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By D. W. Euler, B. J. Clauzier

"Implementation of an effective energy management system will reduce energy costs without impacting negatively on production.The energy management system must be designed to complement the operation and be integrated with the organization. It must be reliable and easy to use but most important, it must have an accurate and timely feedback reporting system to allow the operation to take appropriate action.Falconbridge Limited was one of the first three companies to be awarded the energy monitoring demonstration program in May 1987. The program is sponsored jointly by the Ontario Ministry of Energy and Ontario Hydro.This paper describes the approach taken by Falconbridge Limited to implement the Onaping Area Energy Management System.IntroductionThe objective of the project was to implement an effective energy management system, capable of reducing energy costs without impacting negatively on production.Energy management systems must be designed to complement the operation and to be integrated with the organization. The system must be reliable and easy to use, but most importantly, it must have an accurate and timely feedback reporting system to allow the operation to take appropriate action."

Jan 1, 1990

By Henry Smith, Stu Brown

"The Williams Mine is Canada's largest gold producer, with annual production of some 500 000 ounces of gold from two million tonnes of ore. Highly mechanized and automated underground mining practices are utilized at the property in order to help achieve high levels of productivity and the most cost-effective mining possible.Planning and design parameters for the underground ore handling system at the Williams Mine are described in this paper. Particular reference is made to the considerations that were built into the system to provide maximum operating flexibility through the use of multiple orepass systems, portable low profile jaw crushers, underground conveyors and automated hoisting equipment.IntroductionThe Williams Mine is situated in the Hernlo area of northwestern Ontario, approximately 40 Ian east of the town of Marathon (Fig. I). It is operated by the Williams Operating Corporation, which is owned equally by Teck Corporation and Corona Corporation, and is one of three adjacent properties forming the HernIo gold camp.The mine commenced operation in October 1985 at a nominal production rate of 3000 tpcd. Through an ongoing capital development program, winch was completed in late 1989, the production rate at the property was increased to its current level of 6000 tpcd. This paper describes the mine planning process and the evolution of current mining strategies with particular reference to the underground ore handling system .HistoryGold mineralization was discovered in 1944 in the Hemlo area of Northern Ontario, near the north shore of Lake Superior. A year later, 11 claims were staked over the showing and subsequently patented by the late Dr. Jack Kerr Williams.Over the next 35 years, other claims were subsequently staked, explored and abandoned in the immediate area of the 11 patented claims . In 1980 a predecessor of the Corona Corporation acquired claims adjoining the Williams property to the east. Drilling on this claim group started early in 1981 and intersected the Hemlo orebody in May of that year. In December 1981, Corona Corporation entered into an option agreement with Teck Corporation to explore and develop the property.A drilling program by LAC Minerals on the II patented claims discovered the Williams orebody in March 1982. The mine started production in 1985, pouring its first official bar of gold on December 6 of that year. Corona Corporation was awarded ownership of the Williams Mine conclusively by a decision of the Supreme Court of Canada on August 11, 1989. The court's ruling ended a legal dispute with LAC Minerals over the property initiated eight years earlier."

Jan 1, 1991

By Marcel M. Djivre

The paper will outline historically the different materials used for pouring sockets and illustrate the current trend due to inherent advantages. A section will be devoted to engineering stress analysis showing the criteria necessary for the wires not to slip inside the poured socket material. The Ontario Mining Regulations pertaining to poured sockets will be reviewed with emphasis on the acceptable type of sockets depending on usage. In addition the paper will review the proper socket preparation techniques and explain the destructive testing conducted at the Materials Testing Lab essential for the certification requirements. In conclusion the paper will show the importance of the Certification Program for the safety of Miners working in Ontario, Canada and the World. The paper is also intended to inform the Mine Operators and Consultants that to-date the .Wirelock. sockets have been used safely for hoist ropes of locked coil and non-rotating construction and for the termination of balance ropes, and that further research is required on the construction of a socket approved for rotating type mine hoist ropes.

May 1, 2003

By James D. Bliss, David M. Sutphin

"On the basis of differences derived from genetic, descriptive, and grade-tonnage data, graphite deposits are classified here into three deposit types: disseminated flake, amorphous (microcrystalline), or graphite veins. Descriptive models have been constructed for each of these deposit types, and grade-tonnage models are constructed for disseminated flake and amorphous deposit types. Grade and tonnage data are used also to construct grade-tonnage models that assist in predicting the size and grade of undiscovered graphite deposits. The median tonnage and carbon grade of disseminated flake deposits are 240 000 tonnes and 9% carbon and for amorphous deposits, 130 000 tonnes and 40% carbon. The differences in grade between disseminated flake and amorphous deposit types are statistically significant, whereas the differences in amount of contained carbon are not .IntroductionIndustrial minerals, including mineral construction materials such as sand, gravel, and crushed stone, have historically exceeded metals in global production value. Today, industrial minerals are being used in new and sophisticated ways in response to the late 1980s emerging information- and service-based economies' requirements for less metal and more industrial minerals . Natural graphite is an example of one such mine ral that has been known since ancient times, and is now finding new applications. Graphite was first used as an industrial mineral in Bavaria in 1400 A.D. where it was an important component of crucibles. Traditionally, natural graphite has been used in heavy industries. New applications, such as development of carbon-magnesite bricks a decade ago and the current advancement of alumina/graphite refractories, are increasing its graphite use. Other new uses for natural graphite, such as the use of graphite powder as a thermal blanket for the continuous casting o f steel (Northern Miner, 1987) and the addition of expanded graphite to polyurethane foam where it acts as a flame retardant (Industrial Minerals, 1987), are increasing the demand for this mineral. To meet future demand for graphite and other industrial minerals, knowledge of the characteristics of the deposit types in which they are found is important. A further look at the deposit types for graphite and at construction of descriptive and grade-tonnage models is warranted .The graphite industry recognizes three basic types of graphite , distinguished primarily on the basis of grain size: crystalline flake, lump and chip, and amorphous. These naturally occurring forms of graphite are products of metamorphism and are found in schists of various types, gneisses, and marbles. Temperatures of at [east 400°C are thought to be required for graphite formation (Landis, 1971). Synthetic graphite, also known as artificial or manufactured graphite, is a man-made carbon product and offers higher purity and lower crystallinity than natural graphite. Several authors have written about graphite's unique physical and chemical properties and the uses for individual types of graphite (Krauss et 01., 1988; Graffin, 1983; and Harben and Bate s, 1984)."

Jan 1, 1990

"The Pierre Beauchemin Mine attained commercial production in January 1989, and went on to produce 23 968 ounces of gold for the year, 3% higher than forecast. Underground development was accelerated to prepare the way for the production of an estimated 40 000 ounces in 1989.IntroductionThe Pierre Beauchemin Mine is located nine miles west of the city of Rouyn-Noranda (Fig. I).As a result of the amalgamation with Sullivan Mines in October 1987, the mine is now entirely owned by Cambior Inc.The Eldrich deposit was discovered in 1953and began production in 1955, closing in 1962 following the decrease in gold prices and the simultaneous decrease in silica content in the ore, which was sold to the Noranda smelter for flux. A total of 717 000 tons grading 0.14 oz Au/t were produced during this period.From July 1984 to October 1987, an underground exploration program was carried out by Sullivan on the Eldrich mining concession and the nearby Flavel property. The first phase of the program included reinstallation of surface facilities and dewatering of the Eldrich Mine. Following the completion of the first phase, extensive exploration was carried out, including a major program of diamond drilling. It was then decided to deepen the shaft to a depth of 1800 ft to access a new zone called the No.5 Zone .Following the amalgamation with Sullivan in October 1987, Cambior assumed the role of operator for the project, and continued the shaft deepening work that had already been started. A feasibility study was completed in April 1988 and the Cambior board of directors approved a production decision for the Eldrich-Flavel project.The preproduction program extended from May to December 1988 and was aimed at preparing the stopes in the upper part of the mine and at developing the mine infrastructure at the bottom of the mine.The mine was officially opened in August 1988. Cambior renamed the project the Pierre Beauchemin Mine in recognition of Pierre Beauchemin's pioneer-work."

Jan 1, 1990

By R. E. Lawless

The transportation challenge began with the need to move millions of tons of coal annually from Western Canada to Ontario. The paper will discuss the options which were available, the final mode selected and the economic trade-offs which were involved. It will outline the demands of unit train technology and the effect of transportation requirements on the other elements of the whole system.

Jan 1, 1979

By Robert W. Plummer

"This paper describes the use of Geographic Information Systems (GIS) as a tool for mineral exploration by using the Eskay Creek area of northern British Columbia as an example. Data entry, analysis and output are discussed. Examples of some of the capabilities of the technology are presented.The main benefit of the technology is being able to perform complex and sophisticated searches of large and diverse data sets to highlight exploration targets. A GIS is a powerful data management tool that can be used in mineral exploration. It is a computer based system that is designed for the collection, storage and analysis of objects and phenomena where geographic location is an important characteristic. The main function of the GIS is to produce information for the geologist from a variety of sources (geology, geophysics, geochemistry, mineral deposits and so forth) quickly and efficiently. This allows the geologist to examine large amounts of data in a fraction of the time than can be done using conventional manual methods."

Jan 1, 1992

By A. P. Annan, C. Vaughan, J. L. Davis

"The increase in the price of gold in the last decade has led to a significant increase in placer gold exploration around the world. Placer deposits occur in depressions along ancient river and stream channels. In many instances these channels have been covered with materials from subsequent erosion or glacial activity. Use of high resolution geophysical techniques to map the bedrock and soil strata can improve the probability of finding the placer deposits. The buried bedrock surface is often the factor controlling deposition. Ground probing radar (GPR) and seismic sounding are complementary high resolution techniques which can be used to map bedrock topography and soil stratigraphy. Current radar instrumentation operates best in coarse grained soils. Penetration depths of up to 30 m have been attained, and stratigraphic horizons have been mapped with spatial resolutions of better than 0.5 m. Although its spatial resolution is considerably lower than radar, seismic refraction achieves superior penetration in electrically conductive environments such as clay and silt soils. The seismic refraction method thus proves to be complementary to the radar method. The seismic reflection technique is analogous to the radar method. Current seismic instrumentation and energy sources however, provide limited spatial resolution and do not permit the use of seismic reflection for reflecting horizons lying at depths of less than 20 m to 30 m.This paper discusses the use of both radar and seismic methods for placer exploration. The radar and seismic techniques, the field methods, equipment, and data displays are presented. Field examples illustrate the high resolution mapping capabilities of the techniques. The radar data agree very well with the borehole data, and in fact they sometimes detect subtle soil strata variations associated with changes of permeability that were not initially observed in the borehole logging. The radar method can give a continuous profile of water table and bedrock in sandy soils. Seismic soundings are necessary to differentiate between the bedrock and water table reflections observed by the radar."

Jan 1, 1987

By Frédéric Flament, Mary Goldman, Gille Barbery

"Pilot plant testwork on autogenous and semi-autogenous grinding was conducted at the Centre des Recherches Minérales du Québec (CRM) to investigate the effect of ball addition, solids concentration in the feed, specific energy consumption and feed size distribution.A mathematical model that incorporates breakage and surface mechanisms of loss of mass was developed to predict load size distribution of autogenous and semi-autogeneous mills. An empirical model was used to predict product size distribution of autogenous and semi-autogeneous mills.IntroductionAutogenous (AG) and semi-autogenous (SAG) grinding circuits offer potential capital and operating cost savings when compared with conventional grinding. Empirical relationships have been developed to calculate specific power consumption for SAG mills using pilot plant test results (Mular et al., 1989; Barrett and Allan, 1986). Empirical models can be obtained from plant practice data but are applicable only to the particular ore and set of operating conditions used in the model. Grinding mechanisms have to be taken into account in order to develop a model that can be applied to different ores and mills.In AG and SAG, the ore itself acts as grinding media, with the finer sizes being crushed by the coarser ones. Surface mechanisms of loss of mass, in which the inner core of the particle remains intact, also take place. In SAG milling, the effect of balls also has to be taken into account. The role of each one of these mechanisms changes with particle size and the model has to account for such changes."

Jan 1, 1991

"The gravimetric dust sampler is one of the tools now available to the industrial hygienists for determining the worker 's exposure to the numerous types of particulate matter that may be present in the workplace. The paper ' reviews the different sampling trains that can be used for the two major criteria for respirable dust and some of the sources of error in this dust assessment technique.IntroductionIt may be stated simply that the measurement of airborne dust in the working environment is done for one or two reasons: namely, for engineering control purposes and! or to evaluate the potential for toxicological insult arising from the inhalation of dust particles.This paper reviews the progress made in the development of dust-assessing instruments, particularly the gravimetric types designed to meet British and U.S. dust criteria , and discusses the limitations in their use for this purpose."

Jan 1, 1981

By Steven Chung

Decision Network Modelling in a mining operation represents a complex process environment that is inherently more variable than a processing plant or factory. The uncertain availability of loading locations, haulage paths, loading and hauling equipment, along with inconsistent operator behaviour, cause a relatively large number of upset events that must be recognized, communicated and dealt with by the appropriate management authority. Traditional process maps that represent a deterministic model of the mining process can quickly break down in the face of such a volatile environment. An alternate modelling strategy, composed of decision networks, focuses on the interactions between goal-oriented entities and their environment, allowing system integrators to explicitly determine the information to be exchanged while providing feedback mechanisms that improve system flexibility and decision quality. This ensures a consistent framework for incrementally increasing system automation.

May 1, 2010

By Robert B. Parsons

"While it might seem like heresy to suggest that ""taxation"" can be a source of financing, never the less some generous tax rules can considerably enhance the tax savings pertaining to a particular expenditure or project. A basic tax knowledge, and careful tax planning, can optimize government participation in a project. INTRODUCTIONIn trying to identify sources of financing for a project, ""government"" as a source of funding is normally thought of in terms of government grants, loan guarantees, interest rate buy downs, property tax waivers, hydro subsidies, and so on. Generally, such concessions are somewhat difficult to obtain, especially in the current period of apparent fiscal restraint. One source of government funding which should not be overlooked is the income tax regime, and, at the provincial level, the various provincial mining tax regimes.While the taxpayer would not normally view a tax system as a potential source of government financing, nevertheless various federal and provincial rules applicable to the mining industry can offer attractive tax deductions - and tax savings - with respect to particular expenditures. In fact, it is not unusual for a civil servant to refer to a tax deduction as a tax ""subsidy"". For example, in the right circumstances, the cost of a smelter expansion in New Brunswick would cost the operator only 31 cents on the dollar, with the federal and provincial governments paying for the other 69 cents by foregoing tax revenues (Table I). In a sense, such tax savings could be compared to a government grant equal to 69% of project costs. Of course, not every project expenditure will generate that degree of government funding. The fact of the matter is that the percentages of tax savings attached to different expenditures cover a wide range, depending on a complex mix of factors. The point to understand is that the tax rules can offer some valuable savings, even after tax reform, and that a basic knowledge of the tax rules can yield some fruitful rewards."

Jan 1, 1989

By D. G. Champion

"A comparison of diesel engine power ratings with in-service capability, and the selection of unit size and total number of units are discussed in the paper. Engine specific fuel consumption and its evaluation in relation to manufacturers' tolerances and equipment load factors is reviewed along with the suitable plant layout. The potential for heat recovery is discussed in connection with simple and operable recovery systems f or exhaust and cooling circuits. Maintenance standards as related to improved reliability and reduced fuel and operating costs are also outlined. IntroductionDiesel generators are used in Canadian mining operations to provide electrical power for "" base- load"" requirements in some instances and for ""stand-by"" or ""emergency"" power in almost every producing mine in the country . There are over 300 mines in Canada of which only a handful have to generate their own electricity. Only one or two mine s enjoy access to a hydroelectric site. Consequently, the diesel engine is the principal prime mover because of its high efficiency relative to other prime movers in the size range in question.The author has been associated with several “base-load” plants in addition to participation in numerous projects requiring emergency diesel generators. Records indicate that engine performance in term s of reliability and efficiency lags behind other industries where the diesel engine is used more extensively, such as the shipping industry which is able to make a more prudent selection of original equipment and enjoy easy access to highly skilled operating and maintenance personnel. It is hoped that the contents of this paper will be of value to Canadian operators of diesel generators, in the generation of prime power or applications for back-up power."

Jan 1, 1986

By 13409, B. Arjang

"Ground stresses are one of the significant factors in the context of rockbursts and underground instability at some hard rock mines in Canada. Overcoring strain relief measurements using triaxial strain cells were performed at several mine sites to provide stress data for stability evaluations and mine design. Pre-mining stress determinations carried out at depths between 60 m to 1890 m resulted in the following average stress gradients:Maximum horizontal stress, s Hmax = 8.18 + 0.0422 MPa/m depthMinimum horizontal stress, s Hmin = 3.64 + 0.0276 MPa/m depthAverage horizontal stress, s Ha = 5.91 + 0.0349 MPa/m depthVertical stress, a; = 0.0266 ± 0.008 MPa/m depthThe maximum and minimum horizontal compressive stresses, with an average ratio of J.75 ± 0.45, prevail in east-west and northerly directions, respectively. Horizontal compressive stresses in excess of vertical overburden load were determined, indicating large variations in ratios to a depth of about 1000 m with decreasing trend toward depth.From present data, a particular regional zoning for the magnitude and direction of horizontal stress fields cannot be outlined.A common feature at mines with near vertical orebodies is that the maximum horizontal stress acts perpendicular to strike while the minimum horizontal stress is aligned on-strike. The vertical stress components approach the gravitational overburden load."

Jan 1, 1991

By J. Zollinger, J. R. Kennedy, E. Bouzy, B. Rouat, D. Daloz

"Ni-based superalloys have been replaced in the last low pressure stage of jet turbines for aircraft by titanium aluminides. In order to improve the properties of these Ti-Al alloys and extend their usage deeper into aircraft engines grain refinement by inoculation has been investigated. Borides are the most common inoculants for Ti-Al alloys, however they form brittle particles which are detrimental to the final properties of the alloy. Inoculants manufactured from a Ti-Al alloy with refractory metal additions were proposed to alleviate the issues arising from inoculation with brittle particles. An alloy was chosen which had less than 10% lattice mismatch with the alloy of interest (Ti-46Al) to maximize efficiency. Initial experimentation showed a decrease in as-cast grain size by a factor of 2 between the inoculated and non-inoculated samples along with an absence of the brittle particles found with boron inoculations. Investigations into the interaction between the inoculants and the melt were also carried out to better understand the inoculant size distribution and efficiency upon solidification.INTRODUCTIONTitanium aluminum alloys are an interesting material for aerospace applications. Their high temperature oxidation resistance and high specific strength make them particularly promising (Kim & Dimiduk, 1991). Recently, titanium aluminides have replaced nickel based superalloys in the last low pressure stage of the GEnx turbine engine. In order to increase their usefulness in turbines their properties must be improved for high temperature (>800oC) applications. Grain refinement is one method to improve the properties of a material, however current methods of grain refinement of Ti-Al alloys by inoculation have significant drawbacks. A new method of inoculating Ti-Al alloys by using Ti-Al alloys with small refractory metal additions (Nb, Ta) has been developed to avoid the drawbacks of current methods while still being effective grain refiners."

Jan 1, 2016

By J. C. Kurnia

Methane is recognized as one of the prime causes of underground mine disasters around the globe. A cost-effective mine ventilation system and methane control is required to ensure a safe and productive environment in an underground mine whilst keeping energy usage and operating cost at minimum. Typically methane enters a mine environment or tunnel from localized distributed sources at high initial concentration. Hence, an understanding of its dispersion from discrete sources is important to design a methane management system via effective ventilation. This study employs computational fluid dynamics to model methane dispersion in an underground tunnel which has a number of discrete sources of methane and effective ways to dilute and or disperse it. Air flow distribution within the tunnel as well as methane dispersion is simulated by solving the governing transport equations subject to appropriate boundary conditions. First, the effectiveness of ventilation duct placement is examined. Several possibilities are explored and investigated. It is found that the common configuration utilized in underground mine performs best as compared to other configurations in maintaining the concentration of methane below permissible levels. Next, a novel intermittent airflow ventilation system is proposed and evaluated via simulation with the goal of reducing the energy cost whilst maintaining methane level in the mining face below the allowable level. Parametric studies are conducted to investigate effects of various factors influencing the effectiveness and performance of this novel intermittent ventilation system. This study will provide some new ideas for designing an efficient and effective underground mine ventilation system by lowering the net average amount of air that needs to be circulated in the tunnel for a safe operation. KEYWORDS

Aug 1, 2013

By W. G. Brown

"Review of prototype testing of two types of three-phase, argon stabilized reactor/furnace indicates specialized advantages for both, as compared with existing metallurgical furnace technology. They are: the direct-arc, plasma-torch furnace (Knipp); and the indirect, plasma extended-arc reactor (PEAR), developed at the University of Toronto.IntroductionA unique type of three-phase AC, plasma extended-arc reactor, (PEAR), shown in Figure la with gravity feed, has been undergoing development at the University of Toronto, during the past fifteen years: argon gas, introduced axially through drilled-holes in ordinary graphite electrodes, increases the length of indirect arcing and improves electrical stability while decreasing electrode consumption as compared with the performance of AC electric arc furnaces (EAF 's). Meanwhile and independently, a three-phase, transferred arc plasma furnace (Fig. 1b) has been developed by the Krupp Research Institute in Germany, using argon-stabilized, water- cooled plasma-torches with thoriated tungsten electrodes.Accordingly, the two types of furnace are similar as to both three phase and stabilized operation, but otherwise they differ in several respects, ranging from indirect versus direct-arcing to principal intended application and current state of practical development. Between them they raise questions: (I) of their present or fore seeable economics in comparison with existing processes they are intended to replace , (see Heinke and Neuschutz, 1986, for a review of the merit s of AC and DC plasma-torch furnaces); and (2) of the state of development and accessibility of their plasma theory-in-common."

Jan 1, 1991

By Stéphane Chevrel

Non-energy raw materials are vital inputs for the EU?s economy and maintaining fair and undistorted access to these materials for EU industry and citizens is increasingly difficult. Within the EU, exploration and extraction have to face increased competition for different land uses and a highly regulated environment. While the EU is currently dependent on the importation of many metals, the overall potential for mining and quarrying in Europe is strong. In spite of this, the land area available for extraction in the EU is constantly decreasing, turning access to land into a key challenge for the extractive industry. The EOMINERS project aims at contributing to demonstrate how to improve the EU capacity in implementing new mining sites and their societal and environmental acceptability. The overall aim of EO-MINERS (Earth Observation for Monitoring and Observing Environmental and Societal Impacts of Mineral Resources Exploration and Exploitation) is to bring into play EO-based methods and tools to facilitate and improve interaction between the mineral extractive industry and the society in view of its sustainable development while improving its societal acceptability. EO offers a unique opportunity to collect necessary spatial parameters that play a key role for better assessments of mining-related environmental and societal impacts. It could enable the development of means to identify the site-specific environmental and societal footprints of mineral resource extraction and to determine their respective significance. This understanding of global and cumulative footprints along a causal chain is needed in order to target policy measures. In this way the expected reduction of environmental and societal footprints in the mining sector can be most effective for the environment and more cost-efficient for public authorities and commercial operators. The project first defined environmental, socio-economic, societal, and sustainable development indicators and criteria that can possibly be dealt with using EO techniques. After an analysis of policies related to the environmental and social footprint of mineral industries, project expertise and stakeholder interviews (national and on-site) as well as site investigations led to the establishment of a list of indicators to be monitored, either directly or indirectly, through accessible parameters. Development of EO-based monitoring tools is then carried out over three demonstration sites: the lignite open pit of Sokolov in Czech Republic, the Mpumalanga coalfield centred on the town of Emalahleni (previously Witbank) in South Africa, and the Makmal gold mine in Kyrgyzstan. From these developments, it is subsequently intended to contribute to the development of generic, standardised EO data integration schemes, in particular in view of characterising affected ecosystems, populations, and societies and prepare indisputable documents that will make the basis for a sound ?trialogue? between industry, governmental organisations, and stakeholders. This paper discusses results obtained after three years into the project, focusing on product development over the demonstration sites and their relevance to the observation and monitoring of environmental and societal footprints of the extractive industry.

Aug 1, 2013

By Sebastian Siebert

Unmanned Aerial Vehicles (UAV) as a data acquisition platform and as a measurement instrument have become attractive for many surveying applications in civil engineering. However, their performance is not well understood for these particular applications. The specific scope of the presented work is the performance evaluation of a UAV system that was built to rapidly acquire mobile 3D mapping data for large earthmoving construction sites. Details to the components of the developed system (hardware and control software) are explained. A novel program for photogrammetric flight planning and its execution for the generation of 3D point clouds from digital mobile images is explained. A performance model for estimating the position error was developed and tested in several realistic construction environments. Results to these tests are presented as they relate in particular to large excavation and earth moving construction sites. Results and experiences with the developed UAV system are in particular useful for researchers or practitioners in need for successfully adapting UAV technology for their application(s).

Aug 1, 2013

By F. Urekar, R. B. Pankhurst

"Air spaces and air gaps in an explosives column are known to allow greater distribution and cushioning of explosive energy from the rock mass. This energy distribution is enhanced if the explosives ' gases can be confined in the borehole for as long as possible by plugging and stemming above the air space.Power Plug is an inflatable plug which can seal a borehole at any point to separate the stemming from an air gap and explosive toe load.IntroductionThis paper will discussion-going work by C-I -L Inc. and operators of two open pit mines to study the results of using Power Plugs:I. Pit wall stability - the authors have found the Power Plug effective for wall control blasting in open pit mines.2. Selective mining of coal seams - the authors work shows the Power Plug allows mining selective coal seams by predrilling underseam waste wedges.Pit Wall StabilityWall stability in an open pit mine is essential for safety. Good wall stability can be achieved with wall control blasting techniques which cushion the effect s of the explosives charge by decoupling the charges from the borehole wall. The usual method of decoupling a charge in a large-diameter rotary borehole is to load the explosives in tubes (Fig .I) . We now believe the air deck system is effective in sea ling a borehole above the explosive charge to create an air deck within the borehole which will cushion the blast.In a linear decoupled charge, an air annulus surrounds the explosives charge and cushions the effects of detonation genera ted gases on the pit wall. In an air deck, i.e. with the hole plugged at the collar, the gases genera ted by an explosive toe load are sealed in the empty borehole column. After a period of time, these trapped gases produce radial cracking between holes along the entire length of the borehole.It is common practice to employ de coupled explosive charge columns in the borehole to limit blast damage to surrounding rock. The exact mechanism of energy transfer in such blasts, however, is not well understood. Interruption of the continuous explosive column in a borehole by means of stemming, or air decks, may also be viewed as another form of decoupled blast. Decoupling of the explosive charge from the borehole wall affects both explosive energy release and explosion pressure developed in the borehole."

Jan 1, 1988