Search Documents

By C. Dupuis, P. Waite, S. Leboeuf

Casthouses throughout the aluminium industry commonly use chlorine gas as a fluxing agent for furnace and in-line treatment of molten aluminium alloys. Its positive impact on the removal of alkali elements and non-metallic inclusions is well known. Nevertheless, the elimination of its use is highly desirable due to the safety and environmental risks associated with storage and handling. Over the past decade, the aluminium industry has significantly reduced its chlorine consumption. This has been achieved by maximizing the chlorine gas utilization efficiency during metal processing, and by the chlorine replacement for crucible and furnace metal treatment applications. Operation of sealed in-line treatment units without chlorine is now possible, but with lower or inconsistent removal efficiency penalties for alkali and inclusions respectively. This paper reviews the progress made at Arvida Research and Development Centre regarding the reduction of chlorine and the development of an alternative to chlorine for in-line metal treatment without penalizing the metallurgical performance.

Jan 1, 2006

By J. A. Folinsbee, Andre Robitaille, Tony Y. Chong

"Conventional crushing and grinding is followed by gravity concentration to recover free milling gold. Refractory gold, finely disseminated within the pyrite and arsenopyrite matrix, is recovered by flotation followed by pressure oxidation, cyanidation, and cementation. Non-refractory gold is recovered by cyanidation/CIP processing.A comprehensive test program aimed at improving flotation recovery was initiated in June 1995. Plant testing indicated that flotation tails value could be significantly reduced using mechanical flotation cells. Based on these test results, a flotation circuit that incorporates one of the three existing flotation columns followed by mechanical scavenging and cleaning was developed. Detailed engineering was completed in September 1996. Construction started in February 1997 and was completed in 3 months at a cost of $3.2 million. An on-stream X-ray analyzer was installed to provide real-time arsenic and iron analyses and inferred sulphur value on some of the flotation streams.The new flotation circuit proved to be an instant success. Flotation tails values were reduced by 27%. Final tails solids and solution was reduced from 0.035 to 0 023, and 0.0014 to 0.0006 oz/ton Au, respectively. Based on a mill throughput of 1,620 stpd this decrease in tails value will result in an increased gold production of 7,500 ounces per year. The payback for the project is estimated to be around one year.This paper describes the evolution of the project from bench scale testing to commissioning. Also, the operational and economic impacts on down stream processing are highlighted"

Jan 1, 1998

By D. Farrish, W. A. Grell

"IntroductionMost base metal mines sell their concentrate to a custom smelter. The two parties concerned therefore draw up a contract which would detail the conditions under which concentrate sales will take place. The contract will identify treatment and marketing charges (including escalations), deductions for metal losses in the smelter, pricing formula, timing of payments, penalties for deleterious elements, etc.An understanding of the smelter contract is important to the mineral processor, for it will determine how he operates the plant to maximize economic return.Description of Contract ClausesUsing copper concentrate as an example, the smelter contract generally contains the following three basic charges:I. Metal Deductions- as the smelting process does not recover all the metal contained;2. A Smelting Charge- expressed per ton of material to cover costs on the bulk material such as receiving, unloading, thawing in winter, sampling, roasting to drive off sulphur, smelting through the matte and blister stages to recover mostof the copper and precious metals;3. A Refining Charge- expressed per pound of copper.The following is a review in some detail of a number of clauses which could be considered typical of a treatment and marketing type of copper concentrate sales contract. Most normal considerations in an agreement could be covered by the following types of clauses.Terminology- covers definitions, units of measurement to be used (e.g. short tons, troy ounces, etc.), currency (Canadian dollars). The term ""unit"" may be defined - l OJo of a ton of concentrate, e.g. one unit of copper means 20 pounds of copper per short ton of concentrate."

Jan 1, 1989

By J. Butra

The underground research presented in this paper was carried out in the two Polish copper mines: Rudna and Polkowice-Sieroszowice. The aim of the research was to determine stress field parameters. The measurement method and measuring positions are described as well as the measuring technique adapted to the geological and mining conditions of the Rudna mine and the Polkowice-Sieroszowice mine. The identified values and directions of principal stresses and horizontal stresses and their importance for optimization of mining operation and safety improvement are discussed.

Aug 1, 2013

By B. Caldwell

"The CompanyCardinal River Coals is jointly owned by Luscar Ltd. and the Consolidated Coal Company of Canada (Consol). The Luscar mine is operated by Luscar Ltd. and is located 40 km south of Hinton near Cadomin, Alberta (Fig. 1). The plant sits on the old townsite of Luscar, Alberta, which was founded in order to develop the coal in 1912 (Fig. 2). Initially, the coal was mined by Luscar Ltd. for heating and steam generation and used quite heavily by the railways for their steam locomotives. In 1955, the mine was decommissioned as the demand for coal for tl1ese purposes had dropped off. In 1969, the mine was re-established by Cardinal River to provide metallurgical coking coal for its customers in Japan. The coal is mined from the 13m thick Jewel Seam by open pit methods at a 10 to 1 stripping ratio. The run-of-mine coal is then cleaned to meet customer demands.The PlantThe clean coal preparation facilities at Cardinal River were extended in 1980 in order to increase the feed rate from 450 t/h to 800 t/h. The extension is a separate plant which can be operated on its own or in parallel with the old plant. In addition, modifications have been made to the fine coal circuit (hydrocyclones added), the coarse refuse circuit, (refuse bucks replaced by a refuse conveyor which backfills a pit), and the fine refuse circuit (solid bowl refuse centrifuges, refuse classifying cyclones, and hydra-rake thickener no longer utilized) since the plant was built in 1969. The plant production of 3 M t per year with a yield of 78% is achieved by first screening and breaking the run-of-mine material to a top size of 1 ½ in. The feed is then slurried, sized, and processed in three different washing circuits. The washed coal is mechanically dewatered, thermally dried, and then stored in a 14 500 t capacity silo or on a 300 000 t stockpile. The fine refuse is thickened and pumped to the same pit to which the coarse refuse is being conveyed"

Jan 1, 2000

By D. Tao

The adverse effects of clay particles on coal and mineral processing processes such as gravity separation, flotation, filtration, and thickening are well known in the mining industry. In particular, the presence of ultra-fine clay particles deteriorates froth flotation performance, which has been attributed largely to slime coatings that inhibit bubble attachment and to adsorption of the frother and/or collector by the clay particles. The present study was conducted to evaluate the performance of clay binding agents developed by Georgia-Pacific Resins, Inc. in enhancing coal and mineral flotation performance. Mechanical and column flotation tests were carried out using coal and potash samples. Process parameters investigated include slurry solids percentage, impeller rotation speed, binder dosage, collector dosage, etc. Flotation results show that use of GP reagents significantly enhanced flotation efficiency under different conditions. The required binder dosage and conditioning time was about 1 lb/t and 0.5-1 min, respectively. More significant improvements in process performance were observed at higher solids percentage and higher impeller rotation speed.

Jan 1, 2006

By W. G. Jewitt

THE Box mine, situated in Saskatchewan on the north shore of lake Athabasca, is unique in two respects. It is the first and, so far, the only gold mine in Saskatchewan, and it is the only gold mine in Canada to employ a large-scale forced caving system as the main mining method. Discovered in 1934 by Tom Box, an Edmonton prospector, its subsequent history, while breaking no records for speed, has been one of steady and more or less normal development. Camp and plant are situated close to the shore of Beaverlodge bay, sorne 50 miles east of the Saskatchewan-Alberta boundary and 35 miles south of the north boundary of the Province. The railhead at Waterways, Alberta, is about 220 miles to the southwest. Prince Albert lies some 450 miles to the south. The surrounding country presents a rather rugged variation of the usual Precambrian topography, with hills rising five to six hundred feet above lake Athabasca. The numerous lakes and islands, together with the wide expanse of lake Athabasca, compose an attractive scene, at least in the not over-long 'open water' season. The winters are long but not extremely cold, judged by prairie standards. The small lakes break-up around May 20th and the 'freeze-up' stops navigation early in October. Though apparently remote, the Box mine is fortunate in having reason-ably cheap transportation from Edmonton. The 300-mile railway from Edmonton to Waterways is the most expensive section, the rate for 1st class freight being $1.70 per hundred pounds and for 5th class freight $0.77 per hundred. Freight from Waterways to the mine, approximately 140 miles down the Athabasca river and 90 miles along lake Athabasca, is delivered by barges and tugs for 50 cents per hundred pounds. All freight is delivered during the 'open water' shipping season, which lasts from about .Tune 7th to October 7th. In normal years, barges are loaded to 3 to 3 1/2feet draught up to September 1st. After that date, and earlier in dry years, shallow water at Waterways reduces the barge loads. Barges of 100 to 200 tons capacity handle all mining freight, including pieces up to 15 tons in weight, without undue difficulty.

Jan 1, 1940

By Y. Chengxian

Many factors about the HIC (hydrogen-induced cracking) resistance of pipelines are discussed in this paper. The main factors that influence the ability of HIC are environmental and material factors. The chemical compositions, non-metal inclusions and microstructure are discussed in detail, while a group of tests on HIC resistance are done according to varying C, S, Mn and P contents in pipeline steels, different experiment time and different strength to the coupon. It is concluded that decreasing the amount of C and S can obtain good HIC resistance; the test time has an effect on the different microstructure of X70; microstructure is the most sensitive factor for the initiation processes of HIC.

Jan 1, 2005

By R. D. Brown

For the first time in years, the spring budgets of federal and provincial governments have not brought down major new proposals affecting the tax burdens of the mining industry in Canada. It seems appropriate to use this unaccustomed period of tranquility to set out an extremely abbreviated summary of the principal features of the federal and provincial income and mining tax rules affecting the mining industry.

Jan 1, 1977

By R. W. Wein, L C. Bliss

Northern ecosystems are dominated by a harsh physical environment which dictates a need for biological adaptation. As yet, it is unknown just how these adapted plants and animals will tolerate industrial development. Our work, sponsored by university, government and industry, is part of an effort to evaluate this developmental impact. Our present studies and the results to date will be discussed. Other problems to which the environmental student may address himself in the future to ensure against environ-mental degradation will be suggested.

Jan 1, 1971

By M. Reda

Because of the adverse environmental effect of Chromate, Molybdate ions had been investigated as replacement for Chromate and the results had shown not to be encouraging. Film deposited from peroxopolymolybdate (from reaction of Molybdenum meta, with excess Hydrogen Peroxide), are more robust than that deposited from molybdate solutions. This was shown to be due to higher fraction of Mo (IV) and Mo (V) that form from Mo (VI) in the peroxopolymolybdate deposited film than the film deposited from Molybdate solutions. The peroxopolymolybdate film contains 40% un-hydrated molybdic acid, tetraperoxodimolybdate and tetra peroxo tetra molybdate. The protective properties of peroxopolymolybdate were shown to be due to the effectiveness of the un-hydrated molybdic acid.

Jan 1, 2010

By D. W. Li

Due to the ultrasonic testing and mechanical wind speed sensor have high requirement for the environmental of the coal mine, the charge induction wind speed detection method based on wavelet analysis is proposed. The same wavelet disturbance detection method is used at a fixed distance to obtain an induction signal to obtain a pass time, and then calculate the magnitude and speed of the wind. Simulation and verification experiments show that the method has application across a wide range of test speeds (up to 60 m/s). The metal probe causes little pipeline flow field interference. The method is particularly well-suited to dusty environment, and does not cause dust deposition through long-term operation. It can be widely used in coal mines for point wind speed continuous online testing.

Aug 1, 2013

By Y. Chengxian, F. Yaorong, Xinzhe. L.

Many factors about the HIC (hydrogen-induced cracking) resistance of pipelines are discussed in this paper. The main factors that influence the ability of HIC are environmental and material factors. The chemical compositions, non-metal inclusions and microstructure are discussed in detail, while a group of tests on HIC resistance are done according to varying C, S, Mn and P contents in pipeline steels, different experiment time and different strength to the coupon. It is concluded that decreasing the amount of C and S can obtain good HIC resistance; the test time has an effect on the different microstructure of X70; microstructure is the most sensitive factor for the initiation processes of HIC.

Jan 1, 2005

By Z. F. Zhou, X. Y. Zhou, V. G. Papangelakis, Z. D. Jankovic, S. M. Ulyanov, S. N. Lvov

Recently developed flow-through electrochemical techniques (1,2) were employed for measuring pH in high concentration aqueous solutions and geothermal brines. The pH values of (1) 5.0 mol kg-1 NaCl + x mol kg-1 HCl, (2) 3.0 mol kg-1 of NaCl + 0.5 mol kg -1 of KCl + 1.0 mol kg-1 of CaCl2 + x mol kg-1 HCl (x < 0.1 mol kg-1), and (3) mixtures of Al2(SO4)3-H2SO4-H2O, MgSO4-H2SO4-H2O, and NiSO4-H2SO4-H2O solutions have been measured at temperatures from 100 to 280°C. The obtained experimental data and their thermodynamic analysis demonstrated that the electrochemical system can be used for on-line pH monitoring of high concentration aqueous solutions with an accuracy of ±0.1-0.3 pH units over a wide range of temperatures. Greater deviation exists in real laterite leach solution measurements due to in situ precipitation of Na-alunite. The system is excellent for research and process development work. Further work is needed to ensure robust operation under pressure leach conditions of laterites.

Jan 1, 2004

By W. S. Hargratt

THE present era of exploitation of the Little Long Lac and Sturgeon River areas commenced in 1925, when Beardmore Gold Mines started development of what is now the property of Northern Empire Mines. A shaft was sunk in 1927-28 and a very limited amount of underground work was carried out, following which the property was shut down. It remained idle until 1932, when Empire Star Mines, a Delaware Company, optioned the property. This Company formed the Northern Empire Mines Company, Limited, to operate the mine, and immediately instigated an aggressive programme of surface and underground development. By the summer of 1933, sufficient ore was indicated to justify the installation of a small mill. The decision was also reached to bring in electric power. A power-line was built from Hydro, the Ontario Power Commission&apos;s development on the Nipigon river, to the mine, a distance of approximately 50 miles. This work was entirely financed by Northern Empire Mines. Mill construction was commenced in October, 1933, and completed by March, 1934, thus making this mine the first producer in this district.

Jan 1, 1940

By A. E. McIlhinney, I. E. Puddington, C. E. Capes, A. F. Sirianni

"Two main problems are associated with the removal of pyritic sulphur from coals. The first is due to the fine state of dissemination of pyrite, which requires grindin1 to a very fine size to accomplish liberation. The second problem is caused by the similar surface chemical characteristics of coal and pyrite, which complicates separatio11 methods based on this property. In the work described here, the problem of fine particle size was overcome by using the selective oil agglomeratioa method developed at the National Research Council of Canada. Recovery of more than 90% of the combustible values was possible, even with particles only a few microns in diameter. Experiments using conventional chemical depressants for pyrite met with little success. It was found, however, that pyrite may be rejected during coal agglomeration through treatment with the iron.oxidizing bacteria, thiobacillus-ferrooxidans. The conditions for maximum pyrite separation are described and possible mechanisms by which the bacteria act are discussed."

Jan 1, 1973

By E. M. Timoshenko, A. V. Tarasov

The results of laboratory, bench-scale and semi-commercial investigations of a method for adding surfactant (technical-grade lignosulphonate) to the process of pressure leaching of nickel-containing pyrrhotite concentrates have been discussed. Lt has been demonstrated that feeding of technical-grade lignosulphonate distributed along the length of an autoclave ensures a reduction in its requirement by a factor of 1.5 to 2 as compared with single-point feeding; it also results in a decrease by 5% in the unit requirement of metallized iron-bearing precipitator in the process of non-ferrous metals precipitation and reduces by 0.05 to 0.1% (abs.) the nickel and copper contents in the tailings of the given process. Technical solutions have been proposed for commercial introduction of the process.

Jan 1, 2004

By A. V. Tarasov

There are still a number of copper smelters in the world using the roasting and smelting process flow diagram for treating sulphide raw materials. The technical, economic and environmental performance indicators of such operations are inferior to the respective indicators of advanced processes. First of all with respect to copper and sulphur recovery: 95% and 75% as compared with 98% and over 90%, respectively. Based on the studies of the single-stage smelting process to produce white metal and blister copper conducted during recent years an analysis of the feasibility of roastingsmelting technology improvement was carried out in the Gintsvetmet Institute to substantially increase the copper and sulphur recoveries. On the basis of this analysis, it was proposed to modernize the technology and equipment within the framework of the existing process flow-sheet. The proposed modernization implies an increase in the roasting temperature; higher desulphurization degree in the process of roasting; a number of modifications in the roaster design depending on the particular conditions of a given operation; addition of lime flux to the feed charge to roasting; and transition to combined calcium-silicate smelting slags. The metallurgical and energy computations made have indicated that the proposed modifications of the technology will improve the copper and sulphur recovery up to 98% and 90%, respectively. The required capital investments have been estimated using as an example a particular copper smelter, the payback period determined taking into consideration additional output, fuel saving and a reduction in fines for sulphur emissions. For comparison, the capital cost of a smelter modernization is given for change-over to basically new autogenous Ausmelt, Outokumpu and V anyukov smelting technologies.

Jan 1, 2007

By P. J. Le Roux

"Mining worldwide and definitely in South Africa, is constantly under pressure to reduce its cost structure so as to sustain profitability. In underground gold mines where an open stope mining method is employed, dilution often has a significant effect on the viability of sustaining profits. Target Mine practices Open Stope mining Method and it was found that in some open stopes dilution was in excess of 10%, which has a significant impact on the sustainability of the mine.Dilution in excess of 10% can result in the reduction of the recovered grade from 5,5 to 4,5 grams per ton (g/t). The reduction of 1 g/t in recovered grade results in a potential loss of about ZAR21 Million per month bases on a gold price of ZAR240 000 per kilogram. Based on Life of Mine projections the potential loss of income could be as much as ZAR3,3 Billion. A reduction in dilution would have the opposite effect. There are a number of factors which affect dilution of which falls of ground in open stopes is a major contributor. The falls of ground can be attributed to a number of factors such as beam failure as a result of a larger than normal expected roof area (hydraulic radius too large), poor ground conditions, and poor blasting. The cost of damage to or loss of trackless equipment as a direct result of the falls of ground in open stopes, is very significant. The review of financial figures has indicated that this could be as high as ZAR491 million. This combined with the added cost of transport, hoisting, secondary blasting, milling and plant treatment costs of ZAR293 results in an estimated opportunity loss of ZAR784 million.Currently there is a significant amount of data available in the mining industry which could be effectively used to develop suitable back analysis techniques but to date this has not been used effectively. If dilution can have such an impact on current and future mining ventures then the optimization of back analyses for the prediction of dilution in open stoping could assist significantly in the reduction of dilution in massive open stopes. Rockmass classifications, geotechnical information, blast techniques, blast design, the stress strain environment and hydraulic radius all have an effect on, or play a role in the evaluation of dilution. Each of these factors will be taken into consideration to ultimately determine a measurable or calculated percentage of dilution in massive open stopes.The amount of overbreak in an open stope can be determined by subtracting the planned stope volume in m3 from the actual measured final stope volume in m3, which is obtained from the CMS (cavity monitoring system). This is in turn divided by the planned stope volume in m3 to determine the percentage overbreak. The CMS wireframe is imported into the geological model and its grade re-evaluated. From this the actual percentage dilution for this open stope can be determined. The dilution obtained can result in a major reduction of recovered grade for the open stope, but can also increase the recovered grade. The latter is normally the exception rather than the rule.When analysing data from Target mine the following was achieved:• Using 11 years of data a method of measuring and predicting the percentage dilution in open stoping was developed. This took into account rock mass quality, stress-strain state, and the hangingwall hydraulic radius (size of stope hangingwall exposed).• Implementation of this prediction method resulted in a reduction in falls of ground in open stopes. The benefit of this was a reduction in the damage to mechanised equipment resulting from less falls of ground which had a positive effect on the profit margins of the mine. As a direct result the recovered grade from the open stopes increased due to the reduction in the amount of dilution.• A design criterion, Dilution Stress-Strain Index (DSSI), was developed which allows the user to calculate, with certainty, the stability of the open stope and determine if m"

Jan 1, 2015

By Jan W. Merks

The objective of metrology in mineral exploration is to derive unbiased confidence limits for masses of metals contained in reserves and resources. Sets of test results for gold and silver determined in pairs of interleaved bulk samples give unbiased confidence limits for the central value of each metal. The same sets of test results show how to verify spatial dependence by applying Fisher?s F-test to the variance of a set and the first variance term of the ordered set. A significant degree of spatial dependence gives a higher degree of precision for the central values of gold and silver. Plotting variance terms of an ordered set against the variance of the set and its lower limits of asymmetric 99% and 95% confidence ranges gives a sampling variogram. Sampling variograms put in plain view where spatial dependence in sampling units or sample spaces dissipates into randomness. The application of statistical methods to test results for sets of ordered core samples within boreholes, and for sets of ordered ore volumes within profiles, plays an important role in defining reserves and resources.

Oct 1, 2009