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By Elizabeth Gardiner

Tailings and water management facilities are integral components of mine and mill operations. They must be managed for the long term to ensure that safe and environmentally responsible stewardship is achieved. The Mining Association of Canada (MAC) has developed and published two manuals to provide guidance to mining companies on sound practices for the safe and environmentally responsible management of tailings facilities: ???A Guide to the Management of Tailings Facilities; and ???Developing an Operation, Maintenance and Surveillance Manual for Tailings and Water Management Facilities. The Guides were designed to help companies develop and implement tailings management systems that include environmental and safety criteria, to improve the consistency of application of sound engineering and management principles to tailings and water management facilities through their full life cycle, and to demonstrate this to regulators and the public.

May 1, 2003

By C. J. Sullivan

"The outlook for supplying the world's metal needs in the next twenty-five years is good, although in several cases basic costs are likely to increase with rising demand. Metal prices calculated at a constant dollar from 1900 to the present show that for nickel, copper, silver, lead, zinc and tin, prices -and presumably production costs -fell from 1900 to the early 1930s. Since then, they have generally risen, apparently reflecting some depletion in relation to demand. This tendency has been accentuated since the post-World War II adoption of managed, full-employment, growth economics, which have resulted in a sharp escalation in world demand for metals. (Abandonment of such policies, apparently now under consideration in North America, would, of course, affect the pre-dictions of this paper.) Nevertheless, metal prices generally are still below those prevailing in 1900. Exploration potential exists for disseminated ores of many metals still thought of as characteristic of lode and vein deposits. These include uranium, silver, gold, tin and nickel and, to a lesser extent, lead and zinc. Considering the discovery potential for some principal metals in relation to expected demand and prices, I would tend to rate them as follows: molybdenum, zinc, lead, uranium, silver, gold, tin, nickel and copper."

Jan 1, 1970

By Sibabrata Patnayak

A major problem during shovel excavation in oil sand mining is the variability of material diggability resulting in varying mechanical energy input, cycle time, energy consumption, wear, and stress loading of shovel dipper-andtooth assembly. This variability greatly influences the mining equipment performance. Different approaches such as empirical ground classification systems, analytical methods, and performance monitoring that are used to determine diggability of groundmass are reviewed. It is concluded that the existing empirical diggability classification systems are site specific and mostly based on rock and therefore, cannot be used for shovel excavation in oil sands. The O&K wedge test is a simple and useful index test for establishing correlations between cutting resistance and geotechnical properties of coal and other soft rock overburden material. But this test, when performed on small size unconfined oil sand samples, may not give reliable indication of diggability because of the boundary conditions on the specimens. Digging predictions made using analytical and laboratory digging models need to be verified with performance monitoring data to better understand the digging effort in oil sands.

Apr 1, 2005

By A. C. T. Bigg

"The mineral potential of the Nanisivik area was discovered as far back as 1910 when a prospector of the Geological Survey of Canada, on an expedition under Captain J. G.Bernier, recorded a deposit of pyrite with minor sphalerite and galena. An outcrop of the present orebody was discovered by Texas Gulf Company in 1957. Subsequent drilling outlined the orebody consisting of 6,000,000 tonnes of ore containing 13 % Zinc and 1.5 % Lead. The orebody appears to have been formed by the filling of a limestone cavern with sulphides. The sulphide minerals consist of pyrite, sphalerite and galena. The limestone bedrock is mostly dolomite with some calcite and magnesite. A cutoff grade of about 6% Zinc has been calculated.In 1972 Mineral Resources International Limited took an option on the property. Upon completion of the feasibility study by Watts, Griffiths and McOuat, the then new independent project management group of Strathcona Mineral Services Ltd. were engaged to develop the project through the financing, construction and operating phases. Strathcona Mineral Services still manage the project from their head office in Toronto and through the Mine Manager and Department Superintendents at the Mine site. The interest for the project is presently split five ways: Mineral Resources International Ltd. 53.5 %, Government of Canada 18 %, Metallgesellschaft A.G. of Germany 11.25 %, Billiton B. V. of Holland 11.25 % and Texas Gulf Co. 6 %."

Jan 1, 1980

By Y. Shu, A. R. Laplante

"A laboratory Knelson Concentrator (LKC), 7.5 cm in diameter, was used to study the performance of a similar unit at plant scale, 76 cm in diameter, This paper reports on sampling and assaying procedures and problems, and discusses the performance of the plant unit.The sampling procedure was based on the extraction of large samples, 5-15 kg, and their complete processing with a LKC, to characterize size-by-size performance. The procedure yielded reliable estimates of overall gold assays, after blatant assaying errors were corrected. The plant centrifugal unit concentrate was sampled in situ, which yielded very erratic grades, with a large overall negative bias. Due to the very heterogeneous nature of the concentrate, which can be linked to flow patterns in the riffles of the unit, it is recommended that for future testwork, the concentrate be recovered separately, blended and then sampled.The plant centrifugal separator, when operated at a feed rate of 25 t/h, yielded total and free gold recoveries of 41 % and 62%, respectively. This is much lower than previously reported data, and suggest that at 25 t/h, the unit is overloaded. However, recovery did not decrease with time over a loading cycle of 2 hours, which suggests that present loading cycles, generally 1 hour, can be significantly increased. INTRODUCTIONThe study of gold gravity circuits is plagued with the statistical problem of determining the behaviour of particles occurring with a very low frequency. This problem becomes particularly acute with increasing particle size. For example, considering the average weight of a gold flake in the 840-1200 µm (20/28 mesh) to be about 5 mg (Banisi et al, 1991), a reasonably high grade feed of 10 git would require, for a relative error (standard deviation) of 10% on grade, 100 particles, that is 0.5 g of gold, or 50 kg of 840-1200 µm material (a Poisson distribution is assumed). Gy's formula, for the same data, yields a weight of 33 kg, with a shape factor of 0.1 and a size distribution factor of 0.5. Both results are comparable; to obtain the suggested weight of material, a stream containing 5% weight in the 840-1200 µm would require 1 tonne samples (of unsized material). The problem rapidly disappears with decreasing particle size. Still with Banisi et al's data, a gold flake in the 300-420 µm range averages 0.5 mg in weight; the same 10% error on grade corresponds to a weight of 5 kg. Gy's formula for the same size distribution and particle shape factors as above predicts a required mass of 1.4 kg. This would correspond to an unsized sample weight of 10 kg with 14% weight in the 300-420 µm, for example."

Jan 1, 1992

By L. D. Smith

"This paper examines the impact of the various assumptions that go into an economic evaluation, and shows how these can be combined to show an exciting result that may not really exist. An example of an embellished case (the kind that one frequently sees when projects are being promoted) is developed and the cumulative impact is analyzed to show the actual project underneath. The paper also points out some areas to watch for overly optimistic assumptions such as prices, inflation, and debt. The concept of a “bare bones” base case is proposed (constant metal prices, constant dollars, no inflation, no debt, no interest, on a project basis, after tax) as a common reference point.As well, the discount rate is examined as one of the fundamental means of reflecting risk in discounted cash flow evaluations. Current industry practice is discussed, and a methodology for the analysis of risk levels is proposed that assesses the constituent components of the discount rate: real interest, mineral project risks, and country risk."

Jan 1, 2002

By S. Banisi, M. Poorkani, M. Farzaneh, M. Askari

"At the Sarcheshmeh copper mine 40,000 t of ore per day with an average grade of 0.9 % Cu is ground to 70% passing 75 microns. Grinding is effected in 8 parallel lines of 8 x 5 m ball mills in a closed circuit with cyclones. The make-up balls are 80-mm forged alloy steel balls and the average ball consumption is 750 gh of ore ground. In order to optimize ball size distribution inside the mill, based on the previous investigation instead of using only 80 mm make-up balls a combination of 80 and 60 mm (75% to 25% by weight) ball charge was used in one of the mills. To evaluate the performance of three ball types namely forged alloy steel balls (A), ductile cast iron (C), high chromium cast iron (D) and also a combined (80 and 60 mm) charge of forged alloy steel balls (B), four identical parallel mills were charged accordingly. These four mills were sampled during a period of six months. The amount of material finer than 75 microns of cyclone overflows was selected as a criterion for the performance evaluation. It was observed that in a mill with the combined make-up balls the amount of fine produced was 4% higher than the other mills. The consumption of ball types A, C and D were 730, 710 and 534 g/t, respectively. The results of laboratory flotation tests showed that due to an improvement in the production of fines an increase of 1.4% in the overall copper recovery is obtainable. Due to the promising results, the new make-up ball regime was implemented in all mills in the plant.INTRODUCTIONThe Sarcheshmeh copper ore body which may rank as third or fourth largest in the world contains 1 billion tonnes averaging 0.90 % copper and 0.03 % molybdenum. It is located southeast of Iran and has been processing 40,000 t/d of ore since 1982. The mine produces 100,000 tonnes of copper and 2,200 tonnes of molybednite concentrate per year. After three stages of crushing, the ore with a F80 of 12.7 mm is fed to 8 parallel ball mills in closed circuit with cyclones to produce a product 70% finer than 75 microns. The concentrate of the first stage of flotation is reground and the tailing constitutes the main component of the plant final tailings. A concentrate with an average grade of 31% Cu is obtained after cleaning and re-cleaning stages. Total recovery of the plant varies between 83 and 87 % depending on the operating conditions and ore type."

Jan 1, 2002

By D. Ingram

"PRIMARY DUST COLLECTOR A. 42,000 CFM James Howden Fan Z-6 Size 3650 Fan Dia 40"" HP 75It was found that the fan was not large enough to remove the air that was displaced by the trucks dumping. So it was removed and an enclosure was installed to isolate the gyro from the rest of the building.B. FANSJames Howden Fans Model RPM 3500 Series 357 FW HP 10These fans were installed when the first dust system was put into operation. It was found that the high RPM and extreme fan wear caused a major maintenance problem. These fans were replaced with Chicage Blowers Model SWS1 RPM 1180 Dia 36"".DRY CYCLONE COLLECTORS A.,Three four foot rubber lined cyclones. Four six foot rubber lined cyclones.All under flow. Water is controlled manually and gravity flows to a central sump box. From there it flows to the grinding circuit in the Mill.Cyclone under flow product runs between 100 and 200 tons of dust per 24 hours with a screen analysis 30% + 400.The cyclone under flow product is diluted to about 3 to 4%. Solids total gallonage approximately 400.B.,Elbair Wet Scrubber125 HP RPM 56042,000 CFM,Model PX861The Elbair collects the total product from the discharge. Of the Cyclone fans the under flaw goes to the Mill - the Elbair discharges stack goes to atmosphere.The Elbair wet scrubber had to be redesigned in order to keep it in service."

Jan 1, 1976

By I. Dimitrov, S. R. McCutcheon

"Industrial-grade limestone is found in both the Lower Silurian La Vieille Formation and Upper Silurian LaPlante Formation of the Chaleurs Group in northern New Brunswick. Currently, between 150 000 and 200 000 tonnes of limestone are produced per year from the proximal facies of the LaPlante Formation at the Sormany quarry of Elmtree Resources Ltd., located west of Bathurst.The proximal facies of the LaPlante Formation was deposited on the margins of tectonically uplifted Ordovician terranes. This facies comprises stromatoporoidal-algal bindstone intercalated with wackestone, packstone, and floatstone in variable proportions. The distal facies comprises calcareous shale and minor limestone deposited deeper offshore.Folding and faulting related to Middle Devonian Acadian tectonism have caused an increase in the apparent thickness of the limestone sequences, especially adjacent to the regional Rocky Brook-Millstream fault. Structural and stratigraphic observations indicate that some of the limestone bodies in the area have been tectonically displaced from their site of deposition.A variety of prospecting techniques was used to locate new limestone resources, including geological mapping, airborne and ground electromagnetic surveys, and satellite remote sensing. Clastic rock units above and below the LaPlante Formation have distinctive properties that help to trace the intervening limestone along strike. Because of water-saturated glacial cover, thick vegetation, and the small size of targets, airborne geophysical methods did not prove effective in delineating limestone beds, but aeromagnetic surveys helped map the underlying clastic unit. The remote-sensing data and especially high-resolution digital elevation models helped in identification of karst topography related to limestone."

Jan 1, 2007

By A. W. Stradling, M. J. Fairweather

"The selective flotation of lead, zinc and iron sulphide minerals is key to the economic performance of concentrators treating zinc-lead ores. Diagnostic metallurgy is a tool to quantify mineral behaviour as a function of particle size and liberation. The result of such analysis may be used to select preferred strategies to improve metallurgical performance. The zinc flotation circuits at three Teck Cominco operations: Sullivan, Polaris and Red Dog are compared here. This paper analyses operating data from each of these circuits. The effects of mineralogy and performance by particle size are emphasized. Metallurgical performance at these three concentrators varies substantially. Liberation size is the major factor in determining metallurgical performance. Complex mineralogy requires a fine grind to achieve effective liberation. Fine grinding results in offsetting decreases in concentrate grade through entrainment. The economic treatment of complex fine-grained deposits requires optimisation of regrind size for liberation without unduly compromising concentrate grade through gangue entrainment.INTRODUCTIONUntil recently Teck Cominco Metals Ltd. operated three mines treating zinc-lead ore. In order of increasing mineralogical complexity they are: the Polaris Mine on Little Cornwallis Island in Nunavut in the eastern Arctic, the Sullivan Mine in southeastern British Columbia and the Red Dog Mine in northwestern Alaska. Both the Polaris and Sullivan Mines have recently ceased to operate due to depletion of ore reserves.The ore type and associated gangue, mineralogy and iron solid solution vary significantly between these deposits. Table 1 summarizes some of the important differences"

Jan 1, 2003

By Richard C. Banting

Excessive vibration is known to have an adverse affect on soft body tissue and operators of heavy mining equipment can be exposed to vibration that exceeds levels recommended in international guidelines (ISO 2631-1, for example). Research has found that many of the seat and suspension systems currently used in mine haul trucks and load haul dump vehicles are actually amplifying the vibration. This overview presentation will outline the current research being conducted at Laurentian University and the University of Western Ontario, and the roles of partners in rating the ability of a number of commonly used mine vehicle seats to isolate harmful vibration.

Oct 1, 2010

By Dayang Datu Khalil, Charle Amoah, Fred Kock

Abosso Goldfields Limited has been optimizing the comminution circuit at the Damang Mine Operation for the treatment of 100% primary ore. The optimization process started at a base rate of 343 tph when treating primary crushed primary ore, and was increased to above 600 tph with partially crushed primary ore. Abosso Goldfields engaged Orway Mineral Consultants (OMC) to assist with the optimization process in 2009 and the two companies have been working together since, to further refine the process. Continuous improvement was achieved through crushing circuit modifications, changes in operating processes and grinding control system utilization. This paper discusses the improvements developed for the increase in milling capacity and improvements in final product size.

Jan 1, 2012

By A. Azad

SAGD (Steam Assisted Gravity Drainage) is an in-situ oil recovery technique for heavy oil reservoirs. The technique has been successfully applied to many projects in the past 25 years and the process has been, now, well understood. It is now believed that geomechanics plays an important role in SAGD and should be considered in numerical or analytical modeling. Currently, geomechanics is numerically modeled through combining a multi-phase flow and a geomechanical simulator. Numerical modeling is, however, time consuming, need lots of input data, and could not be used for quick decision-making purposes. To decrease the modeling time, this study based on a new version of the Reis drainage model, proposes coupled mathematical model and reserves the effect of geomechanics in the process. Results showed a perfect match with the past experimental and numerical data.

May 1, 2009

Material scheduling, sequencing planning and execution are the core tactical mine plan for achieving production targets that maximize the objective function of any mine production entity. This objective function is constrained by several exogenous and endogenous constraints including geological, operating, technological, marketing, financial, political, social and local field constraints. Linear and dynamic programming techniques have been used to formulate algorithms to solve the problems associated with scheduling and sequencing operations. These algorithms possess the mathematical rigor for dealing with the fundamental problems but they fail to provide adequate answers to random and dynamic process problems. Materials scheduling and sequencing are carried out within the bounds of random and dynamic fields. The functional relations between the output and dependent variables are random, and thus, current algorithms are limited in their abilities to address the problems arising from these random field processes. In this study a production simulator is developed to capture the random field process associated with materials scheduling and sequencing in an open pit environment. The algorithm incorporates a geometric pit evolution model, using solid geometry of an ellipsoidal frustum to capture material displacement dynamics. Taylor series expansion about the dimensions of the initial frustum is used to provide numerical solutions to the resulting partial differential equations governing the pushback dynamics. A production simulator, derived from the stochastic and dynamic models, is developed, validated and used to simulate the changes in the pit volume resulting from periodic incremental pushbacks and the random field process. The hybrid stochastic-optimization algorithm provides a powerful tool for addressing the random field and dynamic process problems. Combined with a hybrid stochastic-optimization dispatch system, tactical production planning and execution will be efficient and economic for achieving desired.

May 1, 2004

By Matthew P. Wickham

The use of existing mine records in conjunction with an appropriate classification scheme can be used successfully to identify and characterize the composition of existing waste rock facilities where traditional approaches based on sampling may be impractical or costly. This paper describes an alternative approach used in an acid rock drainage investigation at a porphyry copper mine with numerous waste rock dumps of varying ages and composition. The approach integrated detailed lithologic and mineralogic information about the ore body and overburden materials with records of pit development and dispatch. A waste rock characterization matrix was developed for the site to meaningfully classify lithology and mineralogic composition of the waste rock. The approach resulted in a focused geochemical testing program and facilitated interpretation and application of the test results.

May 1, 2002

By V. Coffin, T. Cienski

"(Figure 1) Reagentized pulp enters into the column at about 1/4 of the distance from the top. Inside the column it meets with a downward flowing stream of water and with an upward flowing mass of air bubbles. Flotation takes place in this counter current system while at the same time fine gangue particles are washed off the froth before it reaches the overflow lip at the top of the column. The main operating features of the column flotation are as follows:a) No moving parts. Solids are kept in suspention not by an agitating action of a propeller but by settling down against the rising air bubbles.b) Wash water. Spray pipes are installed a few inches below the froth surface and deliver required volume of water. The purpose of this water is twofold:(i) it keeps in balance the flow of material through the column and(ii) it washes rising froth in the froth layer as well as removes unwanted fines attached to the bubbles at the lower flotation section. As a result the concentrate produced is of higher purity than in the conventional flotation. Column is characterized by very high up-grading. However, even temporary disruption of wash water supply results in a drastic drop of concentrate grate.c) Flow balance. (Figure 2) For the correct operation volume of the underflow (tail) is larger than that of the feed. The difference is made up by the wash water. This difference called bias is predetermined and ranges from some 4 to 15 USGPM depending on the size of the unit and process requirements."

Jan 1, 1981

By Karla Kaboth, Brad Garraway

"The surface of many concentrate thickeners has traditionally looked like that of a flotation cell. Over the last three years Normandy Golden Grove Concentrator, in partnership with Outokumpu Technology have developed and implemented an innovative breakthrough deaeration technology to address this problem.When installed in the thickener feedline, the system successfully detached air bubbles adhering to the solid particles and removed air bubbles from the feed stream, subsequently presenting a fully deaerated feed to the thickener feedwell.Tests to date have shown an 80% reduction in overflow solids. As a result, costs associated with concentrate loss and measures to recover concentrate that settles in process tanks and ponds have been minimized.MOTIVATIONIt is recognised in mineral processing operations that the entrainment of finely divided air in thickener feeds can cause significant problems in the operation of a thickener. This is particularly the case with thickening of flotation concentrates, in which air bubbles are strongly attached to the mineral particles and are difficult to remove. Such particles attached to fine air bubbles rise to the thickener surface, and hence over the weir and into the thickener overflow. High solids carryover can lead to a direct loss of mineral product, and if the product settles in process water tanks and ponds, the recovery of this product by means of intermittent dredging operations is usually expensive and inconvenient.Many concentrate thickeners are fitted with devices which attempt to alleviate this problem. Froth rings or baffles, skimmers and froth sprays, all play a part in reducing the amount of solids carried over into the overflow. However, many froths are very stable and persist despite these measures. In the worst cases, a thick froth layer forms which builds up to a depth greater than the froth ring, and hence may overflow or pass beneath the ring . Any concentrate that finds its way past the froth ring can also cause blockage of the overflow weir and launder, and has the potential to upset clarification performance by cutting off sections of the overflow handling system. The formation of a froth layer on the thickener also makes it more difficult for the operator to monitor the clarification performance."

Jan 1, 2001

By C. S. Maggs, L. Shwydiuk, H. W. Newcomen

The southwest wall of the Lornex Pit at the Highland Valley Copper mine has been experiencing slope displacements since 1978. Measures to manage the displacements on previous pushbacks have included stepping out, scheduling pushbacks to unload the crest of unstable areas, slope dewatering and mining with intensive slope monitoring. The final pushback on this wall is currently being mined and substantial modifications to the slope geometry could prove to be uneconomical. As a result, a campaign of surface water collection and diversion, horizontal drainhole drilling and deep well drilling is currently underway to maintain an acceptable degree of stability to the end of mine life. The various factors contributing to instability, including engineering geologic controls, rock mass strength, and surface and groundwater hydrology are presented. Movement trends, displacement magnitudes and stability analyses results are also discussed.

Jan 1, 2003

By J. A. Vallejos

Re-entry protocols are a tactical approach for controlling risk after blasts or large events in seismically active mines. Based on the results of a survey on 18 seismically active mines, mostly in Ontario, current re-entry practices are summarized. Over half of the mines in Ontario use event decay rate analysis as their primary re-entry decision making parameter. We study in detail the applicability of the Omori?s law as an equation for describing the event decay rate for more than 250 mining-induced aftershock sequences in seven different environments. Practical guidelines for the use of the Omori equation as a re-entry criterion are proposed.

May 1, 2009

By Masayuki Ishikawa

In a radio frequency and optoelectoronic device packaging, Gold-Tin (Au-20 wt% Sn eutectic) solder is used widely due to the excellent electrical and thermal conductivity, high strength, and negligible creep characteristic under repetitive thermal cycling. With the recent lead-free movement, Gold-Tin solder is recognized as an alternative material for high temperature Lead-Tin solder. Generally, Gold-Tin solder is supplied in the forms such as ribbons, pellets, and ring frames. However, these forms must be set-up accurately on the joint area to press chips in bonding, therefore, it is difficult for these forms to satisfy the recent requirements for the down sizing in the connection areas. On the other hand, Au-20 wt% Sn solder paste can be applied flexibly to various supplying methods, such as printing, dispensing system and pin transcript. These methods also make it possible to reduce the production cost. However, in the case of using the solder paste, the void issue is one of the most undesirable problems. The void causes the degradation of the characteristics such as the bond strength, electrical characteristic and thermal conductivity. We have been intensifying the development of the void free paste, and have achieved void reduction by optimizing the powder size, the flux composition and the reflow condition.

Oct 1, 2003