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By M. Pawlik, E. Arinaitwe, V. Ferrera

A series of flocculation tests were performed on dilute quartz suspensions with the use of five polyacrylamide-based flocculants of similar molecular weights but of different degrees of anionicity. The tests were performed as a function of ionic strength and pH. The macromolecular conformation of flocculants in solution was assessed through intrinsic viscosity measurements under the same physicochemical conditions as those of the flocculation tests. It was generally found that the flocculating efficiency of the polyacrylamides correlated with their ability to coil or stretch in solution. Polyacrylamides with the degrees of anionicity on the order of 10-18% showed the highest flocculating efficiency in terms of the settling rates of the flocculated solids and the residual turbidity of the resulting supernatant. At the same time, these most effective flocculants were also found to exhibit the greatest tendency to coil and stretch in solution. This result suggests that the flocculating power of a flocculant is determined not only by its ability to adsorb onto (and bridge) fine particles but also on its ability to conform to the size of the resulting floes.

Jan 1, 2009

By Roger T. Laine

"The Carswell structure, located in the western part of the Athabasca Basin, northern Saskatchewan, has been extensively explored since 1967. This exploration has been successful and lead to the discovery, in 1970, of the D sandstone-hosted unconformity related deposit. By the end of 1984, five additional basement-hosted unconformity related deposits had been delineated: the OP and N discovered in 1970, the Claude in 1971, the Dominique-Peter in 1981, and the Dominique-Janine in 1984. The D deposit has been mined out; the Claude open-pit has already produced more than 500 tonnes of uranium, the development of the Dominique-Peter underground mine (first phase) has been completed, and production from the latter started in 1985.All six deposits are located in the southern part of the Aphebian metamorphic core, 18 km in diameter, which has intruded at least 1250 metres of Helikian Athabasca Group sediments during a cryptoexplosion event at 480 Ma, unrelated to the emplacement of uranium mineralization. The metamorphic rocks, affected by the Hudsonian Orogeny, are divided in two lithostratrigraphic units: the Peter River gneiss, aluminous gneiss series, and the Earl River complex, mixed quartzofeldspathic and mafic gneiss series. A well developed regolith profile is recognizable in the south along the contact with the sandstone and inside the metamorphic core sometimes associated with conformable sandstone beds.Basement and sandstone-hosted uranium deposits show many similarities:-linkage to unconformity;-mineralogy and geochronology with a first phase mineralization characterized by a polymetallic sulphide-uraninite-brannerite assemblage dated at 1150 to 1050 Ma, a second phase characterized by a simple sulphide-uraninite assemblage dated at 890 to 820 Ma, and a third phase characterized by a pitchblende-hematite dated at 380 Ma; and,-linkage to early Hudsonian structures with remobilization of these structures during intense hydrothermal alteration resulting in Mg chlorite-illite halos."

Jan 1, 1986

By M. E. Wilson, A. C. Lee

"The property owned by Senator-Rouyn Mines, Limited, is in Rouyn township about 17'2 miles southwest of the town of Rouyn. It adjoins the Chadbourne claims of Noranda Mines, Limited, on the south and the Bagamac property on the ·west. It includes seven claims-block 44, blocks 80 to 83 and blocks 96 and 97; the mine is wholly in blocks 44 and 82.Late in 1936 gold was discovered in an outcrop of rusty weathering carbonate rock near the north end of block 44, and the following year the present Company was organized to proceed with the development of the property. During 1937-38, 17,000 feet of diamond drill core were bored to determine the extent of the ore deposit at depth. From October 15th, 1940, to April 15th, 1941, the ore was hauled to the mill at the Arntfield mine for treatment. The mill on the Senator-Rouyn property started on April 25th, 1941, and has been in practically continuous operation since than time. To the end of 1946, 574,874 tons of ore, from which gold having a value of $3,836,450 was recovered, were treated in the mill.GEOLOGYThe rocks exposed at the Senator-Rouyn mine, except in the southern part of the property, are almost wholly quartz diorite, part of an irregular mass that extends west from the town of Rouyn along the north shore of Noranda lake and thence southwest across the Senator-Rouyn claims. In the northern part of the propertyt inclusions of rhyolite occur here and there in the diorite. In the southern part the predominant rock is dacite and in the east-central part of block 44 claim andesite. Dykes of andesite, quartz syenite, and later diabase also occur on the property.The andesite of the Abitibi volcanics is not exposed on the property, but has been intersected in three diamond drill holes, one on the eastern boundary of block 44 and two farther west within the block. This andesite is probably the western end of a band of pillowed andesite well exposed in the Larose claim to the east."

Jan 1, 1954

By G. Bimpilas, G. N. Anastassakis

"Today, one of the most intense problems in mineral processing systems is referred to the treatment of fine (–100 µm), and even smaller size, particles. Fine mineral particles possess specific properties (small mass, high specific surface area, and high surface energy per unit area) that render their separation inefficient with conventional methods (physical, physicochemical) and equipment. As a result, it is not feasible to obtain a concentrate both of high grade and recovery in mineral value and a considerable amount of mineral fine particles is lost to the tailings. As evidence, we could cite numerous examples from industrial practice with considerable loss of mineral values to the tailings because of the fine particles size, e.g. phosphate, tungsten, tin, etc.The objective of the current paper is to investigate the possibility to separate magnetic gangue minerals and rocks (serpentine, ilmenite, and olivine) from magnesite by co-agglomerating all the gangue components and subsequent magnetic separation of the agglomerates.To meet the target, hydrophobic agglomeration tests were initially carried out on single minerals to define the favorable conditions for selective hydrophobic co-agglomeration of the gangue minerals. In this respect, the effect of the following factors was examined: pH, collector dose, conditioning time, and settling time of the agglomerates. Among the combinations examined, the most favorable proved that with amine in the basic pH region. The use of non-polar oil proved beneficial. The preliminary results were confirmed by tests on mineral mixtures. The application of magnetic separation resulted in the removal of gangue minerals and the recovery of magnesite concentrates of commercial grade (magnesite content 95% approximately) and high yield.The current paper contributes to the development of mineral processing, since it successfully copes with a very important problem of mineral processing, such as the efficient separation of fine particles."

Jan 1, 2016

By V. Schenk

Dust exposure resulting from the exploitation and winning of natural resources below ground has presented a serious health problem since the beginning of mining. The boom phase of the German hard coal mining industry after World War II with at times up to 500,000 employees saw an increase of dust exposure of miners below ground as the mechanization of road heading and mining increased significantly. More and more miners were diagnosed with coal-workers-pneumoconiosis (CWP), a chronic and irreversible lung disease resulting in a significant impairment of pulmonary function. This realization led to a reduction of CWP in the German hard coal mining industry in the 1960s. The successful fight against CWP began with the introduction of technical dust prevention measures. By infusing the coal seam with water before mining, sprinkling and spraying of heading and mining machines as well as canopies with water, aspiration in places with high amounts of dust and the suppression of dust with chemical substances it is possible to significantly reduce the miners? dust exposure. All operating points below ground are checked and measured regularly with regard to dust exposure. Through the combination of these values together with the individual shift data a relatively precise profile of individual dust exposure can be obtained. This profile allows the targeted work assignment when certain predetermined limits have been reached, moving the miner to a work place with less dust exposure and thus reducing the chronic dust exposure. The state of health of the individual is known because since about 60 years ago extensive occupational health checks have been carried out regularly at least every two years which means that work restrictions can be imposed depending on the findings. Since the beginning of the 1980s more value has been attached to not only situational but also behavioral prevention. Given the comprehensive provision of protective masks, having a protective effect as well as the required comfort when being worn, each miner has the opportunity to protect his respiratory organs depending on the specific dust exposure. Through a combination of all these measures the German hard coal mining industry has succeeded in beating the classic coal miner?s disease CWP. For mines in the Ruhr valley this means that a miner who started work after 1978 will no longer develop CWP.

Aug 1, 2013

By Stanley Davidson

"The ore deposit mined by Falconbridge Nickel Mines, Limited, is one of the numerous nickel-copper sulphide bodies marginal to the large oystershaped mass of differentiated norite in the Sudbury district, famous as the world's most important nickel producing field. The unique character of the ore deposits of the district has resulted in its intensive geological study over a period of more than 50 years. The results of these studies have given rise to a voluminous geological literature and to a great deal of controversy as to the genesis of the ores. This description of the structural geology at the Falconbridge mine is presented in the hope that it may form a small part of the chain of evidence leading to a reasonably satisfactory explanation of the ore genesis.The mine, named after Falconbridge township in which the deposit occurs, lies along the southeast margin of the norite mass, which, however, is h::re concealed beneath a deep mantle of glacial sands and gravels averaging over 100 feet in thickness. As a consequence, the deposit was not discovered by the early prospectors, and it was not until 1916-17 that E. J. Longyear, of Minneapolis, located the ore by drilling(ll). The discovery was foreshadowed in 1899 by the work of Thomas A. Edison, who found indications of the deposit by what is believed to have been a combination of magnetic and electrical geophysical surveys. He sank a prospect shaft over what has to date proved to be the largest and richest ore section in the mine. A wet quicksand layer at the rock surface proved impenetrable, however, and the 'Edison' shaft never reached bed-rock.The Falconbridge property was acquired by the Lindsley interests in 1928, and ore output, since its inception in 1929, has gradually risen from a modest beginning to the present 2,000 tons and more daily. Total production in this period is 7,500,000 tons of ore averaging 1.72 per cent nickel and 0.89 per cent copper, together with a small but valuable content of precious metals, principally of the platinum group."

Jan 1, 1954

By Max W. Ball

YOU have been kind enough to ask me to speak to you on "The War and Anglo-American Relations." A speaker always takes the liberty of putting his own interpretation on the scope of his subject. I am going to exercise that privilege, and try to look back over a generation of Anglo-American relationships and forward beyond the present war. I should like particularly to consider responsibilities as well as relationships. A more accurate caption for what I am going to say would be "Anglo-American Responsibilities.?? THE WAR WILL BE WON I am assuming that sooner or later we shall win this war. History and economics point to the same conclusion, that Germany has attempted the impossible and that the seeds of defeat are already sown. As to one ecof1:omic factor, I am already on public record as believing that Germany's oil supply is inadequate for the war she has launched. That opinion is unchanged. Aside from such tangible factors, moreover, I am convinced that the spirit of freedom is unquenchable, and that no combination of powers will be able to rout it from the British Commonwealth of Nations and the United States. Stronger even than this conviction is my faith in a God who will not suffer the defeat of man's aspiration to be master of his own soul. I am sure that all of you share that faith, and that we need not argue it. We can start with the assumption that the war will end in victory. The subject we are to consider, then, is the relationship of the English-thinking peoples during the conflict, and their joint responsibilities in the difficult days that will follow it. A CANADIAN-AMERICAN No talk on such a subject is worth listening to unless the audience knows the background and fundamental beliefs of the speaker. No human statement stands alone; behind and beside and within it are the ideals and the bias of the man who makes it. Because I am a stranger to most of you, I am constrained to talk about myself before I talk about more important matters. The review may be profitable, not because of the subject, but because it may illustrate the evolution of an attitude toward England.

Jan 1, 1941

The teaching of geophysics in Canada at the present time presents a variety of approaches to the subject, and the different paths adopted imply, in turn, an uncertainty in the minds of some educators as to the role this science is to play in the future progress of geology, and a hesitancy to commit themselves to foster its development. The pedagogical attitudes vary from a whole-hearted acknowledgment that the science of geophysics is fundamental to the understanding of terrestrial phenomena (including, of course, geological processes) to a hesitant immersion of the toe to test the water's temperature (which is, of course, essentially a geophysical experiment) before deciding whether or not the time is ripe for total immersion. The present discussion has been organized in the hope that it will help to clarify the roads to geophysics and assist educators in making a more understanding choice of the best paths for them to follow, according to their particular requirements and objectives. Before proceeding further, however, it is necessary to define the term geophysics and circumscribe the field it covers. In the first place, it should be emphasized that geophysics is NOT confined to the art of geophysical prospecting. The popularization of geophysics has unfortunately engendered a general misconception of the word, and consequently a tendency to ignore the wider meaning of the term. Etymologically, geophysics means the physics of the earth. It is so understood by the International Union of Geodesy and Geophysics and the various geophysical societies which adhere thereto. To them, geophysical prospecting is but a very small field indeed, which they consider had best be left to engineering and prospecting organizations.

Jan 1, 1951

By L. A. Homeniuk, R. Bonnar

"The Fond-du-Lac uranium deposit is located on the northern rim of the Athabasca Basin. The uranium mineralization is, for the most part, confined to the Athabasca Group, which is underlain by pre-Helikian metamorphic rocks of the Western Craton.The deposit is characterized by a remarkable train of mineralized glacial erratics which led to the original discovery. The mineralization is present as a ""high-grade"" core and a diffuse ""low-grade"" aureole. The ""high-grade"" core occurs as a stockwork of steeply dipping pitchblende veins which strike N 50°E. Hematite, siderite and secondary silicate are also abundant. The ""low-grade"" aureole contains uraniferous goethite, argillaceous material and rare carbon buttons. Recent alteration to coffinite has taken place along the margins of pre-existing ore minerals.The ""high-grade"" core is 390 m long and 10 to 40 m wide, and is surrounded by an irregularly shaped zone of ""low-grade"" mineralization with a similar length and a width of up to 350 m.Comparing the Fond-du-Lac deposit to other unconformity-type deposits, several important differences can be noted:1. Ninety per cent of the ore is above the unconformity, in the Athabasca sandstone.2. The deposit is not associated with underlying graphitic rocks or a major structure.3. The clay-rich alteration zone is not extensive around the Fond-du-Lac deposit.Although there are differences with other Athabasca unconformity-type deposits, the high-grade portion below the unconformity suggests a common origin.The ore deposit is postulated to have been formed from uranium-bearing solutions which entered the stockwork of fractures. Following the reduction in part of these solutions by pre-existing carbonaceous matter and pyrite and/or chemical reaction with pre-existing hematite, deposition continued as a result of decreasing temperature and pressure. Subsequently, minor supergene redistribution of the uranium has taken place."

Jan 1, 1982

By L. A. Homeniuk, R. Bonnar

"The Fond-du-Lac uranium deposit is located on the northern rim of the Athabasca Basin. The uranium mineralization is, for the most part, confined to the Athabasca Group, which is underlain by pre-Helikian metamorphic rocks of the Western Craton.The deposit is characterized by a remarkable train of mineralized glacial erratics which led to the original discovery. The mineralization is present as a ""high-grade"" core and a diffuse ""low-grade"" aureole. The ""high-grade"" core occurs as a stockwork of steeply dipping pitchblende veins which strike N 50°E. Hematite, siderite and secondary silicate are also abundant. The ""low-grade"" aureole contains uraniferous goethite, argillaceous material and rare carbon buttons. Recent alteration to coffinite has taken place along the margins of pre-existing ore minerals.The ""high-grade"" core is 390 m long and 10 to 40 m wide, and is surrounded by an irregularly shaped zone of ""low-grade"" mineralization with a similar length and a width of up to 350 m.Comparing the Fond-du-Lac deposit to other unconformity-type deposits, several important differences can be noted:1. Ninety per cent of the ore is above the unconformity, in the Athabasca sandstone.2. The deposit is not associated with underlying graphitic rocks or a major structure.3. The clay-rich alteration zone is not extensive around the Fond-du-Lac deposit.Although there are differences with other Athabasca unconformity-type deposits, the high-grade portion below the unconformity suggests a common origin.The ore deposit is postulated to have been formed from uranium-bearing solutions which entered the stockwork of fractures. Following the reduction in part of these solutions by pre-existing carbonaceous matter and pyrite and/or chemical reaction with pre-existing hematite, deposition continued as a result of decreasing temperature and pressure. Subsequently, minor supergene redistribution of the uranium has taken place."

Jan 1, 1982

By J. W. Smith, J. Van Dusen, A. Papachristodoulou

"As part of a study to evaluate factors affecting tankroom air quality, the mechanism of aerosol generation from bursting bubbles in electrowinning operations has been investigated. Typically 2 to 3 mg/m2.s are produced in zinc tankrooms. Analysis shows that the rate of production of film drops (geometric mean diameter - 2 urn] increases with decreasing bubble size, and that jet droplets (geometric mean diameter - 20 um) are not produced with gas bubble larger than - 4 mm. Both mechanisms of drop formation and current efficiency are affected by surface active agents, with an over-all reduction in emission of up to 60% to 70% being achievable. A source control system which does not adversely affect electrolyte properties is always preferred, and coalescence of all gas bubbles in to a continuous stream of gas at a single point on the electrolyte surface would eliminate aerosol emissions. This objective was the basis for design of a coalescence device which, in laboratory tests, reduced the emission rate by over 95%.The control device fit s over the electrodes in the electrowinning cell and is partially immersed in the electrolyte. A number of changes in the design which resulted in significant improvement in the performance of the device are reported.Field tests have shown that only about 75% of the aerosol below 10 um can be eliminated by coalescence. The remainder (up to 95% of the total) is controlled by coalescence of droplets, by impaction on the exposed collector surface and gravitational settling.The device does not interfere with operation of the tankroom, handles the effect of surges in power during harvesting, and is simple and inexpensive to maintain. IntroductionDuring the electrowinning of metals (such as zinc and copper) gases are evolved along the electrode surface forming small bubbles. The bubbles travel upwards and burst on the electrolyte free surface generating, in this way, small droplets. Because the electrolyte is often highly acidic or contains toxic materials, the whole process can result in the formation of an aerosol in the atmosphere above the electrowinning cells which poses a serious health hazard to workers in the area, and corrodes equipment."

Jan 1, 1988

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 E. Asselin, P. Sauve, H. Salomon-de-Friedberg

"Residues from the CESL Copper process were leached using the CESL Gold process. The kinetics of reaction were confirmed to be fast with over 50% of the gold consistently extracted within 2 minutes of leaching. Final gold extractions under the conditions tested here were between 80-90% obtained within 90 minutes. A model for the CESL Gold process was developed. This model is slightly different based on whether the copper concentrate leach residue was ground or unground prior to leaching: the gold leaching rate constant is approximately twice as fast for the ground samples. Unground residues had a P80 of 13 ?m whereas ground residues had a P80 of 10 ?m. The model predicts a 43% decrease in leaching time for ground residue versus unground residue to achieve the same extraction under otherwise identical conditions. The model was more accurate for the ground samples. INTRODUCTIONTeck's CESL Process (Jones, 1996) was developed to provide an economically attractive alternative to traditional copper smelting. It has since evolved to also deal with copper concentrates containing valuable impurities such as nickel and undesirable ones, such as arsenic, while reducing downstream costs. Effective recovery of gold and silver is essential to the economics of the CESL Process. The Brook Hunt 2007 copper concentrate assay data (Wood-Mackenzie, 2007) were examined to determine the ratio of gold plus silver value relative to the contained copper. As indicated in Figure 1 below, nearly two-thirds of concentrates have 10% or more of their total value tied up in their precious metals content.CESL has extensively examined the recovery of gold and silver at bench, pilot and demonstration scale, which has culminated in the present CESL Gold Process (Barr et al., 2007). The process targets the precious metal contained in the leach residues produced in the copper portion of the flowsheet. This residue has two primary components which influence downstream processing. The major iron-rich fraction (-75 wt%) of the residue is a mixture of various forms of iron oxide precipitates including hematite and jarosite (Sahu and Asselin, 2011). The iron fraction ranges from amorphous to crystalline in nature depending on the compound precipitated, upstream operating conditions and feed material composition. The lesser, but by no means less important, fraction is a mixture of elemental sulphur and unreacted sulphides (principally pyrite).Elemental sulphur formed during the oxidative leach of the copper concentrate reacts with cyanide to form thiocyanate (SCN-) making a traditional cyanide leach approach too costly. Since the SCN formation reaction strongly depends on contact time with the CESL residues (Po, 2007) short contact times were preferred. This factor guided the development work towards the eventual room temperature, pressure cyanidation process which results in near complete gold dissolution in 90 minutes. A recent CESL gold demonstration campaign treating 1.5 t/d of residue from the copper oxidation step achieved an average gold extraction of 91% (96% maximum)."

Jan 1, 2012

By S. Yannacopoulos, L. Bichler, P. Wanjara, J. Gholipour

Characterization of a virgin and in-service Inconel 718 alloy was undertaken to study the changes caused by the service conditions on the grain size, ?? phase, MN-type nitrides and MC-type carbides. The size, distribution and volume fraction of these phases and grain size were studied using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscattered diffraction (EBSD) analyses. A considerable difference in the grain size, as well as distribution and volume fraction of the precipitates was observed in the in-service material as compared to the virgin Inconel 718. As a result of these microstructural changes, a notable dissimilarity in hardness between the materials investigated was observed. The results presented in this study are important for proper development of repair parameters and heat treatment of in-service Inconel 718 material.

Jan 1, 2014

By R. C. E. Bray, Peter Price

"The property of Pamour Porcupine Mines, Limited, is in the eastern Porcupine area, about 12 miles northeast of Timmins. It covers parts of lots 3-6 (inclusive), cons. 5 and 6, Whitney tp., Cochrane district, Ontario. It is an amalgamation of the old La Palme, Three Nations, and Porcupine Grande properties.The first discovery on the Pamour was made in 1911. During 1911 to 1914 a small shaft was sunk on the Three Nations vein to the 200-foot level and a 100-ton stamp mill was put in operation, but only a small production was achieved. The property remained idle from 1914 to 1923. In 1924 some diamond drilling was done along the Keewatin-Timiskaming contact with some encouraging results, but the gold mineralization encountered was too low in general at the price of gold then prevailing to warrant further · work. The increase in the price of gold revived interest in the area, and the above noted amalgamation was effected in 1934. Options were taken and successively dropped by two large mining companies. Following this, exploration both on the surface and underground was started by Quebec Gold Mining Corporation, Limited. Diamond drilling in the early part of 1933 showed considerable ore in conglomerate and greywacke to the east. In the middle of 1935 Noranda Mines, Limited, assumed control and management. A new shaft was sunk and the property was ·equipped with a mill having an initial capacity of750 tons a day. This was subsequently enlarged to 1,500 tons a day.From the commencement of milling (May 16, 1936) to the end of 1946, 5,025,545 tons of ore having an average grade of 0.1327 oz. a ton ($4.64 at $35 an oz.) have been mined and milled."

Jan 1, 1954

By J. A. Chamberlain

DURING a recent trip across Canada and parts of the northern United States, the. writer examined some forty mine models. Construction -details and the uses to which the models were being put were outlined in a report to Eldorado Mining and Refining, Limited, and a specific model was proposed on the basis of the Company's particular needs at their Beaverlodge operation. It was felt, however, that portions of the report would be of some value to anyone contemplating building a mine model. For this reason, a synopsis of some of the more important aspects of the problem is presented here, together with a suggested model type that appears to have wide application. Thanks are due not only to Eldorado for permission to publish the following material, but also to the many mine personnel across Canada who allowed the writer to examine their models and gave freely of their time in discussion.

Jan 1, 1958

By E. I. Robinsky

"In light of the recurring spills and failures of conventional tailings disposal pond dams, a brief review of the Thickened Tailings Disposal (TTD) system is presented. It is shown that by the process of thickening the tailings to a heavy slurry prior to disposal, it is possible to create a self-supporting deposit of tailings and to eliminate the typical superimposed settling pond. These features, together with the ability to reclaim the disposal area even as mining continues, preclude an ecological disaster. IntroductionMine tailings spills are really not such rare occurrences. They have been happening on many continents, in many countries. Neither Canada nor the United States have been spared. In Ontario, the most recent spill occurred at a closed-down tailings disposal area in Matachewan, in 1991.Such continuing disasters could be avoided if a different approach were taken to the disposal of tailings wastes. The recent failures at the Los Frailes mine in Spain, the Omai mine in Guyana, and the Marcopper mine in the Philippines, will hopefully shake up the industry to consider other methods of disposal. The reason why the failure of a conventional tailings disposal dam is so environmentally disastrous is not the dam itself, but the fact that the dam retains a mass of very loose unconsolidated tailings and a great deal of water, or process fluid1. If the dam fails, the contents liquefy completely as they flow through the breach. In this liquid state, they can flow many miles downstream. If the dam itself were built of tailings material, as is often the case, it too would liquefy and join the flow.The reason the material is so loose in the first place is that it has been discharged into a pond filled with water. The tailings particles drift down through the water, their weight reduced by 50% due to buoyancy, to form a loose structure, like a “house of cards,” or lakebottom mud. It doesn’t take much of a shock to collapse the material into a liquefied state."

Jan 1, 1999

By P. M. Huck, R. John

"The National Uranium Tailings Program was established in 1982 to develop, in part, a mathematical predictive model which would allow the assessment of the impact of uranium mill tailings on the environment and particularly on humans. . To achieve this , various studies were undertaken to establish the role played by key constituents of the tailings. This paper summarizes the findings of a study carried out under that program, to examine the leachability of barium-radium sulphate sludges produced in the treatment of uranium mill tailings decants. The investigators performed detailed chemical an alysis of the sludge, applied geochemical computer models to investigate sludge leaching behaviour, and conducted experiments to assess the impact of bacteria on leaching. The modelling showed that the redox state o f the sludge-leachant system was the most important factor. Substantial bacterially-mediated dissolutio n of the sludge and release of radium was demonstrated experimentally under suitable reducing conditions . INTRODUCTIONIn September 1981, Phillip A. Lapp presented the final report of the National Technical Planning Group on uranium tailings research to the federal government (Lapp, 1981). Lapp' s group had performed an in-depth survey of the status of uranium tailings research in Canada and, as a result, recommended that a national program be funded in the amount of $18 .6 million. Half of this fund ing was to come from the federal government, with the two producing provinces , Ontario and Saskatchewan, providing the balance. However , the provinces declined to support the program and the federal government decided to inaugurate a reduced program with $8.5 million o f funds .In late 1982, the formation of the National Uranium Tailings Program (NUTP) was announced by the minister of state for mines. A primary objective of this program was to develop a mathematical predictive model that would permit the assessment of the impact of uranium mill tailings on the environment, a nd particularly on humans. The program was to use existing information to the greatest possible extent, and then fund research to fill in gaps or substantiate data where necessary .The NUTP was established to administer this program of contract research over a five-year sunset life. By the end of the 1986-87 fiscal year the NUTP had completed about 100 contracts. One of those projects was to study the effect of placing barium-radium sludge ba ck within the tailings matrix. Th is paper gives the results of that study."

Jan 1, 1989

By G. M. Brownell

Introduction The Flin Flon mine is located on the boundary line between the provinces of Manitoba and Saskatchewan at a point about four hundred miles northwest of Winnipeg. A branch of the Canadian National railway provides the town of Flin Flon with direct transportation facilities. The property was staked in 1914 and, after a considerable amount of exploration; the Hudson Bay Mining & Smelting Company was organized and brought the property into production in November, 1930 (1). Mining is carried on by open pit and underground methods at the rate of about 4,400 tons per day. Production for the year 1934 was: 99,334 ounces of gold; 1,335,319 ounces of silver; 37,486,054~pounds of copper; and 49,427,280 pounds of zinc; in addition to small amounts of cadmium and selenium. The Flin Flon deposit is one of the largest low-grade ore deposits in Canada with complete hydro-electric and metallurgical plants for the production of blister copper and electrolytic zinc. Previous Work The development of the Flin Flon mine into one of the major mining operations in Canada has created a need for a more detailed geological study of the area. Practically all of the information published to date concerns the general surface features. It is the purpose of this paper to deal more specifically with the ore-body and its relationship to the enclosing rock as revealed by studies made possible through recent underground development. The earliest published report on the area is by E. L. Bruce (2), who made a reconnaissance geological investigation of the region for the Geo-logical Survey of Canada in 1914 and established the main. petrological units. Several years later the area immediately around Flm Flon was mapped in greater detail by F. J. Alcock (3). In the summer of 1934, the area of Missi sediments to the north and east of the mine was studied by J. W. Ambrose. His report has not yet appeared in print but his findings are of importance.

Jan 1, 1935

By W M. Cameron

Geophysical studies have extended seaward in recent years, and the important discoveries which have been made have led to a better understanding of geological processes. A present source of certain minerals, the sea will eventually serve as an important source of desalinated water. The continental helves, in particular, represent a potential mineral resource. The expansion of Canadian oceanographic effort that is now underway will eventually lead to the exploitation of the wealth beneath the sea. THE subject of this symposium, which emphasizes the word "geophysics," the specialties of the speakers who are contributing and the nature of the audience at first made me believe that I, a a physical oceanographer, would be out of place. However, I shall undertake to classify myself as a geophysicist, and shall arrange my remarks on my specialty o that they might be of interest to those of you who are predominantly geologists, metallurgists or mining engineers.

Jan 1, 1963