunswick coals, consists of repetitive sequences of sediments consistent with flu vial and upper delta plain sedimentation. The development of coal mining in the province has progressed from horse-powered stream-bank stripping operations prior to the late 1800s through to the present use of open stripmining techniques utilizing eight walking draglines of various sizes. During the intervening years the introduction and eventual phasing out of underground mining occurred with the near termination of the coal mining industry in the province prior to 1973. The coal seam worked by N.B. Coal Ltd. averages 46 cm in thickness, has never been found to be more than 76 cm thick and has both high ash (12.4 -31.1%) and sulphur (4.9-7.8%) content. The wide variety of coal beneficiation studies and tests completed on New Brunswick coals have lead to the conclusion that a washed New Brunswick coal product could be expected with 10 to 12% ash, 5 to 6% sulphur, and 30,225 to 31,388 1/gm. Recoverable coal reserves, including those in the area licenced to N.B. Coal Ltd. and those licenced, although not yet in production, to both the St. Lawrence Cement Co. Ltd. and Provincial Holdings Ltd. at Lake Stream and Beersvil/e, total 60 million tonnes. At present, coal in New Brunswick is removed from prospecting and staking and all existing and future coal exploration and development will be administered by agreement under the Mining Act. Based on the results of a recently completed drilling project undertaken by the Department of Natural Resources, seventeen coal exploration blocks which carry minimum work commitments will be offered to the New Brunswick Electric Power Commission on a sixty-day first right ofrefusal basis. Those blocks not taken up by the Power Commission will be offered under the same commitments to the private sector."

Jan 1, 1985

By J. E. Hawley

Abstract Spectrographic methods for the analysis of minor constituents such as platinum-group metals, gold, silver, and silica in palladium and platinum refinery sponge are described. These involve the conversion of the sponge metals to the black form by reduction with high purity aluminum filings in either acid or alkaline media. Standards of known composition are prepared in the same manner from either refinery or spectrographically standardized sponge metals. Samples of the black metals are mounted in pellet form and a multisource spark discharge used for excitation. The range of concentrations of impurities studied are those common to refinery samples. Excellent reproducibility of intensity ratios using major constituents as internal standards, is demonstrated and two methods have noted by which the accuracy of the procedures are shown to be of the order of 3 per cent, on the basis of synthetic preparations. Introduction During the past two years an investigation has been carried out in the Spectrographic Laboratory, Queen's University, to determine the suitability of modern spectrographic techniques for the precise analysis of the platinum-group metals palladium, platinum, rhodium, iridium, and ruthenium in the form of refinery sponge analyzing about 99 per cent of the major constituent.

Jan 1, 1951

By D. W. Tully

Sedimentary and volcanic rocks of the Timiskaming series trend west-ward across the property of the Upper Canada mine, forming part of the north limb of a regional syncline which is truncated on the south by the Larder Lake fault zone. A wide zone of schistosity strikes east-west through the sediments and volcanics. The central portion of this zone is occupied by a system of narrow gouge-filled fractures in highly altered rocks, mainly tuff, trachyte, trachyte porphyry and syenite porphyry. The alteration zones have developed through repeated stages of deformation and accompanying metamorphism. The initial stages were marked by carbonatization and sericitization, followed by silicification and the introduction of minor amounts of sulphide minerals. Gold was finally de-posited in relatively late fractures within silicified zones and pyrite. Repeated movements along the Up-per Canada break have offset post-ore dykes of minette and diabase, and have resulted in minor displacements within the orebodies.

Jan 1, 1963

By H. Rozovsky

"AbstractThis paper discusses the methods of handling air in a large asbestos mill presently being completed at the Jeffrey mine of the Canadian Johns-Manville Company in Asbestos, Quebec.The mill, being the largest single asbestos producer in the world and capable of handling over 14,000 tons of ore per day, requires vast quantities of air. A minimum of 2,500.000 c.f.m. is required or about 10 tons of air for each ton of ore milled.Short descriptions of the process and systems requiring this air are given, followed by details of the fans and filters which make up the heart of the mill.This 'draw through' system, located on the top or 12th floor, is an automatically .controlled volume-pressure system creating the required suction to draw .air throughout the mill building and its numerous air systems.The dry mechanical method of milling develops enormous quantities of airborne dust and fibre. A section of this paper is devoted to a description of the multiplicity of dust systems within a system to control, filter, and remove this dust.Finally, the paper describes the method of returning the filtered air to the• working floors or to the outside, with some notes on heat, humidity and dust counts.IntroductionGeneralTHE discussions in this paper deal only with operations where air movement is involved. No attempt is made to delve into production methods.The Jeffrey mine of the Canadian Johns-Manville Company, located about 100 miles east of Montreal, is the largest single asbestos producer in the world, being responsible for over half of Canadian asbestos fibre production."

Jan 1, 1955

By E. Swartzman

This paper presents a general re-view of the various methods of briquetting coals, with and without the aid of a binder, with special reference to the production of a suitable briquette from Nova Scotia 'fines' for re-blending with industrial coal. From the economic and technical viewpoints, either small stoker-sized briquettes made with about 4 per cent asphalt in standard low-pressure double-roll presses, or briquettes made without binder in high-pressure double-roll presses, appear to be the most reasonable solution at present.

Jan 1, 1959

By Robert B. Parsons

"The 1994 Quebec Budget included a significant overhaul of the mining duties sys-tem in that province: broadening the base and lowering the rate, all in the name of “ensuring the integrity of the taxation system"" and ""enabling the State to collect fair compensation "". The reforms hit hardest on the small, lightly-capitalized producer, by repealing the basic annual exemption, limiting the refund for losses, and significantly reducing the investment and processing allowances. There is some relief provided in the form of faster depreciation rates and a lower nominal tax rate, but the thrust of the overhaul is clear -higher taxes on the mining sector.IntroductionAlthough Quebec's mining tax regime represents under 10J0 of the province's revenue base, and was significantly reformed in 1979 and 1985, the May 13, 1994, provincial budget introduced further significant changes to the Mining Duties Act, The hope (on the part of the province) is to reduce the provincial ""subsidy"" for mining by $20 mil· lion per year by 1996."

Jan 1, 1995

By Adrian Dance

Barrick Gold Corporation?s wholly owned subsidiary, Barrick (Granny Smith) Pty. Ltd. operates the Granny Smith operation in Western Australia and has been operating a SAG/ball mill (SABC) circuit for a number of years processing a blend of secondary crushed, open pit and underground material. With closure of the open pit in 2008, Granny Smith was considering different options to process underground only material at a lower throughput. Using the existing equipment available on site, a number of circuits were evaluated by Metso Process Technology & Innovation (PTI) through modelling and simulation. A single stage SAG mill circuit was selected based on power requirements and operating efficiency. In April 2008, Granny Smith started operating their SAG mill in single stage, processing primary crushed feed and using their existing pebble crusher for scats. Smaller cyclones were used to control the final grind size. PTI surveyed the new single stage circuit in July 2008 under normal and high rock load conditions to show the effect on final grind size. Granny Smith continued to operate this circuit until the end of 2009, when alternate feed sources resulted in a return to the complete SABC circuit at a higher tonnage once again. The variable speed, single stage SAG mill proved itself to be very efficient and flexible option to process the hard underground Wallaby Deeps material. This paper will review circuit performance following the conversion to single stage in comparison with the full SABC circuit.

Jan 1, 2012

By Saravarim A.

"The aim in flotation systems is to control the grade and recovery of the product., numerical method or sampling and analysis is used to achieve this goal. Weakness of measuring instruments, lack of process knowledge, deficiencies in management and data processing in the control of flotation cells, has led the academic and industrial units to use numerical models. In this regard, using the results obtained from the experimental design carried out in the DTP line of Gol Gohar industrial and mining complex, a regression model was developed based on the analysis of variance. To present this model, after variance analysis of factors and interactions, all models were investigated and the final model was created based on 75% of the data. The model was tested with the remaining 25% of the data to confirm the goodness of the fit. The coefficient of determination for training and testing resulted 71% and 74%. Moreover, a feed forward back propagation neural network with different layers and neuron was used to model the results. The best network structure was 6-27-1 and the coefficient of determination for this network was 99% and 98% for training and test respectively. Given the complexity of neural network models and the relatively low accuracy of the regression model, neural network has a priority assuming we have access to a specialist. In addition, the results obtained from neural network can be used as expert systems to control and optimize the flotation cells.INTRODUCTIONThe primary objective of the flotation cell control is to maintain the product's (in this case tailing) recovery and grade, which represents the index for process efficiency and product quality. Continuous estimation of these indexes requires a significant amount of maintenance, and calibration of the continuous analyzers, in order to maintain an acceptable level of accuracy. Weakness of measurement equipment, lack of process knowledge and the general deficiency in management and processing of data in the flotation cell control, will lead industrial units to use smart methods such as mathematical models, regression and neural networks in near future (Panahi, Abdollahzadeh, & Sam, 2010). Artificial neural networks are inspired by the very complex structure of human brain in which millions of nerve cells solve problems or store information by communicating with each other. The duty of neural networks learning. It should be noted that learning in artificial neural networks is limited, and what is practically considered is the computing power of the network. A neural network consists of units called neurons, and has the capacity to handle a set of input data to produce a desired output data set. Each of these input and output data sets can be assumed as a vector (Soltanmohammadi & Noparast, 2006)."

Jan 1, 2016

By Nav Dhadli

Tailings from Oil Sands MiningWhat are they? Challenges Solutions Regulatory Environment Definition of the AFD Tailings Treatment Process 2010 AFD Pilot/Demonstration ProgramTechnical challenges Performance and Results Next steps Oil Sands Industry Collaboration on Tailings Technology TAILINGS ?WHAT ARE THEY? Mixture of remaining water and solids following bitumen extraction process Composed of water, sand, silt, clay, small amounts of hydrocarbon (bitumen, solvent, and asphaltenes) A necessary part of production in excavation of oil sands and removal of bitumen

May 1, 2011