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By Yuanming Pan, Brett Rogers, Baoquan Hu, Gary Yeo, Christine Austman

The nature and distribution of radiation-induced defects (RIDs) in quartz from the Maw Zone, a yttrium- and rare-earth-element-enriched sandstone breccia complex exhibiting intense hydrothermal alteration, have been investigated by electron paramagnetic resonance (EPR) spectroscopy. EPR spectra show that detrital quartz in sandstone, from five diamond drill holes intersecting the Maw Zone and one above the crest of the so-called Quartzite Ridge, contain only background-level RIDs, indicating that Ubearing fluids were absent in this area. However, close to the sandstone-basement unconformity, in hole WR-194 immediately west of the Quartzite Ridge, the concentration of RIDs in detrital quartz is significantly above background but at least an order of magnitude lower than those at the Key Lake and McArthur River deposits. Widespread drusy quartz at the Maw Zone, which signifies intense hydrothermal alteration, is associated with hematite-, sulfide- and carbonate-bearing mineral assemblages, which exhibit complex crosscutting relationships. EPR spectra of drusy quartz in all three types of mineral assemblages are low in RIDs as well, supporting the EPR evidence that fluids at the Maw Zone did not carry significant U. These EPR results suggest that, in spite of intense hydrothermal alteration and favorable structural geology, the Maw Zone is unlikely to host any significant U mineralization. Moreover, this study shows that the EPR technique is potentially a useful exploration tool, capable of determining whether individual alteration zones in the Athabasca Basin were associated with U-bearing fluids or not.

Jan 1, 2013

By F. E. Patton

"IntroductionAT NORANDA, the strength of the ore and wall-rocks per-mitted mining in large open stopes. While some of the orebodies were small and could be mined out in one stope, in most cases their size was such that it was essential that ore pillars be left during the first stage of mining. In these cases, backfilling has been necessary for ground control and to facilitate the later recovery of the ore in these pillars.This paper discusses the development of the •backfill and •its use in pillar recovery.GeologyThe ore bodies at Noranda occur as replacement deposits in a block of rhyolite flows and breccias, bounded on the north by the Horne Creek fault and on the south by the Noranda Andesite fault. Mineralization consists of pyrite, pyrrhotite, magnetite, chalcopyrite, sphalerite, gold, and various tellurides.The main orebody is a massive sulphide deposit designated the 'H' orebody. It is elliptical in plan, measuring roughly 400 feet by 800 feet, and is divided into two zones -Upper H, extending from surface to the 1,500-foot level, and Lower H, from the 1 ,500-foot level to just below the 3,000-foot level.Mining MethodsOpen stope mining in both Upper H and Lower H zones has been fully described in previous publications (1). A brief review only of the mining methods will be given here."

Jan 1, 1952

By C. Schlumberger

INTRODUCTION The object of the present paper is to discuss, from a geological point of view, the practical results obtained by the authors with the method of the 'resistivity map of the subsoil' in the study of various mining problems. Some of the studies described date from 1920, 1922, and 1923. They are, therefore, quite old, at least as far as geophysical research is concerned (1). Others, on the contrary, are very recent (2). We shall deal only very briefly with the theoretical and technical sides of the processes employed. This paper has, essentially, a practical purpose, and it has seemed unnecessary to enter into a detailed discussion of the methods. Such a discussion cannot be presented without introducing ,quite. Complex considerations both of mathematics and experimental physics, which interest only the geophysicist: whose work is highly specialized.

Jan 1, 1931

By M. Ye. Shulgina, M. L. Bolotin, S. A. Prokopev, Ye. S. Prokopev

Iron ores concentration at Russia’s operations is carried out using conventional flow sheets. They comprise the two-four stage grinding followed by one-two stage magnetic separation. This results in the maximum recovery of magnetite to concentrate and the tailings generation. The final concentrate is generated only during the last stage of magnetic separation. Technologically, this flow sheet layout is not effective at recovering the liberated magnetite grains during grinding to the resulting concentrate. Advanced models of magnetic separators do not allow for the selective separation of the tailings and the portion of the resulting iron ore concentrate. Magnetic product which is the ore mixture of the liberated magnetite grains, high grade and low grade intergrowths is directed to the next grinding stage. In this case, regrinding of the liberated magnetite occurs. In addition, the performance of hydrocyclones during classification in closed grinding circuits is poor. Their classification efficiency does not provide the material separation in accordance with the size. In this case, simultaneous separation in accordance with the density occurs. The quartz particles with the size of 300 mm have similar velocity and trajectory like the particles of magnetite with the size of 60 mm. As a result, light and coarser intergrowths report to the overflow and free heavy magnetite grains report to underflow and return to regrinding (“the density effect”). This resulted in a significant increase of a mill circulating load, the decrease in the feed throughput and higher power consumption. In this connection, the development of iron ore concentrate stage recovery with the focus on gradual liberation of the intergrowths is getting much attention. Gravity concentration technique, particularly, spiral separation is effective at solving the problem of stage recovery not only the dump waste product but also high grade magnetite concentrates at the early concentration stages. This can be attributed to a significant difference in magnetite (4.9-5.2 g/cm3) and host minerals (quartz 2.7 g/cm3) densities, which is the principal during gravity concentration. The test work on concentration of various products samples from current operations (the mills discharges, concentrates from various stages of wet magnetic separation and cyclones underflows) was carried out. Spiral separators SV-500 and ShV-500 manufactured by Spirit LLC were used for the test work. High grade iron ore concentrate (69.05% Fe) was generated during primary wet magnetic separation concentrate concentration using a spiral separator. During the concentration of mills discharges the content of iron in the resulting concentrates and middlings of wet magnetic separation II stage was 64.5% and 64.6%, respectively. The recovery of iron to the concentrates of spiral separation was 33.6-42.0%. The studies presented demonstrate that by using spiral separation for iron-bearing ores concentration, you can separate magnetite liberated grains at the early concentration stages, decrease their regrinding and circulating loads in grinding circuits. This process is able to improve the overall recovery and economics of iron ores concentration process.

Jan 1, 2016

By M. Ye. Shulgina, M. L. Bolotin, S. A. Prokopev, Ye. S. Prokopev

Iron ores concentration at Russia’s operations is carried out using conventional flow sheets. They comprise the two-four stage grinding followed by one-two stage magnetic separation. This results in the maximum recovery of magnetite to concentrate and the tailings generation. The final concentrate is generated only during the last stage of magnetic separation. Technologically, this flow sheet layout is not effective at recovering the liberated magnetite grains during grinding to the resulting concentrate. Advanced models of magnetic separators do not allow for the selective separation of the tailings and the portion of the resulting iron ore concentrate. Magnetic product which is the ore mixture of the liberated magnetite grains, high grade and low grade intergrowths is directed to the next grinding stage. In this case, regrinding of the liberated magnetite occurs. In addition, the performance of hydrocyclones during classification in closed grinding circuits is poor. Their classification efficiency does not provide the material separation in accordance with the size. In this case, simultaneous separation in accordance with the density occurs. The quartz particles with the size of 300 mm have similar velocity and trajectory like the particles of magnetite with the size of 60 mm. As a result, light and coarser intergrowths report to the overflow and free heavy magnetite grains report to underflow and return to regrinding (“the density effect”). This resulted in a significant increase of a mill circulating load, the decrease in the feed throughput and higher power consumption. In this connection, the development of iron ore concentrate stage recovery with the focus on gradual liberation of the intergrowths is getting much attention. Gravity concentration technique, particularly, spiral separation is effective at solving the problem of stage recovery not only the dump waste product but also high grade magnetite concentrates at the early concentration stages. This can be attributed to a significant difference in magnetite (4.9-5.2 g/cm3) and host minerals (quartz 2.7 g/cm3) densities, which is the principal during gravity concentration. The test work on concentration of various products samples from current operations (the mills discharges, concentrates from various stages of wet magnetic separation and cyclones underflows) was carried out. Spiral separators SV- 500 and ShV-500 manufactured by Spirit LLC were used for the test work. High grade iron ore concentrate (69.05% Fe) was generated during primary wet magnetic separation concentrate concentration using a spiral separator. During the concentration of mills discharges the content of iron in the resulting concentrates and middlings of wet magnetic separation II stage was 64.5% and 64.6%, respectively. The recovery of iron to the concentrates of spiral separation was 33.6-42.0%. The studies presented demonstrate that by using spiral separation for iron-bearing ores concentration, you can separate magnetite liberated grains at the early concentration stages, decrease their regrinding and circulating loads in grinding circuits. This process is able to improve the overall recovery and economics of iron ores concentration process.

Jan 1, 2016

By K. A. Foxford, D. A. Polya, R. P. B. Hebblethwaite

"Abstract-A variety of techniques for interpreting systems of mineralized echelon veins is discussed using examples from Panasqueira and SW England. As aids for exploration and mine planning, and as a tool for ore reserve evaluation, particular emphasis is placed upon establishing vein morphology in the third dimension, and upon understanding vein dilation and propagation histories. Special attention is also placed upon investigating vein thickness and spacing relationships, and upon understanding vein segmentation. The relevant data for these techniques are all readily obtainable from stope and core sources.The vein systems described were produced in host-rock sequences that underwent incremental dilation in response to fluid overpressures, and individual veins display evidence for mineral infilling synchronous with their propagation. Echelon vein geometries resemble those reported from igneous dikes and sills: vein walls are stepped and veins are divided into segments arranged in echelons. Changes in vein geometry, from arrays to composite structures, reflect both the evolution of the vein system with time, and the changes occurring between the margins (arrays) and core (composite structures) of the system. These characteristic morphologies can be used to infer vein propagation and fluid injection trends, proximity of neighboring veins, and the shape of the system as a whole. The techniques are applicable to systems of echelon veins produced under tensile conditions in rocks where faults were absent at the time of vein formation, and where subsequent deformation has been minimal. Further work is required to assess the application to echelon vein systems formed within more complex tectonic regimes."

Jan 1, 1995

By Y. Rama Murthy, Amit Ranjan, Pankaj Satija, Sunil K. Tripathy

"Chromite ore is one of the essential raw materials for ferroalloy and steel industry. Boula-Nuasahi belt of Sukinda region, Odisha, is the only resource of chrome ore in India. The Indian deposits are typically characterized as ferruginous and siliceous type ores. Chrome ore is generally mined by open cast mechanized mining method in these areas. The run-off-mine (ROM) ore from the various mines is sent to beneficiation plant via stack yard for further up gradation. The chrome ore beneficiation plant (COB) has two major circuits: comminution (feed preparation) circuit and beneficiation circuit. In the comminution circuit, the ore is reduced to <1 mm size ( for complete liberation of chromite) from -220 mm size in stage wise crushing (primary and secondary crusher) followed by screening and single stage grinding in a ball mill. Fraction having size <1 mm is further upgraded in the beneficiation circuit to produce three different concentrates having specific chemical composition and Cr: Fe ratio. The beneficiation plant is a complex circuit comprising of combination of unit operations (spiral concentrator, Floatex density separator, hydrocyclone, wet shaking tables). In the recent years the overall performance efficiency (grade and recovery) of the beneficiation circuit got affected with numerous changes in the run-off-mine ore quality (physical and chemical), mineralogical composition, etc.In this article, attempts made for improving the performance of chrome ore beneficiation circuit is discussed. The approach adopted and practical problems encountered while the process were also highlighted. The results of the trials has shown an improvement in the performance of the cyclone (d50 : 56 µm – 40 µm) and chromite losses into tailing to <12%.INTRODUCTIONChromite has a wide range of application, from refractories to metallurgical industries, and from chemical to non-ferrous alloy industries. Chromium ore (Fe2+, Mg) [Cr, Al, Fe3+]2O4) occurs exclusively in rocks formed by the intrusion and solidification of molten lava or magma which is very rich in the heavy, iron containing minerals such as pyroxene and olivine. With the richness of silica and iron, the chrome ores are broadly classified as siliceous type and ferruginous type. Pure chromite with composition FeCr2O4 is rare because magnesium usually substitutes for ferrous ion and aluminum and ferrous ion substitutes for chromium. Generally the associated gangue minerals are talc, quartz, hematite, goethite, limonite, gabro, serpentine, anorthosite, dunite, pyroxinite, etc. Around 96% of the chromite ore production is consumed for metallurgical applications of which 94% is converted into different grades of ferrochrome i.e., high carbon ferrochrome and charge chrome as shown in Figure 1. Stainless steel being the leading consumer of ferrochrome, any change in the dynamics of the stainless steel industry impacts overall chrome ore demands significantly."

Jan 1, 2016

By K. A. Foxford, D. A. Polya, R. P. B. Hebblethwaite

"A variety of techniques for interpreting systems of mineralized echelon veins is discussed using examples from Panasqueira and SW England. As aids for exploration and mine planning, and as a tool for ore reserve evaluation, particular emphasis is placed upon establishing vein morphology in the third dimension, and upon understanding vein dilation and propagation histories. Special attention is also placed upon investigating vein thickness and spacing relationships, and upon understanding vein segmentation. The relevant data for these techniques are all readily obtainable from stope and core sources.The vein systems described were produced in host-rock sequences that underwent incremental dilation in response to fluid overpressures, and individual veins display evidence for mineral infilling synchronous with their propagation. Echelon vein geometries resemble those reported from igneous dikes and sills: vein walls are stepped and veins are divided into segments arranged in echelons. Changes in vein geometry, from arrays to composite structures, reflect both the evolution of the vein system with time, and the changes occurring between the margins (arrays) and core (composite structures) of the system. These characteristic morphologies can be used to infer vein propagation and fluid injection trends, proximity of neighboring veins, and the shape of the system as a whole. The techniques are applicable to systems of echelon veins produced under tensile conditions in rocks where faults were absent at the time of vein formation, and where subsequent deformation has been minimal. Further work is required to assess the application to echelon vein systems formed within more complex tectonic regimes."

Jan 1, 1995

By L. J. Friedman

The recovery of sulfur dioxide from metallurgical gases for the production of sulfuric acid has been the primary means of reducing sulfur dioxide emissions from nonferrous smelters. Sulfuric acid has been produced from gas originating from fluid bed roasters, electric furnaces, reverberatory furnaces, flash smelting furnaces, Pierce Smith and flash converters, sinter machines, etc. The gas from each of these sources has a unique set of variables that affect the design and operation of the sulfuric acid plant. In addition, the sulfuric acid plant itself has been evolving, with new equipment designs and materials. This paper will review each of the unit operations in the gas cleaning and contact sections of the metallurgical sulfuric acid plant, discussing various equipment designs, materials and the handling of gas stream variables and impurities. The paper updates to 2007 previous works on metallurgical sulfuric acid plants by the authors, and analyzes new equipment and systems, including: FRP or alloy quench systems, alloy converters, towers and pump tanks, heat recovery systems, high efficiency mist eliminators, tower packing, etc.

Jan 1, 2007

By M. Massinaei

Recently constructed circuits have included multiple stages of columns in a variety of applications, from roughing to cleaning. The Miduk copper concentrator (in south-eastern Iran) is one of the unique mineral processing plants which use column flotation cells as rougher. As the bulk of final concentrate is produced by rougher columns, optimized metallurgical performance of these cells is crucial. This paper will present the study and optimization of, a froth washing system of columns. For this purpose, the cross-sectional area of orifices was increased and their orientation altered. Concentrate assay for copper and silica, in addition to bias rate were found to be the assessment criteria. Modification of the wash water system resulted in increasing the purity of rougher and final concentrate. Negative bias and short-circuiting of wash water into the concentrate launder were the main causes of improper froth zone washing in the former system.

Jan 1, 2007

By Dean Gerhardt

Why the need for proactive loose detection? ?? Past history of ground falls in Saskatchewan mines prompted research into new techniques for ground control. ?? Traditional tools for ground assessment (i.e. visual inspection, sounding with scaling bars) are not proactive and can often be time consuming. ?? Need existed for a system that was non-evasive, time efficient, and could be managed by a single operator. Ground Penetrating Radar (GPR) immerged showing the greatest potential.

May 1, 2008

By M. Hozayen, E. S. Radwan, P. A. Nawrocki, A. Jebbouri

"A major geomechanical study was conducted for one of the UAE onshore oil fields with the purpose of studying reservoir rock properties and stress distribution, based on which a 3D coupled reservoir geomechanical model was built. This model was later used for wellbore stability analysis and for analyzing the effect of fractures on future reservoir production performance, including fracture deformation and permeability evolution occurring due to reservoir depletion and resulting changes in local stress field. The subject of this study was a complex fractured Upper Cretaceous carbonate reservoir characterized by high degree of heterogeneity, both vertically and laterally. Wellbore instability related drilling problems were encountered while drilling the wells in this field. The problems were mainly in drilling the horizontal wells, including breakouts and mud losses. Experimental results of laboratory tests are summarized in this paper whereas wellbore stability analysis and formulation of a 3D geomechanical model that was built for that purpose is summarized in a sister paper (Part II).A suite of tests reported includes tensile strength, uniaxial and triaxial compression and permeability under stress at simulated reservoir conditions. All tested rocks have been grouped into twelve test units and reservoir geology, rock types and challenges related to designing a viable sampling and testing program for a big reservoir are discussed first followed by sample selection criteria and details of the testing program. All test units showed brittle behavior at zero confinement and some samples showed similar behavior at low confining stresses. With confining stress increase, the behavior gradually turned to plastic but some samples showed features of ductile behavior even at low confinement.Obtained experimental data have been summarized in the form of strength criteria and correlations. The Mohr-Coulomb strength equations were obtained for each test unit and also for the averaged values. It was noticed that triaxial compressive strength (TCS) increases with decreasing porosity or increasing density but their influence on TCS is getting smaller with confining pressure increase. Good correlation of porosity and density with Young’s modulus, Poisson’s ratio, unconfined compressive strength (UCS), friction angle, cohesion and tensile strength has been noticed and there was an increasing trend between the confining pressure and TCS. Rock type (mud or grain supported) was not influencing the TCS as much as porosity and density and the two lithologies encountered affected TCS approximately in the same way. These results and correlations are summarized and explained in this paper. They were further used in the numerical modelling part (Part II) of this paper, Hozayen et al. (2015). It is also concluded that rock lithology is not a decisive factor and mechanical properties of tested rocks should be rather considered dependent on porosity and permeability. This helped greatly in reducing the number of tests that had to be performed."

Jan 1, 2015

By F. R. Nogas

"Because of the elements of uncertainty and instabilitp associated with single-enterprise communities, there is increasing interest in the alternatives to developing additional new communities of this nature. Gulf Minerals Canada Limited has chosen a unique alternative means to accommodate employees at a new uranium mine/mill complex at Rabbit Lake in Northern Saskatchewan. Gulf has adopted a fly-in program which moves their staff from a 450-mile radius, in and out of the on-site facilities, on a 7-day rotation."

Jan 1, 1976

By Pieter van Nierop

Outline ? What is gasification? ? Gasification Technologies ? Gasification ?The early years ? Gasification ? The last decade ? The Alberta Situation ? The Importance of Gasification in Alberta ? Polygeneration ? Development ? Conclusion

May 1, 2004

By J. Holtzhausen

"An analysis of operating costs for underground mining operations in the current global economic climate considers the financial burden for a ventilation system to be in vicinity of 30–50%. These operating costs are often overlooked by management teams in the greater scale of things when looking to save money in the procurement phase. This oversight to operational costs can be as little as the effective delivery of ventilating air to the work zone. One of the biggest opportunities for substantial savings and improvements can be realized in the selection of a quality vent duct that is suitable and fit for purpose. The key component to the selection process for quality products is a solid selection criterion that is followed during the tender process. This allows the management team to filter out unsuitable suppliers and products. The case study identifies some of the key components that were considered in the procurement and selection process for lay-flat ducting products. These included the characteristics and strength of the materials. The selection criteria also considered a ducted performance comparison that offers the best aerodynamic performance with some of the following components. • Airflow at Duct Face (m³/s or cfm), Fan Pressure (Pa), Air Power (kW or hp), Assumed Fan Efficiency, Annual Running Costs, K – Factor or Lambda, Leakage Factor, Joining Method and available Duct Lengths with weights. • Critical components considered were the current Testing standards available for: o Bursting Strength AS 4878.5, Mass AS 2001.2.13, Tensile Strength AS 4878.6, Tensile Strength AS 2001.2.3.1, Tear Strength AS 2001.2.10, Tear Strength AS 4878.7 • Other key considerations were: o Warranty Claim, Damage claims, Local storage / operations, community engagement and relationships, current testing data, previous issues, after sales service with technical assistance, etc. Hidden costs associated with product failures and operational stoppages are often not quantified during the tender process. Buyer beware. INTRODUCTION The largest constraint underground mining operations currently face are their operating efficiencies and electrical costs. The overall cost of an operations ventilation system and its components requires more focus to identify what opportunities exist to maximise efficiency and effectiveness. This tender process may not always be clearly understood and it should be broken down into fewer components to achieve quantifiable results."

Jan 1, 2019

By M. A. Cawley, J. W. Jordan

"IntroductionTHE ORE PILLARS in the lower ""A"" ore body of Waite Amulet Mines, Limited, can be divided into two groups, those mined in the open by sub-level blast-hole methods, and those to be mined .against coarse rock fill. Of the three pillars in the last group one has been mined and is dealt with in this paper. The method of mining pillars against coarse rock fill was suggested by the late Dr. Oliver Hall, who was Consulting Engineer for the Company when recovery of No. 2 East pillar was being planned.HistoryThe Waite Amulet mine is in northwestern Quebec, nine miles north of the town of Noranda. The property is approximately three miles long by one mile wide. The present Company, which was formed by the amalgamation of Amulet Mines, Limited, and Waite Ackerman-Montgomery Mines, Limited, commenced operations in the summer of 1937. In the fall of 1939 a new .flotation mill was erected with a capacity of 1,200 tons per day, which was increased to 1,800 tons per day in 1943. The mill is presently operated at 1,400 tons per day.To date, seven orebodies have been found, the major ones being Lower A, East Waite, and Waite. Three separate concentrates are produced, copper, zinc, and pyrite. Total tonnage mined to the end of 1954 from all orebodies has been 7,340,000 tons, which averaged 4.6 per cent copper, 5.3 per cent zinc, and 0.037 oz. gold and 1.27 oz. silver per ton."

Jan 1, 1955

By John Campbell, William Trahant

"Total Quality Management (TQM) is becoming a reality in the mining industry. Widely adopted in the manufacturing and services industries, TQM has become the operating style of choice in numerous mining companies across the Americas and Australia. Iron Ore Company of Canada, Inco, MSA, Graniterock, Magma Copper, and CRA&apos;s Hamersly Iron - all are pioneers of TQM. These companies and others are confronting the challenges of implementing TQM and are managing the changes required of their people and cultures. What these companies are doing, why they are doing it, and how they are successfully managing the changes are the subjects of this paper.Driving the need for change in these organizations are a host of issues, some of which all mining companies are facing. Requirements from customers for ISO 9000 certification is becoming one of the initial motivators for Total Quality Management. These standards, commonly used in manufacturing throughout the European Community (EC), emphasize quality in the processes that create outputs, instead of just the outputs themselves. Iron Ore Company of Canada, for instance, responding to the requirement of one of its customers, British Steel, has become one of the first mining companies to meet the quality standard. Suppliers who meet the standards are highly desirable to customers who are themselves operating under the ISO or their national quality guidelines."

Jan 1, 1995

By W. O. Karvinen

"In the Timmins area, a close spatial and chronological association exists between gold deposits and two major stratabound carbonate-rich members and related quartz-feldspar porphyries. Synvo/canic and metamorphogenic are the two main types of mineralization recognized. Synvolcanic ores include the stratiform quartz-ankerite ""veins"", pyritic carbonates and chert-carbonate-tuff sedimentary rocks and epigenetic ventrelated breccias and stringer zones. Metamorphogenic ores consist of quartz-carbonate fracture fillings in dilatant zones developed during various phases of regional deformation and metamorphism. They are classically epigenetic in character.The evidence suggests a primary syngenetic enrichment of gold on the ocean floor and in vent areas during submarine felsic volcanism and related exhalative-hydrothermal activity followed by further enrichment into quartz-carbonate stockworks during regional deformation and greenschist metamorphism.Although normally thin (a few hundred metres), carbonate members in Archean volcanic terrain represent intense hydrothermal activity which could have transported and enriched gold. They should be used to locate fossil vents and structurally favourable zones where economic concentrations of gold may be found."

Jan 1, 1982

By Hamid-Reza Manouchehri

Coarse particles flotation is controlled by detachment (particle hydrophobicity and flotation cell turbulence) For composite particles (the bubble may attach to good hydrophobic region, but the expansion of the three phase line of contact is limited. Hence, the equilibrium contact angle, characteristic of the hydrophobic region, may never be attained, and the force of attachment is decreased relative to that possible for homogenous hydrophobic surfaces.

May 1, 2013

By J. N. Hilton, D. Moffett, E. Barnes

"A recent pilot-plant program carried out at Rio Algom&apos;s Quirke uranium mine at Elliot Lake, Ontario is described. The goal of the research was the production of tailings basin effluents which were low in total radium-226. The process tested involved precipitation of radium with barium chloride and sedimentation in plastic-lined settling ponds. Adjustment of the tailings basin overflow from its normal value of pH 9.5 by addition of sulphuric acid to about pH 7.5 was found to give approximately a five-fold improvement in total radium-226 removal. A five-month demonstration test resulted in an effluent with a mean total radium-226 activity of44 pCi/L after 2.5 days settling time and 29 pCi/L after 5 days. The results from the demonstration program are used to propose a schedule of achievable total radium-226 activities where precipitation and sedimentation are employed. The maximum suggested values for 5 days nominal settling time are: 30 pCi/L in an annual mean, 45 pCi/L in a monthly mean. 60pCiIL in a weekly mean and 80 pCi/L in any single grab sample.IntroductionRadium-226 has been removed from effluents at the Elliot Lake uranium mines since the introduction of the first barium chloride treatment system in 1965. Current practice, which has changed little over the years, consists of radium-barium sulphate precipitation by the addition of a low do se of barium chloride to the clear overflow from the tailings basin(l·2l. Provision is made for the precipitate to settle in large natural or constructed ponds and lagoons. The residence time in these ponds, which depends on the site, ranges from 3 to 35 days, with varying degrees of efficiency being achieved."

Jan 1, 1981