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By R. D. Brown

In view of the many changes which have taken place since 1950 in the rules of the Income Tax Act concerning the deduction of exploration and development expenses, many corporate taxpayers each year face the tedious task of determining which particular rules their unclaimed exploration and development expenses are subject to and in what sequence these expenses are to be claimed. Recent amendments to the Act have cleared up some of the mystery of the "ordering" of these deductions. This article examines the sequence in which various categories of exploration and development expenses are to be deducted in accordance with the terms of the Act as amended by Bill C-11.

Jan 1, 1978

By Norman A. M Macleod

FOR the past seven years, all flotation at the Britannia mill has been done in Forrester Air-Lift cells. Prior to 1931, the roughing and part of the cleaning operation had been performed in four 21-cell and two 14-cell M.S. machines. The resulting economies in reagent, power, maintenance, and general operating costs, and the increased recovery, more than justified the exclusive use of the Forrester machine. About three years ago, the possibility of still further improving the efficiency of the flotation section was the subject of considerable discussion and experiment. Arising from these experiments, tests were made of the practicability of using a cell of greater depth than that of any pneumatic or mechanically-agitated machine in common use. Cells were constructed with depths of 7 .5 feet, 10 feet, and 15 feet, and, in all cases, a very definite improvement in operation was indicated. The cell now being used in the mill treats from 5,500 to 6,200 tons of dry feed per day. It is 100 ft. long by 5 ft. wide by 8 ft. deep, and has replaced a total length of over 500 feet of standard Forrester machine. The choice of a depth of 8 feet was governed by the type of blower which was available-in this case, a Roots-Connersville blower, driven by a synchronous motor and delivering 6,000 c.f.m. of free air at 4.0 pounds per square inch. At the Chelan Division of the Howe Sound Company, where a new mill was recently built, all flotation is carried on in cells 10 feet deep, with good results.

Jan 1, 1938

By T. G. Paradis, C. A. Mohns

"This paper summarizes the Wren CAT (Clarifier and Accelerated Thickener) deep bed thickener operation at the EKATITM Diamond Mine in Canada’s Northwest Territories. EKATITMs’ thickener project is presented in terms of initial design considerations and present day operating practices. A circuit description summarizes process equipment, reagent systems, and typical process conditions, and details of Wren CAT operating principles are provided. Operating strategies are discussed, with emphasis on process instrumentation and control and operating challenges.INTRODUCTIONThe EKATITM diamond mine, operated by BHP Diamonds, Inc., is located in the Northwest Territories near Lac De Gras, approximately 300 km NNE of Yellowknife, NT. 9000 dry metric tonnes of diamond-bearing kimberlite ore are processed daily. Processing operations commenced in October, 1998.The EKATITM process plant flowsheet features typical steps in diamond recovery plant design. Figure 1 shows the general plant flowsheet. Size reduction and feed preparation are accomplished by crushing, scrubbing, and high pressure grinding rolls (HPGR) through closed-circuit classification with vibratory screens. Heavy medium separation (HMS) is used as the initial stage of heavy mineral concentration. Secondary concentration is accomplished in the recovery plant by attrition milling; wet, high-intensity magnetic separation (both wet and dry); and X-ray sorting.The present budget throughput rate is 9000 dry tonnes per day. This will be increased to 18,000 tonnes during the first ten years of operation. Unlike most kimberlite treatment facilities, which process material from a single ore body, EKATITM’s process plant was designed to accommodate ore from five different kimberlite pipes, each with its own treatment characteristics.All processing, except for primary crushing, is carried out in a temperature-controlled environment in the main process plant building."

Jan 1, 2000

By Judith S. Chan

With the increasing awareness of the need for the reduction of carbon emissions globally, geothermal energy, which offers a potential for cleaner energy generation, is one potential new source. In Alberta, these geothermal resources are likely to be found in the sedimentary basin, or in the deeper crystalline basement rocks. Alberta exhibits a very low geothermal gradient compared to other existing geothermal fields located in areas of volcanic and tectonic activity. To mitigate this effect, the focus in Alberta will involve the development of engineered geothermal systems (EGS) in the target resource. The first goal for EGS research and development is to develop a detailed geological-geophysical characterization of selected sites to delineate potential geothermal reservoirs in Northern Alberta. One of the selected sites is in the Fort McMurray area. The deepest well drilled in the oilsands areas of Northern Alberta is located just west of Fort McMurray. It has a depth of 2363 m and as such can provide details on the physical properties of the rocks, the state of stress, and the existence of fracture porosity toward geothermal investigations. To date, we have acquired temperature logs to study the change in geothermal gradient with depth, and a series of petrophysical logs to study the finer scale structure of the rock formations with vertical resolutions in the range of 0.05 cm to 80 cm. Our aim is to identify geological features such as zones of fractures in the basin and/or basement that could provide an indication of enhanced fluid flow potential ? a necessary component for any geothermal systems to be viable. Zero offset and walkaway vertical seismic profiles (VSP) were also conducted to measure the seismic responses at the borehole. VSP data can be used to delineate the structural and stratigraphic features surrounding the borehole that could not be resolved from surface seismic reflection data that are also available near the borehole. The full integration of well logs, VSP data and surface seismic reflection data are expected to provide a detailed characterization of the sedimentary basin and crystalline basement rocks of the Canadian Shield in Northeastern Alberta and will assist in future planning for drilling.

Jun 1, 2012

By J. J. Hussey

"Abstract-The ""Brunswick Horizon"" an informally named ore-bearing unit near the top of the Nepisiguit Falls Formation in the Ordovician Tetagouche Group, hosts the Brunswick No. 6 and No. 12 base-metal mines, as well as the former Austin Brook iron mine, in northern New Brunswick. Detailed structural analysis of the No. 6 and No.12 mines led to the prediction that a massive­ sulfide deposit may have been repeated by F1 folding along the Brunswick Horizon. A subsequent drilling program discovered the new massive-sulfide North End Zone at a vertical depth of 1100 m, 1 km north of the No. 12 underground workings. By the end of 1990, Zn-Pb-rich massive sulfides had been delineated over a strike length of 200 m and a down-dip extent of 170 m. Rock units intersected in the North End Zone are generally thinner and vary somewhat from those at the Brunswick No. 12 mine. Thinning of the hanging wall rocks may be primary, may result from attenuation along F2 folds, or may represent truncation by a thrust fault. The newly discovered sulfide zone indicates that significant potential exists for the discovery of other deposits at previously unexplored depths.SOMMAIRE-Dans le nord-est du Nouveau-Brunswick ""l'horizon Brunswick"" est le nom usuel de la zone qui contient les mines de métaux de base Brunswick No. 6 et No. 12, ainsi que l'ancienne mine de fer Austin Brook, toutes situées sur le dessus de la Formation ""Nepisiguit Falls"" dans le Groupe Tetagouche d'âge Ordovicien. Une analyse détaillée de la structure des mines No. 6 et No. 12 à permis a van Staal de prédire qu'un gîte de sulfures massifs pourrait se répéter dû à une déformation F1, au nord de Brunswick No. 12. Suite à un programme de forage, la nouvelle zone de sulfures massifs appelée le ""North End Zone"", profonde de 1100 rn, et à une distance d'un km au nord des chantiers souterrains, fut découverte vers la fin de l'année 1990, les sulfures massifs riches en Zn-Pb ont été délimités sur une longueur de 200 rn et une hauteur de 170 rn le long du pendage. Les unités de roches intersectées dans le ""North End Zone"" sont généralement plus minces et sont quelque peu différentes de celles de la mine Brunswick No. 12. L'amin­ cissement des roches pourrait être primaire ou être le résultat de l'atténuation le long des plis F2, ou soit tronqué par une faille. La nouvelle découverte d'une zone de sulfures indique un potentiel énorme pour la découverte d'autres g ""tes à ces profondeurs inexplorées."

Jan 1, 1992

By D. M. Morrison

"The most important factor in Canadian mining is not the operating cost of current projects but the availability of capital for future projects. The future of mining at depth will be producing ore from the top of the orebody working downward with very effective, tightly controlled mining methods, i.e. either selective mining or bulk mining with well controlled dilution and fragmentation. The key characteristics of future mines will be smaller access excavations, more effective ground support, very precise blasting techniques and more efficient and reliable materials handling systems. Equipment will be smaller and designed for high efficiency and low maintenance, reducing both the capital and operating cost. This means there will be fewer scoops, more continuous mucking machines and conveyor belts, both lateral and vertical.Orepass failures have become accepted and the resultant redevelopment and retramming has become common. The capital investment in so-called permanent ore passes and crusher stations becomes questionable, particularly when crushers are only necessary for less than 10% of the ore going through the system. The best way to solve the chronic instability of ore passes is, as with all of the stability problems at depth, by reducing the excavation size rather than increasing ground support. Smaller access drifts would reduce the capital cost and increase the rate of development as well as reduce the amount of waste to be handled, reducing the ground support and the ventilation requirements. Large drifts and ore passes are essential only for the equipment needed to handle large pieces of ore and the productivity of scoops is very expensive when the requirements for ventilation and large access drifts are taken into account. The key issue is the fragmentation generated by primary blasting.The future of mining in Canada will depend on simple and robust technology geared to the environment in which it will have to operate. Its survival will depend on some-thing much more fundamental and difficult to accomplish than a technological advance — it will require a dramatic change in the way the mining process is managed, how work is organized, how effort is rewarded and how costs are measured — a complete change in mind-set."

Jan 1, 1996

By The Staff

"IntroductionThe difficulties to be overcome in shaft sinking and development at depth are centred at McIntyre in and around No. 12 shaft. Generally they have been due to increasing pressures and temperatures and to changes in geological structure. This paper describes the difficulties and the measures taken to meet them.No. 12 ShaftEarly in 1932 McIntyre decided to sink an internal shaft from the deepest level, the 3875, to explore and develop known veins extending below that horizon. The location selected was a point 1,500 feet south and 1,000 feet east of No. 11 shaft, the main operating shaft through which the men, ore, and most of the materials are handled Shaft and auxiliary equipment we1e laid out for 3,000 feet, that is to 7,000 feet below the surface. The shaft was to be capable of handling 1,500 tons of ore daily from the lowest level, and was to provide ventilation, compressed air, water, and electric power to service all levels.No. 12 is an internal, vertical shaft extending from the 3875 to the 6825 level and bottoming at 7,007 feet. It is a rectangular, four-compartment shaft, 21 ft. 9¾, in. by 6 ft. 3¾ in. outside the timber (Figure 1).There are two hoisting compartments and one airway compartment, each 4 ft. 10¾ in. by 5 ft. ¾ in. inside dimensions, and a combined manway, pipe, and cable compartment 4 ft. ¼ in. by 5 ft. ¾ in. Levels have been established at 150-foot intervals, pump stations and sumps at 1,000-foot intervals, and. there are two loading pockets, one at the 5525 and the other at the 6900 level.The shaft was sunk in two stages. The first stage, consisting of preparation above the 3875 level and sinking to 5585 feet, was completed by March 31st, 1935. The second stage of deepening the shaft from 5,585 to 7,007 feet was started August lst, 1946, and completed three years later."

Jan 1, 1950

SOME months ago a Committee on Deep-level Mining was appointed [by the Government of the Union of South Africa] to consider the possibility of gold mining being carried on at a depth below 8,500 feet. The Committee consisted of Sir Robert Kotze (Chairman) , Mr. H. S. H. Donald (Government Mining Engineer), and Mr. H. R. Hill. The Committee has now made a report which was tabled in the House of Assembly on March 1st. The Committee reported that the tonnage of ore locked up in the deep level areas of the Central Witwatersrand is enormous, and in the 30 miles between Roodepoort and the East Rand Proprietory Mines has a value of about £200,000,000. The Committee says that, with good ventilation, the present system of wet mining, possibly with some modification and with the aid of refrigeration, may be carried to 10,000 feet, but that greater depths will require the adoption of dry mining. "A vigorous campaign of practical experiment into the possibility of dry mining should be initiated, and the Committee recommends to the Government the appointment of a committee of experts, consisting of representatives of the mining industry, the Mines Department, and the medical profession, with the Government Mining Engineer as chairman. The Committee suggests the provision of £30,000 for the first year for the investigations and experiments contemplated, which could best be carried out by an organization which might be styled 'The Rand Mining Research Institute' and constituted somewhat on the Jines of the South African Institute for Medical Research" . The Committee suggests that this committee of experts should arrange for experiments to be made with dry mining in one of the deepest mines, and investigate ventilation, refrigeration, support of workings, and the physiological problems connected with mining. "We emphasize the necessity of treating this whole question as one of importance and urgency. The investigations should be prosecuted with the utmost vigour and should not be delayed at any time for want of funds or for any other reason. If they are not done thoroughly and quickly, the whole scheme might just as well be left severely alone.

Jan 1, 1945

By George S. Martin, Michael D. Winship

"Placer Dome Inc. is the operator of the Musselwhite project located 100km north of Pickle Lake, Ontario. J.S. Redpath Limited was contracted to conduct an underground exploration program using shaft access.During the winter of1988, the shaft collar was established in 16 metres of water bearing sand and till overburden. This paper will illustrates the engineering techniques used to overcome the obstacles to installing a shaft collar in deep overburden. Specialized dewatering and piling procedures were employed.INTRODUCTIONHarold and Allan Musselwhite discovered gold in the Opapimiskan Lake area, north of Pickle Lake, in 1962. The prospectors were grubstaked by ten companies in 1973.A diamond drill program was initiated shortly thereafter.In 1983an underground ramp exploration program was carried out on the West Anticline portion of the property. The program was unsuccessful in establishing an ore reserve so surface exploration continued. In 1986the ""T"" zone was discovered. Further surface drilling was done and an over-all drill-indicated reserve of 6 million tonnes at 7 grams per tonne was outlined. The gold mineralization occurs in several vertical tabular deposits within the iron formation. In late 1987the joint venture partnership, now consisting of Placer Dome Inc., Inco Gold Co., Corona Corporation and Esso Minerals Canada, contracted J.S. Redpath Limited to conduct an underground exploration program on the ""T"" Zone.The scope of work for the project was to: 1. establish a 45 km winter road in 1988 and 1989;"

Jan 1, 1989

By E. S. Moore

DEEP oxidation and-secondary enrichment of ore deposits, although so important in many parts of the world, are comparatively rare in the Canadian shield. Intensive glaciation during the Pleistocene epoch accounts for their rarity. Glaciation has cost Canada much in the destruction of not only enriched ore deposits, but placers that must have been developed near our numerous gold deposits during the long period of weathering that pre-ceded the Pleistocene. There seems to be a very common misconception regarding the average depth of rock that has been removed from the shield by glaciers. These bodies of ice are usually given credit for the removal of the greater portion of the thousands of feet of rock that we know has been eroded from this large area since Precambrian time. As a matter of fact, the average thickness of solid rock removed can be measured in tens rather than even hundreds of feet, although very deep erosion has resulted in some sections where the glacial ice has been constricted in depressions, such as deep valleys and lake basins. On the other hand, there are few areas within the shield where the glaciers have not disturbed practically all of the mantle rock and some feet of the underlying bed-rock. The chances of finding deeply oxidized cappings and enriched ore deposits are therefore comparatively few and these have been found chiefly where favourable structural and topographic conditions for their formation and preservation have existed. Faulting has been responsible for several of these deposits, and easily decomposed rocks, such as. sulphides and carbonates, have been very important factors. Topographic features, such as high and resistant hills, favourably situated with respect to the ore deposits have, in a few cases, played a part in providing protection from glacial erosion and in furnishing head for the descent of surface waters. At least four cases of oxidation to depths quite abnormal in the Canadian shield have so far been found in Ontario. These are the Helen and Josephine iron mines in the Michipicoten district, the Keeley silver mine in South Lor-rain, and the Ross gold mine in Hislop township, Cochrane district. A deeply oxidized zinc deposit of unusual interest occurs in the Precambrian rocks in New York State, not far from the Canadian border, and there arc the well-known iron deposits in the Lake Superior region of the United States.

Jan 1, 1938

By C. Diaz, S. W. Marcuson, K. I. Burgess

Deep roasting in fluid bed roasters is the first unit operation in Inco&apos;s "roast-reduction smelting" process for the treatment of nickel sulphide concentrates. The roaster product, a low sulphur calcine, is reduction smelted with coke in an electric furnace to yield a sulphur-deficient matte which is then converted to low (<1%) iron matte in Peirce-Smith converters. Due to the deep roasting, a minimal amount of sulphur dioxide is evolved in the smelting and converting stages. Sulphur is eliminated from the concentrate almost exclusively in the roasters in a single, continuous, strong, gas stream suitable for treatment in an acid plant. This paper discusses the commercial scale testing of deep fluid bed roasting of nickel concentrate at Inco&apos;s Thompson Smelter as part of two commercial scale campaigns on roast reduction smelting conducted in 1981-1982. Slurry feeding, practised during the second campaign, permitted excellent control of the air/concentrate ratio in the roaster and, in turn, good control of sulphur elimination (about 80% of input). Smooth autogenous operation with high oxygen efficiencies (about 95%) was promoted by operating at bed temperatures of830°C to 850°C with calcine recycle. High throughputs and the desired metallurgy were achieved. The extensive testwork conducted during the two experimental RRS campaigns demonstrated thot deep fluid bed roasting of nickel concentrate at high oxygen efficiency is a technically viable operation.

Jan 1, 1994

By Jean-Paul Drolet

"The ultimate aim of the Law of the Sea Conference, held under the auspices of the United Nations, is to ensure that all aspects of the use of the sea are covered by international law. The question facing the nations of the world can be stated as: "" Who will control and benefit from the use and the wealth of the sea?""The United Nations Conference on Law of the Sea - known as UNCLOS - which reconvened in New York during the latter part of August 1978 was the third such Conference in the UN&apos;s history. The concepts of sovereignty over the territorial sea and freedom on the high seas have remained fundamental to the international law o f the sea until our time. The legal regime based on these two concepts developed initially from state practice meant that the unilateral actions taken by one or more countries were eventually accepted and followed by others.It was not until 1958, during the first Geneva Conference on the Law of the Sea (pursued in a second Conference in 1960) that the Law of the Sea was codified and modified to a certain extent by the then independent nations of the world in the four multilateral conventions on territorial sea and contiguous zone, continental shelf, high seas, and fishing and conservation of living resources.A third Conference got under way many years later when the members of the UN met in New York at the end of 1973 for preliminary discussions . This meeting stemmed largely from the need to fill gaps in existing international legislation which did not cover the new uses of the sea. The Conference was subsequently reconvened a number of times - in Caracas (1974), in Geneva (1975) and twice in New York (1976) for what was called "" substantive negotiating sessions."" A sixth session was held in New York in 1977; a seventh, held in Geneva at the beginning of 1978, recessed and reconvened in New York at the end of August 1978. This is what is referred to, in international jargon, as the seventh session of the Third United Nations Conference on the Law o f the Sea. The following dates are the principal markers of a saga which began some twenty years ago with the purpose of regulating the use of the oceans."

Jan 1, 1981

By Bennett McLaughlin

AGNICO-EAGLE started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1,800 tonnes per day from a 2,240 metre deep shaft. Exploration success lead to the installation of a hoisting plant capable of extracting 4,500 tonnes of ore and 1,800 tonnes of waste per day from a depth of 2,210 metres. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

May 1, 2001

By B. McLaughlin

Agnico-Eagle started sinking the Penna Shaft in 1995 with a hoisting plant capable of hoisting 1800 t/d from a 2240 m deep shaft. Exploration success led to the installation of a hoisting plant capable of extracting 4500 t of ore and 1800 t of waste per day from a depth of 2210 m. The introduction of a new rope selection factor, permitting a safety factor of 4.0, represented the breakthrough required for a cost-effective project. This paper describes the process taken to introduce the new rope selection factor and its impact on the original plant.

Jan 1, 2004

By F. A. Auld

"Traditionally deep shaft sinking from the ground surface was carried out using drill and blast methods. Although large diameter blind shaft drilling has been carried out successfully on numerous occasions previously, including as early as 1852 in Germany (Auld, 1995), little attempt has been made until more recently to mechanise the shaft sinking excavation process using down-the-hole machines. This paper reviews the development of deep shaft sinking machines from the early 1970’s up to the present day. INTRODUCTION Mechanical excavation methods can significantly improve excavation performance, in order to access natural resources faster, and labour safety is increased compared to drill and blast operations. However, shaft sinking machines need to be capable of accommodating all the basic requirements for deep shaft sinking, namely: 1. Excavation and muck removal 2. Ground stability control 3. Groundwater ingress control 4. Temporary lining installation 5. Permanent lining installation and watertight sealing 6. Ventilation 7. Secondary means of egress for personnel In addition, how the machine operates in the shaft is an important factor, either slung on ropes from a surface headgear or on its own in the bottom of the shaft. An all-embracing machine which can deal with all of the above conditions is impossible but many of these requirements can be incorporated into a single machine. Deep shaft sinking also differs greatly from normal tunnel construction which employs the use of either a roadheader arm installed within a shield or a full-face tunnelling machine for excavation. Hydrostatic pressure and ground stability problems increase with depth, whereas in tunnelling the depth is normally relatively shallow and the aforementioned factors remain approximately constant along the tunnel length. DEEP SHAFT SINKING MACHINES All the shaft sinking carried out previously in the UK was by the traditional method of drill and blast. Elsewhere, in other parts of the world, attempts have been made to mechanise the process."

Jan 1, 2019

By S. Papanakli, Th. Rondoyanni, N. Sabatakakis, K. Kavoura, G. Tsiambaos

"A representative composite fault-related landslide of the Corinth Gulf graben named “Panagopoula” is reported that considered to be one of the most prone to slope instability sites along the main motorway and railway connecting Athens with the city of Patras. The presence of tectonically highly sheared and weathered geological formations, including Alpine basement (mainly flysch) contributes to the site instability, triggered/reactivated by seismic activity and heavy rainfalls. Although a series of remedial measures have been already constructed, the inclinometer readings during the last twenty years time period show a continuous very slow movement which indicates that the landslide is still ""active"". This fact has resulted to divert the axes of the new motorway and railway through twin tunnels which are under construction. INTRODUCTIONThe spatial and temporal evolution of landslides in the case of structurally complex slopes is lithologically and often structurally controlled while their type and frequency are mainly related to tectonic and lithological anisotropy (Baron et al. 2005; Hradecky et al. 2007). The triggering mechanisms mainly include: (a) excessive rainfall generating high pore pressure and (b) strong earthquakes resulting in dynamic loading conditions at the failure surface. Data such as past earthquakes or the precipitation records are useful to be gathered when a landslide model is examined since they could act as a landslide triggering mechanism. Recording of the movement through surface and inclinometer measurements as well as combination of the above information with historical records of failure could lead to a more accurate estimation of the location of the failure surface and understanding of the landslide mechanism.Slope instability in the southern segment of the Gulf of Corinth, Northern Peloponnesus, Greece, is ubiquitous and ranges from deep-seated bedrock failure to secondary earth flows in recent deposits. In this part of Greece, the periodically induced landslide events triggered by heavy rainfall, earthquake and anthropogenic activity are closely related to active fault tectonics. The Gulf of Corinth is considered as a typical example of a relatively simple asymmetric half-graben with major border faults to the south and a flexure of the northern shore. Panagopoula landslide is located along the trace of a WNW trending normal fault (dipping northwards) (Figure 1). The area is considered to be one of those most prone to slope instability along the E95 motorway and railway connecting Athens with the city of Patras."

Jan 1, 2015

By T. L. Carpenter

"The presence of excessive water in the Gibraltar East Stage 1 pit initiated studies into the ground-water conditions that might be expected in mining the Granite Lake and Pollyanna pits. Hydrologic information obtained from a pump test program in 1974 indicated that deep-well dewatering could be successfully achieved. In 1976, a deep-well dewatering system consisting of eight wells was installed on the periphery of the Pollyanna pit . it has been responsible for a significant decrease in mining costs.This paper presents a brief summary of the engineering principles involved in the design of the Gibraltar dewatering system and the problems encountered in the installation and operation of deep-well pumps. IntroductionGibraltar Mines is an open-pit copper-molybdenite mine located approximately 230 air miles north of Vancouver in the central interior of British Columbia (Fig. I). The property consists of three separate major orebodies; Gibraltar East, Granite Lake and Pollyanna (Fig. 2). Mining commenced during the summer of 1971, in the Gibraltar East Stage 1 pit. The Granite Lake Stage 1 pit was mined from mid 1974 to mid 1976. The Pollyanna Stage 1 pit is currently being mined and the Gibraltar East Stage 2 is being developed for production. This report is intended as an outline of the studies and tests leading up to and including the installation of the Pollyanna pit dewatering system, the problems encountered and the results obtained.GeneralIn the summer of 1973, mining in the Gibraltar East pit progressed below ""daylight"" on the down-hill side and ground water very quickly became a costly nuisance in the day-to-day mining operations. Mining, maintenance and blasting costs reflected these problems. Concern was also voiced about adverse effects of ground water on pit wall stability. This concern later became a reality in the Gibraltar East and Granite Lake pits. A study was initiated to investigate various methods and costs of dewatering the pit areas. The study included in-pit sumps, deep peripheral wells and a drainage gallery system located below the pits."

Jan 1, 1980

By G. A. Pinsky, Pickard M. K

"IntroductionTWO METHODS of mucking have been used in sinking C shaft, the five-compartment production shaft of the Yellowknife property of Giant Yellowknife Gold Mines, Limited:(a) Band mucking during the original sinking in 1949 and 1950 (l); and(b) Mechanical mucking with the Cryderman shaft mucker during the recent deepening in 1954.This paper briefly describes the recent deepening and compares the performance figures of the two sinking operations.PlanningProduction planning in 1952 showed that it would be advisable to deepen C shaft in 1954 to provide for three new production levels and the installation of an underground crusher. To complete the required shaft work it would be necessary for a shaft crew to deepen the shaft about 500 feet, to partly excavate three level stations and a crusher station, and to cut a station for the loading pocket. Figure 1, a vertical section of the lower part of the shaft, shows the details of the deepening programme.During the planning period, Giant had a rather small supervisory staff and at the same time was experiencing a heavy labour turnover. As it was obvious that production would suffer if the sinking crew were recruited at the mine, it was decided that the merits of contracting-the shaft sinking to an independent contractor should be investigated."

Jan 1, 1955

By Michael Sudbury

Introduction The essence of a good presentation is said to be: Outline what you are going to say Say it Summarize what you said This is perhaps especially good advice at 8.30 a.m. So here goes: This is an attempt to put numbers on three inextricably linked subjects: People and the Future Irrigation and Agriculture Mine Water and Mine Waste

May 1, 2013

By M. Grenon

"The presence, size, orientation, nature, and persistence of geological discontinuities dictate the behaviour of a rock mass. Block size, which is defined by discontinuity spacing, by the number of joint sets, and by the persistence of the discontinuities delineating potential blocks is an important indicator of the degree of fracturing of a rock mass. Consequently, block size is represented either explicitly or implicitly in all rock mass classification systems employed for analysis and design of surface and underground mining structures. Insitu block size distributions may provide a better means to describe the structural complexity of a rock mass. These are the distributions that would be derived if the in-situ rock mass was separated into its constitutive blocks, delineated by existing discontinuities, and each block measured. This paper presents the results of a field campaign at Louvicourt Mine aiming to characterize the rock mass using different methods for determining block size and block size distributions. IntroductionGeological structural data are used to provide input data for analysis and design methods for surface and underground structures. As the collection of structural data involves considerable investment of time and effort, it is sometimes overlooked, thus denying an important source of information for mine design. What is somewhat surprising, however, is that when structural data are available, they are not used to their full potential. Recent work has shown that data on block size have potential applications in different areas of rock engineering:• Blasting — Hudson (1993) has described the excavation process as the change of a preexisting natural block size distribution to the debris fragment size distribution (Fig. 1). Lizotte and Scoble (1994) have reviewed previous efforts on integrating site specific geological conditions into blast design. Grenon et al. (1997) provide a case study where in-situ block size distributions are compared to photogrammetric studies of blasted rock.• Rock mass classifications — Block size is used in the majority of rock mass classification systems either explicitly, as in the RMi classification system Palmstrøm (1995), or implicitly, such as in the NGI system, Barton et al. (1974)."

Jan 1, 1998