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By Gordon G. Duncan

Historical Sketch Occurrences of native copper have been known along the Arctic coast of Canada, especially in the vicinity of the. Coppermine river, since the early part of the eighteenth century (See map, Figure 2, insert). In 1769, Samuel Hearne, a clerk of the Hudson's Bay Company at Fort Churchill, was sent to explore the 'copper mines' from which natives had been reported to secure copper for tools, fishing spears, etc. After two successful attempts, he reached the Coppermine river in 1771, accompanied by Indian guides. This hazardous trip was indeed a remarkable feat when one considers the vast distance covered, a great deal of which was barren lands. At Bloody falls, (See Figure 1) on the Coppermine river, Hearne's Indians swooped down on a party of sleeping Esquimaux, who gathered there each summer to fish, and murdered the entire band encamped on that side of the river. Hence the name of the falls. Hearne's knowledge of minerals was undoubtedly limited. He reported having seen the copper mines from which the natives were securing the copper, but he failed to prove the economic possibilities of the copper occurrences or to give an accurate description of any deposit. Sir John Franklin visited the area in 1821. He and other members of his expedition, namely, Richardson, Back, Kendall, and Hood, reported native-copper float to occur in the vicinity of the Coppermine river and Bathurst inlet.

Jan 1, 1931

By R. J. T. Charles

Introduction An apparatus that will measure the surface area of a few of the simple minerals with a high degree of accuracy has been described by J. W. Bell (1). His apparatus consisted essentially of a photometric device that would measure the turbidity of fine particle suspensions. Turbidity, in this case, was considered as a function of surface area. Bell's method of surface area determination seemed to offer possibilities of extension and improvement to the point where it might approach a general method of particle size measurement. Theoretical and Practical Considerations of the Photometric Method In order to illustrate how turbidity may be considered as a function of average particle size, and to indicate the type of results expected from a photometric method of particle size measurement involving turbidity, the following theory may be hypothecated. If a number of particles, considered as spheres of uniform diameter, are placed at random in the path of a beam of light, the following expression, which will give the change in light intensity as a function of the diameter of the particles, the specific gravity of the material, and the weight involved, can be formulated from the Beer-Lambert Law:

Jan 1, 1951

By Boris Yacksic, R. W. Bruce

"The flotation of a cassiterite ore with oleic acid will recover primary or rougher concentrates assaying over 10 per cent Sn, with a recovery of 80 to 90 per cent. These rougher concentrates cannot be up-graded to a marketable grade by normal reflotation. Experiments were conducted on low-grade tin ores, and a process was developed for up-grading the rougher flotation concentrates by a reverse flotation technique. The process was tested on a number of samples of ore from the Catavi mine in Bolivia. The results of these tests showed that a concentrate assaying 40 to 60 per cent Sn could be readily produced, with a recovery of 60 to 75 per cent of the tin in the ore."

Jan 1, 1967

By Warwick D. Bullen

Gold mining in the Yellowknife area of the Northwest Territories started long before the concept of sustainability entered the academic literature and by the time the term enjoyed widespread public acceptance, the Yellowknife gold mining industry was in its sunset years. Nevertheless, the city of Yellowknife will long outlive the gold mines that it was founded on, demonstrating that not only can mining build sustainable communities, but that sustainable mining as a concept is an entirely valid precept. To this effect, the authors examine the complex economic and social aspects of the gold mining industry in the Yellowknife area over the last 70 years.

May 1, 2004

By H. S. Fowler

The Consolidated Mining and Smelting Company has been in the business of mining and exploration since its incorporation in 1906. The Company has reports written as early as 1890. Consequently, its files contain a very large number of reports, and also of maps, of ail descriptions. REPORTS Before describing the filing of maps, a brie{ note on our general system of filing reports will perhaps clarify the discussion. Reports of a non-periodic nature, primarily those based upon examinations by field engineers, are separated from all other data and filed in what we know as the Mine Series System. Each property on which reports are written is given a serial number, known as the Mine Series Number. This serial number is assigned at the time the first report is filed and it remains permanently identified with the property, regardless of its state of activity. Our mine series numbers now total over 5,000. The serial number for a property may be found by referring to an alphabetical index of properties. MAPS We found it necessary to divide maps into two groups: (1) Maps of properties (2) Maps of areas

Jan 1, 1944

By H. M. Kim, J. Rutqvist, D. W. Ryu

"Demand of high pressurized gas storage in underground rock caverns is increasing. Compressed natural gas (CNG) and compressed air energy storage (CAES) are one of the promising examples after since lined rock cavern (LRC) concept has been verified through in-situ pilot tests. Two key essential concerns of high pressured gas storage in underground rock caverns are mechanical stability of the cavern against high inner storage pressure and the risk of gas leakage from the caverns.In this study, we introduce our results of numerical simulations so as to investigate the potential of monitoring for gas leakage at a pilot facility for CAES in underground LRCs. The pilot facility was constructed at a comparatively shallow depth of 100 m, compared to the previous cases with several hundreds of meters, aiming at validating the feasibility of the LRC storage concept in which inner sealing liners, consisting of steel plate and concrete linings, are installed inside the excavated rock caverns (KIGAM, 2011). Compressed air may leak through either initial defects of inner containment liners such as imperfect welding regions and in-situ construction joints of the liners, or through structurally damaged points of the liners during the CAES operation where compression and decompression of the caverns are necessarily repeated and their structural robustness can be deteriorated.For this perspective, we carried out a coupled thermodynamic and geomechanical deformation analysis using TOUGH-FLAC simulator, and investigated the effectiveness of strain monitoring method in detecting mechanical failure of liners which may provide major pathways of air leakage. We therefore used an equivalent continuum model to relate the localized tangential strain to fracture permeability changes, which was developed in our early work (Rutqvist et al, 2012). In detecting and characterizing the leakage location, we tested a cross correlation technique using the synthetic pressure responses monitored in case of the failure of the inner liners. From the investigations, we showed that tangential strain, rather than radial, monitoring especially at the inner face of the sealing liners can be more effective in detecting the mechanical failure of the liners.In localizing the leakage point, we noted that the interface between the inner liners and surrounding rock may not be perfectly bonded so as to increase permeability through which any leaking air pressure may migrate more dominantly. We also demonstrated that the cross correlation of the time histories of pressure measurement especially at these interfaces can be useful in identifying the leakage point. These results may provide useful information in overall design of monitoring and alarming system of our upcoming CAES pilot facilities."

Jan 1, 2015

By T. Prietl

Metallurgical vessel linings are multilayered, consisting of refractory bodies, insulation materials, joints, and additional space to control for thermal expansion. A unique biaxial hot testing press (BHTP) was installed at the RHI Refractories Technology Center Leoben, Austria to enable the three-dimensional behaviour of complex vessel lining segments to be investigated under simulated service conditions. Using the BHTP, the heat up and thermo-mechanical behaviour of magnesia chromite brick lining segments with and without mortar filled joints were examined. The results obtained during the initial heat up provided validation of CFD modelling of the lining system. In addition, after the heat up and under steady state conditions, the lining behaviour during deformation-controlled compression and relaxation was examined. These analyses generated important data regarding the stiffness, joint compressibility, and brick damage of the lining segments after cyclic loading and unloading as well as the benefits of using mortar joints in the lining. These investigations were performed in collaboration with the Christian Doppler Laboratory for Secondary Metallurgy of Nonferrous Metals, University of Leoben, Austria. The BHTP has been operational since November 2004 and is providing information regarding the thermo-mechanical behaviour of different lining segments.

Jan 1, 2007

By H. Rozovsky

This paper deals with the large iron ore concentrating plant owned by the Iron Ore Company of Canada. The plant is part of the Carol Project, which is being developed in the Wabush area of western Labrador. The mining and milling operations were officially opened in July of this year. The handling of fine material has always been considered a serious operational problem. The crushing, grinding and sizing of 50,000 tons of iron ore per day, in a dry state, could present sizeable problems in maintenance and orderliness. The operation, as a whole, embraces many recent developments in the iron ore industry. Mining operations include the latest techniques of jet piercing and blasting. Primary crushing involves a single crusher, which handles the complete production. Grinding of the ore includes the latest concepts of dry autogenous grinding in air-swept mills. The actual concentration of the ore is per-formed, in the wet state, by the use of spiral concentrators, with provision for possible flotation or magnetic separation, if required. The upgraded concentrates are either stored or pelletized, prior to shipment by rail to Seven Islands.

Jan 1, 1962

By D. J. Wesolowski, D. A. Palmer, P. Bénézeth, S. Hilic

The equilibrium solubilities of gibbsite, Al(OH)3, and boehmite, A1OOH, have been extensively studied in our laboratory from 30 to 90°C, and 100 to 300°C, respectively, to ionic strengths of 5 mol.kg-1 (NaC1) over a wide range of pH. The resulting solubility constants have been treated with consistent empirical models that incorporate appropriate experimental data taken from the literature. These studies were initiated in part to understand and quantify scale formation in geothermal fields as a result of fluid re-injection from electric power generating plants. Most of the experimental results were obtained through application of a unique potentiometric method that allows for rapid, precise measurement of the in situ pH and allows the approach to equilibrium to be monitored from under- and super-saturation. The experimental program was extended to deal with more basic solutions (e.g., five molal NaOH), in which the dissolution of boehmite was measured for application to the refining of bauxite by the Bayer process. More recent results in strong caustic solutions at temperatures below 90°C were obtained to investigate the dissolution of aluminum-containing sludge from holding tanks at the Savannah River waste reprocessing site. In this case the solubility enhancing effects (kinetic and equilibrium) of triethanolamine were also established and quantified. Finally, potentiometric solubility experiments were conducted (50°C in 0.l mol-kg-1, NaCl) on aluminum alloy sheets to identify mainly the nature of the aluminum oxide/hydroxide surface layer formed under these conditions.

Jan 1, 2004

By Ltd. (CYMCO) Technology Center Yunnan Metallurgical Group Co., S. Jian, T. Song, J. D. Miller

"As sulfide zinc ore deposits become exhausted, nonsulfide zinc ore deposits become the other resource for zinc production. However, flotation for zinc recovery from nonsulfide deposits is much more difficult than the flotation of sphalerite from sulfide deposits and may become an option for zinc production only if a suitable processing technology is developed. In this regard, research efforts are being devoted to the flotation of nonsulfide zinc oxide minerals. Some common methods which have been used for the flotation of zinc oxide minerals include sulfidization-flotation, activation, and direct flotation with anionic and cationic collectors. The traditional flotation techniques have low efficiency and difficulty in separation and recovery of the zinc minerals from gangue minerals, for example, smithsonite (ZnCO3) from other carbonate gangue minerals and hemimorphite (Zn4Si2O7 (OH)2·H2O) from silicate gangue minerals. In this study potassium lauryl phosphate was evaluated as a collector for the flotation of nonsulfide zinc minerals. Results from contact angle and microflotation experiments at pH 6–9 show that hemimorphite (Zn4Si2O7 (OH)2·H2O) can be floated from quartz and that smithsonite (ZnCO3) can be floated from calcite. However, when dodecylamine, which is a common collector reported in literature for the flotation of nonsulfide zinc minerals, was used as collector, no significant difference between nonsulfide zinc minerals and gangue minerals was observed at any pH value. Initial evaluation suggests that potassium lauryl phosphate is effective at low concentration and may be a promising collector for zinc oxide mineral flotation.INTRODUCTIONBefore the twentieth century, zinc was mainly produced from nonsulfide ores (Large, 2001; Gilg, Boni, & Cook, 2008). With the development of differential flotation processes in the late 19th century major production switched from nonsulfide zinc sources to sulfide zinc ores (Hitzman, Reynolds, Sangster, Allen, & Carman, 2003; Gilg et al., 2008). However, as it is becoming more difficult to find new sulfide ores, recovery from nonsulfide deposits is being considered. Nonsulfide flotation for zinc recovery is much more difficult than the flotation recovery of sphalerite from sulfide deposits and may become an option for zinc production if a suitable technology is developed. Zinc and lead oxide ores are difficult to beneficiate ores due to their similar floatability with gangue, high solubility in water, and the influence of slimes (Fa, Miller, Tao, & Li, 2005). In order to improve the performance of oxidized minerals, lots of effort is being devoted to this field of study (Ejtemaei & Mahdi, 2014)."

Jan 1, 2016

By E. C. Goodhue, R. D. Coleman, I. E. Puddington, A. F. Sirianni

Iron ore samples containing apatite are fractionated to acceptable products by spherical agglomeration methods. The phosphorus is upgraded by a factor of 10 at an elevated pH. High-grade iron products are obtained in good yields from the tailings in a second step of the operation. The grade of the phosphorus separated appears to reach a maximum at about pH = 10; recovery of iron decreases below about pH = 4. Both the recovery and grade of iron are found to be reduced sharply above about pH = 8.

Jan 1, 1968

By Robert B. Parsons

"The last edition of Tax Notes expressed concern about two proposed tax changes in Finance Minister Paul Martin's 1995 budget that could have detrimental effects on Canada's mining industry. This month, Tax Notes expands on these concerns. This article is based on a paper that the author presented at ClM '95 in HalifaxIntroductionOn a global basis, there are more investment opportunities in the mining industry today than at any other time in history. Countries in Central and South America, Eastern Europe, the CIS, Central Asia, and Asia are competing aggressively to attract investment to all sectors of their domestic mining industries. Today, the demand for investment dollars exceeds the amount of dollars that are available for investment in mining. It is not surprising, then, that the established mineral producing nations are witnessing a decline in spending on exploration and development on their home turf, and an increase in spending in developing countries. In the context of a developed country such as Canada, there are two manifestations of the problem of declining investment: (I) Foreign investors are allocating more of their capital budgets to new opportunities in developing countries; and (2) Canadian juniors and seniors are spending proportionately more abroad. This shift in global spending patterns is the source of some concern for the future of Canada's mining industry, particularly because it is widely believed that the current rate of discovery of ore reserves in this country is too low to replenish depleting reserves.""Government bashing"" has always been a popular pastime in Canada. Invariably, this pastime has focussed, at !east in part, on taxation. In view of the intense competition that Canada faces on the global mining scene, it is important that the role of taxation in the decision-making process be kept in perspective. This paper seeks to put the role of taxation into perspective."

Jan 1, 1995

By Håkan Schunnesson, Kirsten Holme

"When mining high grade, narrow ore bodies, the mining method often implies a very detailed knowledge of the ore contacts to avoid unacceptable ore loss and waste rock dilution. During the past decade, the use of microprocessor based drill monitoring equipment has become an accepted technique, even for percussive drilling. On the basis of the recorded drill performance, such as penetration rate, torque pressure, thrust etc., a fast evaluation of the lithological sequence of the ore zone can be made. In order to evaluate the potential of percussive drill monitoring to pro-vide detailed information of the geometry of the ore body, the technique was tested in the Viscaria copper mine in Sweden during 1996.To provide understandable information to the mine geologist, great emphasis was placed on the separation between the drilling response generated by variations in rock conditions from variations caused by the operator and the drill system. Due to the complicated geology in Viscaria, the drilling response presented to the geologists was separated in two independent signals, one representing the hardness of the rock and one representing the in homogeneity(fracturing) of the rock. With those signals a good separation between different rock types in the ore horizon was achieved.The experience from the Viscaria copper mine is that drill monitoring not only can be used to locate contacts between rock types, but also to characterize rock conditions and, often, also to specify the exact rock type present. Because it is possible to get the drill monitoring information very quickly it is a valuable complement to diamond drilling for increasing the specific knowledge of the geology and the ore body."

Jan 1, 1997

By J. Kochhar, Robert G. Cooper

"The Cape Breton Development Corporation is a federal Crown corporation which was formed in 1968. Initially, the Corporation had two divisions - the Industrial Development Division, whose purpose was to stimulate Cape Breton Island's economy, and the Coal Division with a mandate to phase out the operating coal mines. However, that strategy changed in the early 1970s with the Middle East oil crisis. As a result of that crisis, Nova Scotia Power Corporation adopted an ""off oil"" policy. Today, approximately 700/0 of Nova Scotia power needs are met by generation of electricity from coal. Therefore, since the early 1970s, emphasis has been on the rehabilitation of the Cape Breton coal mining business with the opening of three new mines.Today, Devco is solely a coal mining company which employs 3300 people.Physical DescriptionThe mines operate in the Sydney coal field which is located on the eastern tip of Cape Breton. The Corporation leases the deposit from the province of Nova Scotia and its leases cover all coal from the outcrop to the 4000 ft depth. The seams outcrop along the shoreline and dip beneath the ocean floor at dips varying between 5% and 100%.There are eleven seams, of which three - the Harbour, Phalen, and Hub - have been extensively mined."

Jan 1, 1990

By M. D. Everell

Le Centre de Recherches minérales (CRM), qui est un organisme de recherche appliquée du ministère de l'Energie et des Ressources du Québec, a été créé en 1969, dans le but de procurer un support scientifique et technique à l'industrie dans le domaine des mines et de la métallurgie. Pour atteindre ses objectifs, le CRM met à la disposition de l'industrie un personnel spécialisé et compétent dont une quarantaine d'ingénieurs et de scientifiques. Etant donné la nature même de l'industrie minérale, ce personnel est très versé dans l'étude des problèmes diversifiés des domaines de la technologie minière, du traitement des minerais, de la métallurgie extractive et de l'analyse minérale. Ce Centre de recherches met également à la disposition de l'industrie une usine-pilote permettant de reproduire les résultats du laboratoire au moyen d'un appareillage de type industriel, d'obtenir des échantillons en quantité suffisante pour une exploration du marché et de familiariser du personnel avec les opérations normales de l'industrie. Certaines de ses contributions récentes au développement de l'industrie minérale du Québec seront présentées.

Jan 1, 1985

By Cris Sideco

This paper describes the concentration processes of the Sullivan. Concentrator, including crushing , transportation, sink-float, grinding , flotation and dewatering. Handling of hot muck has had a deleterious effect on most of the processes, resulting in significant operating problems and poorer metallurgy. These problems are described -in detail. THE SULLIVAN CONCENTRATOR is situated in Kimberley, high up in the Purcell Range of the Selkirk Mountains, at an elevation of 3,600 feet, approximately 4 miles from the Sullivan Mine (see Fig. 1). The original plant went on stream on August 23, 1923 at a designed capacity of 2,500 tons per day. This has been increased in stages to its present rated capacity of 11,000 tons per day. The latest stage was in 1949, when several major projects, including the underground crushing plant, the sink-float plant and the installation of a rod mill, were completed. Some 112,800,000 tons of ore have been treated in this concentrator to November 1975. The plant started on a 48-hour/ week schedule, but was reduced to 44 hours/week in October 1946 and down to 40 hours/week by the end of 1949. Except for a 6-month period in 1952 when the mill operated continuously, the 40-hour/week, Monday to Friday schedule was in effect.

Jan 1, 1977

By R. Lapcevic, P. Lokin

"Among other components, ore body „T“ was discovered in the Bor pit copper mine at a depth of app. 500m. The ore body is relatively small: 60-65m long, 40-45m wide and up to 50m high, but with an extremely high content of copper and accompanying metals. The rock mass containing the ore body is composed of altered andesite of relatively poor physical-mechanical characteristics. The exploitation of this ore body by way of conventional mining methods was associated with high risk, cost, and potential losses of the rich ore. Due to everything specified hereinbefore, the adopted solution involved ore exploitation with complete ensuring of excavation stability, thus forming an extremely large underground opening. The excavation and supporting were performed according to the NATM principles along with applying shotcrete, 9-25 m long cables, and horizontal and vertical lattice girders. The excavation of the ore body was completed in app. 2.5 years, all the while ensuring complete stability and security of people and equipment; construction works were constantly monitored. The proposed solution for ore excavation enabled more than 95% exploitation of ore as requested by the Investor, while depletion due to waste-rock excavation was less than the allowed 5%. INTRODUCTIONThe Bor copper deposit is located in Eastern Serbia. Copper exploitation in Bor commenced as far back as 1902. A total of 26 ore bodies varying in size and valuable mineral content have been excavated so far. One of the most recent excavated ore bodies is ore body „T“, which is one of the smallest bodies by volume, but also a body with one of the largest content of copper and accompanying metals. An important fact regarding its exploitation is that it is located at a depth of app. 500 m; that its shape is irregular: 60-65 m long; 40-45 m wide and app. 50 m high; and that it lays within a rock mass of relatively poor physical-mechanical characteristics. In addition, above it, in its immediate vicinity, ore body „F“ was previously excavated and its room was refilled with backfill and water. Excavation methods common in mining practice (excavation with caving, excavation with backfilling, excavation with protective pillars) were inadequate in this case for various reasons:• The immediate vicinity of the previous ore body „F“ room could cause expansion of the caving zone also to that room, along with penetration of groundwater and flotation sludge;• Possibility of deformation expansion caused by caving as far up as the surface of the terrain, including the urban area;• Difficulties in maintaining the stability of excavation sidewalls having steep slopes and great height;• Significant loss of ore mass with a relatively high content of metals etc."

Jan 1, 2015

By J. E. Nesset, W. Zhang, J. A. Finch

Frother influences water recovery through control of bubble size and a chemical effect. De-coupling the two is necessary to establish the extent of the chemistry effect. A setup is described to give steady state water overflow rate (Jwo) along with measurements of bubble size into and on top of the froth. Arguing neither bubble size correlates directly with water overflow, a frother mass balance is solved to estimate the bubble surface area flux in the overflow (Sb0 ). The solution required measurement of frother concentration using TOC analysis and frother adsorption density using surface tension data. The relationship between Jwo and Sbo reveals the frother chemistry effect, quantified for discussion purposes by an equivalent water layer thickness.

Jan 1, 2009

By P. K. Kaiser, S. M. Maloney, S. P. Singh

"Corrosion of underground support measures constitutes a concern to industry in both safety and economic terms. It also represents a potential market for corrosion resistant materials such as stainless steel.In order to assess the market potential for a stainless steel friction rock bolt, a review of current corrosion processes and remedial or preventative measures in the underground environment was undertaken. This was supplemented by distribution to industry of a detailed questionnaire, concerning the magnitude and extent of support corrosion and the costs of current support measures, and by visits to selected sites. Following data synthesis, support costs were established and the economic benefit of stainless steel rock bolts evaluated.Stainless steel rock bolts can be an effective cost reducing measure in unscreened areas requiring frequent reconditioning. Their benefit is rapidly diminished, however, if only partial reconditioning is required, the reconditioning interval is long or if screening is required.While most industry personnel are receptive to the application of stainless steel support measures, the localization of corrosion problems and the potential high cost of this type of support are barriers to its widespread implementation. They have potential for use in extreme environments. However, this relatively small market may not be economically viable.IntroductionFriction rock bolts are the simplest of all interior rock fixtures. The friction resistance to sliding of the rock on the bolt is generated by a radial pressure against the borehole wall over the length of the bolt. Two types of friction rock bolts are currently marketed, the Split Set and the Swellex.Unlike conventional point anchor bolts, friction rock stabilizers may move relative to the rock strata and maintain their capacity even if rock shifts, a condition that sometimes loosens or breaks conventional bolts. Ease of installation, effectiveness in jointed as well as weaker rock, and the possibility of having relatively long bolts are a few of the many advantages which generate considerable interest in the application of friction rock bolts (Wijk and Skogberg, 1982). However, due to their thin-walled construction and large surface area, frictional rock stabilizers are more susceptible than conventional bolts to damage by corrosion. For this reason, they are normally not recommended for long-term use (Jolly and Neumeier, 1987).In light of the above discussion; the Nickel Development Institute commissioned a study by the Geomechanics Research Centre with the objective of generating a credible database for the assessment of the feasibility of a stainless steel friction bolt system in corrosive ground and mine environments."

Jan 1, 1990

By R. W. Davis

INTRODUCTION CHURCHILL river was named for John Churchill, first Duke of Marl-borough and third Governor of the Hudson's Bay Company, in the latter part of the 17th century, some fifty years after the ill-fated Danish expedition, led by Munck, had abandoned the site of the now famous seaport of Churchill, as a worthless, cold, disease-ridden country. No other attempts were made to explore the interior until the river basin became a part of the grant to the Hudson's Bay Company and began to play its part in furnishing the luxury of fine furs to civilized people as it had furnished the necessities of food and dress for untold centuries to uncivilized natives. This was the sole contribution of the region to the economic life of the country for some two hundred and fifty years, until 1926, when the power site at Island Falls was discovered by engineers seeking a cheap power source to make possible the development of the great ore-body at Flin Flon. DRAINAGE BASIN OF CHURCHILL RIVER The river is some 1,325 miles long. Rising in the headwaters of the Beaver river, in east-central Alberta, it flows in an easterly direction across Saskatchewan and northeasterly across Manitoba to Hudson bay, through a remarkable basin of some 115,500 square miles, only 6,000 square miles less than the area of the British Isles. A journey down this river leads one through three distinct belts of country, each vastly different from the others geologically and in surface characteristics. For the first five hundred miles the river flows through a basin of 36,000 square miles of the great central-plains country, which is covered with fertile soil and carpeted in its southern part with prairie grass, which gradually gives way to the mixed forests of poplar, spruce, birch, and jackpine in the northern and eastern sections: About midway across Saskatchewan, bald-headed knolls and ridges begin to make their appearance as the river meets the western margin of the Canadian Shield. Then, for some seven hundred miles, it passes through country underlain by the pre-Cambrian rocks of the Shield, which continue to within one hundred miles of Hudson bay. Here the character of the country again changes to a low, clay plain underlain by sandstone, and through this 'clay belt' the river flows between steep clay banks, to empty into Hudson bay.

Jan 1, 1935