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By Yong Kang, Bingyuan Yan, Dandan Zheng, Xiaochuan Wang, Dengfeng Su, Dongyang Li

"According to the characteristics of rock mass and the directional cutting technology of water jet, a new idea of light shock controlled blasting with water jet slotting was put forward. Based on the fracture mechanics theory and the stress wave theory, the mechanism of damping with water jet slotting was analyzed. On the basis of the above, the evolution law of the pressure wave and displacement field during the blasting were simulated by FEM software ANSYS/LS-DYNA. The result shows that: the oriented slot plays a good role in orientation during the blasting, and makes the energy generated by gas released by the explosives gather at the tip of the oriented slot, which makes it easier for the main crack to expand along the oriented slot and indirectly reduce the stress effect on the protected object. Meanwhile, the energy of the seismic wave is reduced while transmitting through damping slot. Finally, compared with the normal blasting with damping ditch, the maximum acceleration is reduced by 15.62%, the maximum velocity is reduced by 52.99%, and the maximum displacement is reduced by 68.32%. INTRODUCTIONIn recent years, with increasing demand for energy and space, an increasing number of underground projects have been under construction. Drilling-blasting method, as a traditional main method for rock excavation, is still an indispensable means in the engineering construction. As is known, blasting vibration will cause the deformation and unstable of the existing building structures, so how to reduce the influence on the existing building structures caused by the blasting vibration has become the focus. Traditional shock absorption measures mainly include three kinds: the first one is pre-splitting blasting, the second measure is to change the parameter of explosive filling, and the last one is to excavate damping ditch between the protected object and blastholes. However, engineering practices show that: the protected rock may be damaged in the process of pre-splitting crack construction by blasting, the second measure is difficult in operating, and the third measure is troubled by large work quantity (Song Guangming, 1999; Lou Jianwu, 2004; Lou Jianwu, 2005; Li Xibing et al., 2008)."

Jan 1, 2015

By V. Itkin

"Three methods were tested for the beneficiation of aluminum scrap, generated by heavy medium separation of non-ferrous automobile scrap residue. These were: crushing in a shredder followed by screening; grinding in a ball miff followed by screening; and eddy current separation. The best results were obtained with the grinding-screening method. IntroductionThe usual method of aluminum alloy reclamation from non-ferrous automobile scrap residue consists of a two-step heavy medium separation to remove materials lighter than and heavier than aluminum. The resulting aluminum scrap still contains over 15% impurities such as stones and glass, heavy rubber, insulated copper wire , plastics and heavy metals entrapped by macerated aluminum piece s, composite fragments, etc.(2). Upon melting, these impurities create difficulties and yield a low ingot recovery-65% to 70%, hence small foundries avoid this material.There are a number of ways to improve the quality of aluminum scrap such as:(1 ) crushing of the scrap, which powders the brittle content , a major impurity component, followed by screening out of the dust(2) eddy current separation , which removes metals from the material flow, and(3) implement better methods for density separation.The eddy current separation and two variants of the comminution-screening technique were studied by Intermetco Ltd., Hamilton , Ontario."

Jan 1, 1986

By L. Vinnett, I. Panire, J. Yianatos, F. Ruiz

"The effect of operating variables on the flotation performance at steady-state has been extensively used for modelling and simulation of separation processes. However, the dynamic characterization of key variables such as gas dispersion (Sauter mean diameter of bubbles, D32, and bubble surface area flux, SB) and froth discharge rate is rather scarce. In this paper, an experimental design allowed identifying the dynamic response of the flotation process in a laboratory scale flotation cell, using a two-phase system, airwater. The installation included automatic control for the superficial gas rate, JG, and the pulp level. Gas dispersion was evaluated in terms of the Sauter mean diameter of a bubble population and the bubble surface area flux, SB = 6·JG/D32. The D32 was measured using the McGill Bubble Size Analyzer (MBSA) along with a semiautomated algorithm. In addition, the froth discharge velocity was measured in real-time using a Visiofroth system. The control variables were the superficial gas rate and the frother concentration (Teefroth). The dynamic characterization of the flotation process is useful to design algorithms that allow the direct or indirect control of metallurgical variables such as flotation rate, concentrate grade and mineral recovery.INTRODUCTIONGas dispersion indicates the way the gas entering a flotation machine is dispersed throughout the volume of the equipment (Schwarz & Alexander, 2006). The gas dispersion is typically characterized in terms of the bubble size (dB), gas holdup (eG), superficial gas rate (JG), and bubble surface area flux (SB =6·JG/dB) (Finch et al., 2000). All these variables have significant impact on the metallurgical performance of flotation machines. For example, Perez-Garibay et al. (2014) investigated the effect of the particle size, bubble size distribution, superficial gas rate and collector dosage on the flotation performance, for the separation of a sphalerite mineral. The authors observed that recovery increased with the superficial gas rate ranging from JG = 0.04 to JG = 0.08 cm/s and also a maximum recovery was obtained for bubble size close to 300 µm. Gorain et al. (1998) reported a strong correlation between the flotation rate constant and the bubble surface area flux in a zinc cleaner circuit. Both variables were directly proportional at three froth depths in the range of hF =7 - 45 cm. Dobby & Finch (1986) incorporated the effect of the superficial gas rate and the bubble size on the flotation efficiency by means of a kinetic model for the rate constants. Yianatos & Contreras (2010) developed a model to estimate the carrying capacity in large flotation cells by including the bubble surface area flux."

Jan 1, 2016

By M. DeLucia

"Over the past 15 years, technical innovations have improved the properties and performance of monolithic refractories. As these improvements have occurred, aluminum cast-house refractory selections have changed from brick to monolithic refractories supplied as either cast in place, or precast, ""Big-Block"" installations. A review of the properties of monolithic and brick refractories is presented, as well as the technical advantages of brick for highly demanding applications. Operating conditions and issues such as temperature, alloying, corundum growth and other variables are also reviewed."

Jan 1, 2004

By F. E. P. PEARSON

Sandstone quarried from an island in Lake Winnipeg is barged 130 km to a processing plant at Selkirk on the Red River. The stone is white, poorly consolidated, and consists of rounded quartz grains of high natural purity. It is an important supplier of silica in Western Canada for glass, fiberglass, foundry and other industrial uses.

Jan 1, 1984

By T. Backers

In fracture mechanics modeling the rock mass is seen as the combination of rock material and fractures, which are evident on different scales. The activation and propagation of fractures dominates the stability and performance issues as well as fluid flow potential. Once fractures have started to grow into each other and create through going separations, stability of rock engineering constructions may be violated. Further, as fracture mechanics inherently incorporated a scaling law in the form of the participating fracture length, scaling issues can be more accurately mirrored. This contribution highlights some examples of application of a fracture mechanics based code on some rock mechanics issues such as numerical laboratory experiments, borehole stability or the creation of fluid pathways due to underground constructions. The results show explicitly the creation of fractures and connection of existing ones, and hence the safety and performance issues. It has to be concluded that the basis for frequent application of fracture mechanics on specialized challenges in Geomechanics is laid, and the needs for future developments are defined.

May 1, 2009

By Scott G. Honan, Wayne F. Luinstra

"Since 1992, the concentration of gold using gravity methods has progressed to become an important part of production at Hemlo Gold's Golden Giant Mine. Currently, the gravity circuit accounts for approximately 25% of the Golden Giant Mine's Gold production. This circuit consists of a 30 inch Center-Drain Knelson Concentrator and a Shaking Table. The evolution of gravity concentration will be discussed with an emphasis on the economic justification for a gravity circuit as well as the practical aspects and metallurgical impact of operating such a circuit. It will be demonstrated that the operation of a gravity circuit has definite benefits to the operation of the Golden Giant Mill and will continue to play an important role in future gold production.1.0 IntroductionHemlo Gold Mines Inc. Golden Giant Mine is a 3000 TPD underground gold mine and milling facility located 40 km east of Marathon, Ontario. Mining is accomplished by means of sublevel longhole open stoping. The ore is processed using conventional crushing, 3-stage ball milling, conventional cyanidation and CIP processes. The mill and concentrator are described in more detail in other publications1,2.Since July of 1992, the Golden Giant Mine has been using a gravity circuit for gold recovery in the mill's grinding circuit. Despite the fact that gold recovery averages over 96% using conventional cyanidation and carbon-in-pulp processes, the gravity circuit has become an integral part of milling operations. This paper will discuss the economic justification for a gravity circuit as well as the practical and metallurgical aspects of its operation."

Jan 1, 1996

By V. S. Sastri, G. R. Doey, R. W. Revie

"Different forms of corrosion, the various corrosive environments encountered, the mining equipment subject to corrosion and the methods to control corrosion in the mining industry are briefly reviewed along with the savings that could be achieved by corrosion control. IntroductionCorrosive conditions in mines and metallurgical plants, lead to deterioration and wastage of equipment and of materials. The cost of corrosion in the mining industry can be significant, and measures to minimize corrosion must be taken to reduce this cost(l-3). Although the data in Table I are twenty years old they indicate the significance of corrosion costs in four industrialized countries. The costs of corrosion in the U.S. metallic ores sector and in the Canadian mining industry are presented in Tables 2 and 3, respectively. Significant savings in the mining industry can be achieved by using corrosion control methods. For example, corrosion in the Canadian mining industry in 1991 cost $1460 million of which $97 million was avoidable. Indirect costs of corrosion associated with plant shutdown, lowered efficiency of equipment and overdesign are additional to the direct costs cited here."

Jan 1, 1994

By K. M. Tait, M. M. McDonald

"An overview of the status of the development and application of Integrated Gasification Combined Cycle (IOCC) power generation is presented. Current projects in North America, Europe and Japan are described, together with the status of plans to apply the technology in Canada. A brief review of the technology is presented, including promising coproduction cycles and hybrid gasification fluid bed processes. The ability of the process to be modified for CO2 to be extracted for enhanced oil recovery or disposal is addressed. The environmental impact of IGCC technology is compared to those of other power generation technologies IntroductionDefinition and HistoryIntegrated Gasification Combined Cycle (IGCC) technology is a concept which has been around for about 50 years but has been generating increasing interest in the last 10 to 15 years. This paper focusses on coal as the feedstock for gasification. Other feedstocks used in gasification systems have included oil, biomass, tires and petroleum coke. IGCC technology integrates coal gasification with generation of electricity by means of a combined cycle system which fires the produced gas in the gas turbine. Figure 1 shows the basic components of an IGCC system which are the gasifier, the gas cleanup system and sulphur recovery plant, the gas turbine/generator set, the heat recovery steam generator (HRSG) and the steam turbine/generator set. The benefits of an IGCC system over a conventional Rankine Cycle pulverized coal (RCPC) fired system for the generation of electricity from coal are that the IGCC system has potential to have higher efficiency and lower emissions of NO., SO and CO2 per unit of power produced than the corresponding RCPC system."

Jan 1, 1994

By O. Bouaziz, O. Magnea, P. Cugy, E. F. Rauch

The experimental difficulty to perform Equal Channel Angular Extrusion (ECAE) of a bulk sample of hard material such as steel was overcome. The original method proposed in this paper consists in replacing the bulk sample by a stack of alternated hard metal (steel) and soft metal (aluminium) sheets. By applying this procedure to an Interstitial Free steel (IF steel), 2.7µm grain sized material was obtained after recrystallisation. Its mechanical properties (hardness, formability in shear, hardenability and faigue limit) were investigated and compared with the properties of the same IF steel with conventional grain sizes (12m and 25µm).

Jan 1, 2004

By S. Kaushik

The control room in a mineral processing plant has become increasingly complicated with complex unit operations coupled with rapidly evolving systems of sensors and control. Even with significant automation, human intervention is required to counter various scenarios that play out every day. A typical control room operator must monitor over 300 individual points of data in order to ensure the safe and efficient operation of the plant. At the same time, the experience of the workforce is decreasing as operators retire and the new generation enters the concentrators. Global competition for skilled operators continues to be strong and the opportunity to apprentice has diminished. The challenge is to provide a skill foundation for the operators so that they can be effective in the concentrator in a timely and safe manner. Progressively, the industry is turning to dynamic simulation tied into the control system. The simulator environment operates behind the control system to emulate the plant operation, reacting as the plant would when a change is made. The operator drives the process, with realistic feedback, which enables learning in a safe environment. This paper will take the reader through a green-field case study and discuss the effectiveness of integrating an operator training simulator (OTS) on the operator’s learning curve.

Jan 1, 2014

By B. Drew, K. Budna, C. Wenzl, D. Gregurek, A. Spanring

"The metallurgy of nickel and cobalt and of copper is closely interlinked when processing sulfidic Ni-Co ores and Cu-Co ores. The respective furnaces are typically lined with magnesia-chromite refractories, which are exposed to multiple and complex stresses. The selection of the processing route, furnace type and slag system will be dictated by the specific ore type available, this will determine the individual refractory wear mode. This paper evaluates the common refractory wear mechanisms, namely infiltration, spalling and chemical attack by various slag systems, as well as sulfur attack, as observed when processing primary sulfidic ores. All these wear parameters, which are discussed in this paper, lead to a severe degeneration of the brick microstructure and a decreased lining life. Therefore, a detailed investigation and understanding of the wear mechanisms through “post mortem studies” is an important prerequisite for the refractory producer. Based on such research results, combined with specific process knowledge, appropriate brick lining solutions for nickel and cobalt processing furnaces can be recommended.INTRODUCTION The metallurgical production of cobalt and nickel and of copper is closely interlinked to the mineralogy of the respective ores: cobalt is found in African Cu-Co ores as well as in Co-rich nickel ores (laterites and sulfides). Also, Co-bearing secondary raw materials contain the mentioned elements in different contents. In pyrometallurgical processing of sulfidic ores, cobalt is generally recovered as a by-product during the production of copper and nickel, whereas it is normally not recovered separately during the processing of nickel laterites but remains in the FeNi product. Besides various hydrometallurgical production routes, the pyrometallurgical processes involved comprise smelting (i.e., production of a Cu-Ni-Co-Fe matte in electric or flash furnaces), converting and refining (i.e. removal of Fe and S as well as other elements from matte by oxidation). The ongoing trend to use higher oxygen enrichment in process air enables higher intensity processes but also increases the oxidation potential in the vessel. Therefore, during smelting and especially during the oxidative treatment in converting and refining, some amounts of valuable metals are also transferred to the slag in their oxides form. A subsequent slag treatment is then applied for recovering valuable metals from the slag, namely allowing an economic material stream handling and minimizing metal losses. This is often done in a slag reduction furnace. Additionally, copper and nickel are very good collectors for precious metals and platinum group metals (PGMs) - therefore, depending on the content of these metals, an additional refining process is used to recover these valuable metals from the matte or metal phase (Elvers et al., 1997; Davenport et al., 2002; Crundwell et al., 2011)."

Jan 1, 2017

By Wei Sun, Xiangsong Meng, Xiaodong Li, Weisheng Huang, Yuehua Hu, Chonggao Cao, Haisheng Han, Wensheng Chen, Runqing Liu, Central South University

"The similar flotability of scheelite, fluorite, and calcite resulted in the difficult separation by flotation. This work revealed the effect of water glass on the flotation of scheelite by FTIR and the wettability change of the usual cleavage plane, and proved that water glass inevitably influenced the flotation of tungsten minerals to a large extend in traditional fatty acid flotation process. A new collector, benzohydroxamic acid complexes, was found to be selective for the separation of scheelite and calcium minerals with little water glass. Hence a novel flotation process was developed for the recovery of tungsten minerals in shizhuyuan mine in China. Normal temperature flotation of tungsten minerals was developed to instead of the classical “Petrov's process” for scheelite-calcite-fluorite type ores. Compared with the traditional process, the recovery was improved by 10% and the grade of scheelite concentrate was above 55%. The disappearance or decreasing of water glass contributed to improving the recovery of tungsten and fluorite and the circulation of water and reagents.INTRODUCTIONChina is rich in tungsten resources and the proved reserves accounted for 60% of the world's reserves (Cai Gaipin et al., 2009). However the wolframite has been dried up and the scheelite resource has become the main resource of the tungsten metal. Scheelite deposits were classified to scheelite-silicate type and scheelite-calcite-fluorite type based on the associated gangue minerals. Scheelite was easy to separate from the silicate minerals. Flotation separation of scheelite from calcium minerals creates difficulties because of the existence of the same cation in the minerals and similar physicochemical characteristics such as solubility, hardness, specific gravity, PZC (point of zero charge) etc.(Arnold & Warren, 1974; Yongxin & Changgen, 1983; Ozcan & Bulutcu, 1993a; Deng et al., 2015, 2016;). The conventional collectors used in the flotation of scheelite ores are generally fatty acids or fatty acid derivatives ( Yongxin & Changgen, 1983; Oliveira & Sampaio, 1988; Sivamohan, 1988; Shi et al., 2014; Bo et al., 2015). It is difficult to separate scheelite especially from calcite with these reagents because the adsorption mechanism of these collectors occurs through chemisorption of the oleate ion onto the mineral surface (Atademir et al., 1979; Changgen and Yongxin, 1983; Hiçyìlmaz et al., 1993; Hu et al., 2011). Therefore, it is almost impossible to separate them by fatty acid flotation without using any selective depressant. Although oleoyl sarcosine was used as a selective collector in the flotation of fluorite and siliceous scheelite ores (Ozcan & Bulutcu, 1993b; Ozcan et al., 1994), this selectivity is not adequate for a low-grade calcitic scheelite ore. Unfortunately, the reagents such as organic colloids (dextrine, starch), quebracho, sodium phosphates, sodium silicate solutions containing polyvalent cations (hydrosols), etc. (Yongxin and Changgen, 1983; Schubert et al., 1990; Shi et al., 2014; Bo et al., 2015) used for calcite depression also depress scheelite to a large extent."

Jan 1, 2016

By K. Woo

The increasing move to block cave mining methods (including sublevel and panel caving) to access deeper and lower grade ore deposits as near surface sources become exhausted raises questions as to the extent and magnitudes of caving-induced subsidence as it may affect strain-sensitive infrastructure on surface. Predicting these surface deformations is difficult as they tend to be discontinuous and asymmetric due to large movements around the cave controlled by geologic structures, rock mass heterogeneity and topographic effects. Of further impediment is the sparse number of case histories available, in which actual subsidence measurements are reported to provide guidance and empirical constraints for subsidence calculations. This study reports the development of an exhaustive and comprehensive database of available (i.e. public domain) subsidence data from block cave mining operations from around the world.

May 1, 2009

By Filipe Beretta

This study investigates geophysical logging capacity to predict coal quality. It was analyzed for possible correlation, some parameters determined via laboratory analysis of coal against results for the same parameter derived from wireline logs recorded by a geophysical probe. These probes detect variations in some rock physical properties, such as their natural gamma ray emissions and electrical resistivity. Results showed a strong correlation between natural gamma and ash content, establishing a linear model to estimate ash content from geophysical logging data with a low estimation error (less than 5%). Besides, results showed that there is no correlation between sulphur content or volatile matter and resistivity, neither with natural gamma of the rocks. Ash content derived from gamma ray values can be used as secondary information to evaluate coal quality during resources estimation, using methods such as soft indicator kriging. The methodology is illustrated using a case study at a coal deposit in south of Brazil.

Oct 1, 2009

By R. J. McLeod

"CONTROL STRATEGYThe Lake Dufault Division of Falconbridge Copper Limited has been concentrating a complex copper zinc ore since late 1964. An ARL X-ray on stream analyzer was installed in 1966 for process control. A Digital Equip-ment Corporation PDP8 was added in 1968 for more complete control. To improve the system the computer was exchanged for a Moded PDP-81 in 1971.The new computer is time sharing with 8K core memory and 32K disc storage. A new interface was installed to accommodate 14 X-ray streams and additional analog signals for process control. The system gave us additional capacity and flexibility to make changes in operating programs and control strategy while on line. As the computer is used for process control a modified focal language was chosen as the operating language for ease of operation. This language is more suitable for process control than for statistical work.The main components of the control system are(a) Computer(b) Interface(c) Production Control X-ray Quantometer(d) Teletype terminals(e)Reagent feeders(f) Sample SystemThe operation of the system consists in the computer selecting the various streams to be analyzed by a PCXQ Quantometer. When the flowing sample is presented to the X-ray the intensities of the various elements are read by the computer from analog to digital converter, the assays are then computed. From the tonnage and assays the computer is programmed to determine the amount of reagent added to various parts of the circuit. The computer drives the feeders via the interface for the required amount of reagent. After following a certain sequence the computer prints out the performance and control data on an ASR35 Teletype. The data is printed out approximately every seven minutes. Any des¬ired changes in the program or strategy can be made during operation via an ASR33 Teletype connected to the computer."

Jan 1, 1973

By Peter N. Calder

Long range mine planning involves developing a mining sequence that schedules the extraction of the ore and waste materials within a final pit limit. The objective is to define a sequence that best meets the defined strategic objectives. The main steps in the creation of an open pit mine plan are the final pit limit design, the design and sequencing of the mining phases, equipment selection and operating cost estimation. Flexibility is the key strategic element in developing a mine plan. Planning the extraction sequences and rates for the various mining areas is a challenging and demanding activity. It is often necessary to consider numerous alternative strategies and what if scenarios. The number of alternatives that can be studied with limited manpower and time resources is restricted. In order to investigate strategic aspects of mine planning, a system to generate workable mine plans rapidly is required. The concept of Visual Mine Planning is that the engineer can visualize the current plan, easily change a component of the plan, such as the annual cut-off grade schedule or the production rate within a particular Phase, and immediately see the effect on the mineralogical and cash flows. If the desired result is not achieved, a change is made and the effect is again immediately seen. This paper presents results of research in this area conducted at the Pontificia Universidad Católica de Chile. The work includes the examination of cut-off grade strategy, sequencing, blending, stockpiling and shovel-truck fleet requirements using simulation.

May 1, 2003

By J. E. Tupper

"This paper will discuss strategies for the introduction of computer technology in the mine environment. More specifically, it will focus on issues such as: (a) make or buy; (b) programmer less mines; and (c) support from corporate groups.The paper relates these strategies to systems for mine operations. These will be illustrated by considering the implementation of some phases of these systems at Teck Corporation.IntroductionThis presentation addresses some of the major considerations in a strategy for mine computerization and then relates these considerations to the computerization cycle and Teck Corporation.Strategy is defined as a conceptual framework or plan to accomplish a goal. For purposes of this paper, the goals can be more simply defined for operational purposes as either increasing revenue or decreasing costs.The strategy will allow us the framework for measuring tactical decisions such as computer and software acquisitions.The Mine Life CycleTo start with, let us look at the mine life cycle from a computer systems point of view:-Exploration-Property Development-Feasibility-Construction-OperationFrom a systems point of view, the exploration cycle is oriented to geophysical and geochemical computing. Property development starts with drilling and building the geological data base. The feasibility cycle includes all stages of evaluating the decision to proceed with mine development: ore reserve calculations; mine planning; and financial projections. Construction includes project management and project accounting systems. Systems required for operation are those needed by personnel at the mine site."

Jan 1, 1982

By Rene A. Morin, John K. Kebe

"As explosives become more widely used in urban and other congested areas, governmental regulations pertaining to their use are becoming more pervasive and stringent. This is forcing the blasting industry to review its entire spectrum of operations. Greater attention is now being paid not only to the design and layout of blasts, but also to the monitoring and recording of their after-effects for both legal and business reasons.Current PracticesThe major users of explosives in urban areas are quarry operators and construction companies. A characteristic of both of these industries, at least in recent years, is a relatively low margin of profit. This, coupled with the fact that their use of explosives is relatively intermittent, prevents them from having the kind of professional consulting services that blasting operations really warrant in today's regulatory environment. When such services are obtained, they tend to be directed more at the design and execution of the blast than at the recordkeeping function. The records that are kept tend to be more in the form of a summary of the consultant's design data as opposed to the kind of after-effect detail that is necessary.The more experienced consultants and operators now realize that at least as much attention must be paid to the record-keeping as to the design work. Regulatory bodies at all levels of government are insisting on the availability of such records.Unfortunately, the instrumentation in use today for taking such measurements does not lend itself to the practice of intermittent consulting. Current monitoring and recording instruments are based on so-called analog technology of the type that has traditionally been applied to the monitoring of earthquakes. They require set-up and calibration procedures which must be repeated each time the instrument is moved, or the blasting parameters are changed, as well as complex total analysis of the recorded data. This can lend to confusion and a dilution of responsibility for anything other than the design work and possibly some summary reporting."

Jan 1, 1985

By W. J. Farley

"The Sherritt Gordon mine is 100 miles north of The Pas in northern Manitoba. Copper-zinc ore was discovered on the property in 1922. Production began in 1931 and continued to June, 1932, when operations were suspended because of the low price of copper. Operations were resumed on August 1st, 1937, and have been carried on continuously from that time to the present (March 1947). The production of metals up to the end of 1945 was copper, 287,129,880 lb.; zinc concentrate (50 per cent) 104,419 tons ; gold, 79,388 oz.; silver, 2,529,974 oz.GENERALThe ore occurs in two deposits, the east and the west. Both are enclosed in gneisses that are highly metamorphosed sedimentary and volcanic derivatives. The rock beneath the deposits, and hence forming their footwall, is gneissoid quartzite; the hanging-wall rock is basic garnetiferous hornblende gneiss. Pegmatite commonly occurs along both foot- and hangingwall peripheries and as isolated blocks and fragments within the ore zone . These blocks and fragments are considered to be residuals of unreplaced host rock .The ore is relatively coarse grained and ranges from the massive to the disseminated type. The metallic sulphides composing these, named in the order of their abundance, are pyrite and pyrrhotite ( 2-1 ratio) , chalcopyrite, sphalerite (marmatite) , and minor chalmeriite; subordinate amounts of gold and silver are recovered . The insoluble content of the ore averages about 35 per cent.Another deposit known as the Bob Lake, much smaller and lower in grade but having very similar relationships, occurs about 3 ½ miles to the northeast of the main Sherritt Gordon ore masses.STRUCTUREThe Sherritt Gordon orebodies are of the replacement type, and lie within a pegmatite sill that has been intruded along a contact between quartzite and hornblende gneiss. The two main orebodies are intimately related, for the east deposit is an erosional remnant of the lower, easterly limit of an orebody once continuous with the west body. The ore lies along the southwest limb of an overturned syncline."

Jan 1, 1954