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By Marek Mika

This Paper has been prepared to be presented at the 23rd World Mining Congress & Expo ? Montreal 2013. It presents the idea how to carry out the shaft sinking operation, going through highly water-bearing and very weak rock strata, giving as an example one specific shaft sinking project which is being executed for one of the Polish collieries by our Shaft Sinking Company Content 1. Introduction. 2. Hydrogeological conditions within the area of the shaft. 2.1. Hydrogeological conditions assumed at the stage of designing. 2.2. Hydrogeological conditions encountered in the course of sinking. 3. Designed shaft lining. 4. Procedures for the shaft sinking. 4.1. Designed procedures of the shaft sinking. 4.2. Procedures for preservation and strengthening of the shaft lining and the surrounding rock strata. 5. Technological guidelines for proceeding with the shaft sinking ? selection of special methods. 6. Options for mechanization of work for the selected method. 7. Conclusions.

Aug 1, 2013

By Matthew S. Hall

Gold/iron oxide catalysts have been prepared and their catalytic performance evaluated for low temperature CO oxidation. The method and temperature used to dry the sample has a significant effect on their catalytic activity. Analysis by TEM revealed the catalysts contained Au particles, although catalysts with high and low activity did not always differ in their microstructure as evidenced by TEM. Catalysts were characterised using XPS and the difference between the Au(4d) and C(1s) binding energies measured; in general the greater the difference, the higher the catalytic activity of the material.

Oct 1, 2003

By A. I. A. Salama, M. W. Mikhail

"The existing methods of block diagram manipulation and vanishing variable for flowsheet simplification used in coal and mineral processing circuit evaluation and optimization cannot be easily implemented on digital computer.The signal flowgraph technique is proposed to represent and simplify determination of the relationship between intermediate or end variable and the feed in the flowsheet. Typical and existing circuits are used to demonstrate the application of the proposed technique which can easily be implemented on digital computers.IntroductionRecently there has been much interest in the analysis and optimization of coal and mineral processing circuits to assist in the pre diction of coal and mineral processing plant performance. The block diagram and the vanishing variable were introduced and utilized in the analysis of plant flowsheet. Although the block diagram approach is useful, it requires manual manipulation of the circuit block diagram which may present difficulties in the situation of complex circuits. Moreover, it may not be easy to implement on a digital computer.In this paper, the signal flowgraph technique is proposed to represent the circuit flowsheet and to simplify the determination of relationships between intermediate or end variables (fractional mass) and the feed for any coal and for any mineral processing circuit comprising size and density separators. These relationships are utilized in the analysis and/or optimization of the circuit. The proposed technique is illustrated by considering typical and existing circuits."

Jan 1, 1987

By Victor Maksaev, Marcos Zentilli

"Abstract - The Domeyko Cordillera, the westernmost uplifted crustal block of the composite High Andes of northern Chile (20°S to 28°S) hosts a narrow N-S trending belt of Late Eocene-Oligocene giant porphyry copper deposits, which include Collahuasi, Chuquicamata, El Abra, La Escondida, and El Salvador. These deposits are spatially and genetically associated with the closing igneous activity along this range, prior to a 30 km eastward jump of the magmatic front in response to tectonic plate interaction. The porphyry copper deposits are also spatially associated with a major intraarc strike-slip shear system, the Domeyko Fault System. Although the tectonic uplift of the 3000 m to 5000 m high range has generally been assumed to be mostly Miocene in age, field relationships suggest that the Domeyko Fault System and tectonic uplift were active as early as the Eocene, coinciding with porphyry copper emplacement between 41 Ma and 30 Ma. Apatite fission track (FT) thermochronology provides both age data and a time-temperature history for rocks since they cooled below a temperature of ca. 125°C (equivalent to a depth of 4 km to 5 km under normal geothermal gradients) on their way to the surface during exhumation, or after a heating event. Apatite FT data from the Paleozoic crystalline basement of the Domeyko Cordillera indicate that at least 4 km to 5 km of rocks were eroded during exhumation of this tectonic block between ca. 50 Ma to 30 Ma (Middle Eocene to Early Oligocene), a time that immediately precedes and overlaps with the emplacement of giant porphyry copper deposits. The FT data constrain the age and duration of a period of crustal thickening and extensive erosion known as the Incaic compression, an event recognized in the Andes of Chile and Peru. Assuming that cooling was due to denudation alone, modelling of the FT data allow estimation of denudation rates between 200 and 100 m/My during this period. In contrast, exposures of pre-porphyry Paleocene intrusives on the western edge of the Domeyko Cordillera reveal apatite FT ages that are concordant with biotite 40Ar-39Ar dates, indicating shallow emplacement, fast cooling and negligible exhumation. The apatite FT ages of the Chuquicamata and El Abra porphyry copper deposits are only marginally younger than their 40Ar-39Ar dates, implying fast cooling/exhumation of shallow mineralizing systems (ca. 2 km to 3 km). Their FT time-temperature history is compatible with extremely low rates of exhumation (ca. 50 m/My) since about 30 Ma (Early Oligocene). This limited extent of erosion, due to exceptional aridity, has greatly contributed to the preservation of rich supergene enriched blankets above some of the porphyry copper deposits.A model is proposed, which is consistent with field relationships, geochemical, and geochronological data. High relative velocities and intermediate-angle oblique convergence between the Nazca and South American plates in the Eocene-Early Oligocene led to intra-arc transpression partitioned into reverse faults of opposing vergence and a right-lateral shear system (the Domeyko Shear System) localized along the magmatic front. Crustal shortening and thickening led to uplift within the Domeyko Fault System and to erosion of at least 4 km to 5 km. Crustal thickening deepened the zone of magma generation, and magmas accumulated in the lower crust, allowing small volumes to rise rapidly to shallow levels along transtensional domains of the regional shear system. A similar model of crustal thickening and shortening before and during porphyry copper emplacement in zones of transtension may also apply to the Miocene-Pliocene giant porphyry copper province of central Chile."

Jan 1, 1999

By S. L. Gula

"Effective and timely communication during routine operations, and especially during emergency situations, is no easy task in any underground mine. At Cominco Fertilizers, Potash Operations, where 150people are employed underground to produce 3.1 million tonnes of potash per annum at a depth of 1100 m (3600ft), this is no exception. The over-all mine workings underlie an area of approximately 20 km 2 with average travel time to the active mining areas being approximately 30 to 40 minutes by light vehicle, and significantly longer than this for heavy equipment.In a mine of this size, the deployment and management of personnel and materials on a day-to-day basis, and during mine emergencies, is an important exercise. The Personal Emergency Device (PED) system has provided the Potash Division a means to achieve improvements in this area and reduce the communications bottleneck.The MineAt Cominco Fertilizers Potash Operations, approximately 30 km southwest of Saskatoon, the orebody is the same horizon being mined by other potash producers in the Saskatoon area and extends over 300 km in an east-west direction, and approximately 150 km in a north-south direction. Mining operations are carried out with approximately 150 employees operating on a continuous-shift basis, seven days a week.Mining is presently being done from Block 6 which takes the mine to its northernmost boundary and contains reserves of approximately 50 million tonnes. Production is from one level by five twin rotor continuous mining machines, each capable of cutting a face up to 5.5 m wide and 3.3 m high . All ore is transported to the shaft via approximately 20 km of conveyor where it is removed to surface by two 24 tonne skips.After the ore is conveyed to the mill for processing, the finished product is shipped by rail car or trucks to other parts of Canada, the United States or through Vancouver to other parts of the world."

Jan 1, 1993

By Dan Currie, Tom Lamb, J. Coady Marsh, Gary Landry

"This paper describes the Cape Breton Development Corporation's experience with the Lovat M-300 tunnel-boring machine at the Donkin-Morien Mine. Between January 3 and December 21, 1984, the 7.6 m (25 It) diameter TBM advanced 3350 m (10 990 ft) . The authors will describe experiences with the machine and highlight the implications of tunnelling machines to underground coal mine development in Canada. IntroductionThe Cape Breton Development Corporation (CBDC) has recently completed the drivage of a 7.6 m (25 ft) diameter tunnel, 3.5 km (2.2 miles) in length , to access the Harbour Coal Seam at the Donkin-Morien Project. The tunnel was successfully driven with the first Canadian rock tunnel-boring machine (RTBM or TBM), designed and built by Lovat Tunnel Equipment, Inc. The initial mine development consists of the drivage of two tunnels to the first major coal seam. Future plans are proposed for the development of a 4 million tonne-per-year mine (Marsh et al., 1983, Gillman, 1982), which will require the drivage of a further two tunnels and could access up to four coal seams. The tunnel cross-sectional areas were designed to provide sufficient ventilation area and access for a production of 4 million tonnes per year."

Jan 1, 1986

By G. M. Ritcey, A. W. Ashbrook

"This paper summarizes the optimum leach conditions for each Of several cobalt-containing arsenical feed materials, describes the solution treatment prior to purification of cobalt recovery, and discusses the plant operation on one feed as well as the treatment of effluents.IntroductionDuring the period 1962-1964, when the demand for uranium was low, Eldorado Mining and Refining Limited (Eldorado Nuclear Limited) made a decision to undertake a three-year diversification program. One area chosen in this program was that concerned with the processing of cobalt-nickel materials. Many such materials were evaluated over the three-year period, ranging from tailings, residues, ores, concentrates and speiss to metal scrap. Cobalt feed materials, on which much of the effort was concentrated, were those containing arsenic together with other metals such as silver, copper, nickel and iron. This paper describes the treatment of arsenic-bearing feed materials (ranging from 0.3 to 570/0 As) and the subsequent purification stages required before the separation and recovery of high-purity cobalt. Because of the current interest in treating cobalt ores, it seemed appropriate that the information on the treatment of various cobalt feeds should now be made available . Although a large amount of data were generated during the research and process development program, a complete scientific correlation and understanding could not be achieved. Nevertheless, the data may provide a guide to others involved in processing not only cobalt, but other arsenical ores."

Jan 1, 1981

By T. R. C. Aston, C. M. K. Yuen, J. L. Gilby

"The access tunnels for the Donkin-Morien Mine in Cape Breton, Nova Scotia, comprise two parallel tunnels driven through a sedimentary sequence of sandstone, siltstone and mudstone to intersect the Harbour Coal Seam under the Atlantic Ocean, approximately 3.5 km offshore (Fig. 1). The No. 2 tunnel was driven a total distance of 3579 m using a 7.6 m diameter Loyat full-face tunnel boring machine (TBM) and was supported by steel sets. The No. 3 tunnel was initially driven a distance of 1027 m using drill and blast methods (dimensions 7.6 m wide by 5.3 m high) supported by rock bolts and shotcrete. This tunnel was then completed (front March 1986 to February 1987) using the tunnel boring machine to a distance of 3573 m.During the period May 1983 to December 1984, a major geotechnical research program was undertaken in the Donkin-Morien tunnels by Golder Associates in conjunction w,ith CANMET and the Cape Breton Development Corporation (Yuen et al., 1985). The research program included the monitoring of the performance of the TBM and drill and blast drivages, and the study of the thrusting characteristics and rock-interaction of the TBM excavation. The main emphasis of the research program was on the collection of field data which was to be made available in the form of a comprehensive report for the future use of others who might wish to carry out a detailed interpretation and analysis. The information gained from the program was also used during the tunnel"

Jan 1, 1988

By E. Mohammadi Zahrani

In this study, Mg-doped fluorapatite (Mg-FA) nanopowders were prepared through a sol-gel, technique and characterized. Designated degree of Mg2+ ions incorporation into the apatite structure was indicated by the x value in the general formula of (Ca10-xMgx (PO4)6F2), where x=0, 0.25, 0.5, 0.75, and 1. XRD, AAS, FTIR and TEM techniques were utilized to characterize the synthesized nanopowders. In vitro bioactivity of the powders was evaluated in simulated body fluid. Powders had a crystallite size less than 100 nm. It was concluded that Mg-substitution could alter bioactivity and dissolution behaviour of Mg-FA. These two parameters were proportional to magnesium content of the powders.

Jan 1, 2010

By Sukumar Bandopadhyay, Arunapuram Sundararajan

"For the last three decades, the application of network planning has provided a basis for a formal and general approach to the discipline of project management. For fixed activity duration, a very simple algorithm commonly known as critical path method (CPM), gives the length of time required for the total project as well as indicates the activities which are vital to the completion of a project. Project Evaluation Review Techniques (PER T) on the other hand, generalize the above approach to recognize uncertainty in the activity durations by allowing them to be random variables. One of the misleading aspects of current "" PER T"" solution method is, however, the implication that there is a unique critical path. In general, any number of paths could be critical, depending on the particular realization of the random activity durations that actually occur. In this case, simulation can be utilized to estimate completion time of a project.In this paper, the concept of criticality indexing is discussed, and a simulation model application which defines the critical path based on the criticality indexing concept, to a longwall development - extraction network, is presented. The model also provides suitable scheduling of resources based on the resource constraints and smooth s out period-t o-period assignments. IntroductionThe successful management of large-scale projects require careful planning, scheduling , and coordinating numerous interrelated activities. To aid in these task s, formal procedures based on the networks and network techniques (variously called PERT or CPM) were developed. In its original form the completion time for individual activities of a project was assumed fixed and known in advance: this in turn led to the familiar algorithms for computing the critical path, earliest start time, slack, and so forth. The unreality of such an assumption is, of course , apparent in many contexts. Consequently, attempts were made to introduce probalistic activity completion times, allowing representation of the stochastic nature of most projects."

Jan 1, 1987

By Lawrence Devon Smith

"The concept of risk is well established in the mining industry. It is acknowledged when estimates of reserves are expressed as proven or probable, when mining and metallurgical recoveries are applied to the ore, and when contingencies are added to costs. However, it is difficult to provide a quantitative assessment of risk. The significant sources of risk in a mineral project and how these are addressed in project evaluations are discussed.The discount rate is examined as a fundamental means of reflecting risk in discounted cash flow evaluations. Current industry practice is discussed, and a methodology for the analysis of risk levels is proposed that assesses the constituent components of the discount rate: real interest, mineral project risks, and country risk.IntroductionThis paper examines the components of the discounted cash flow discount rate and proposes a method of estimating project-specific discount rates. The motivation for this work comes from experience of project evaluations in which owners and purchasers had agreed on virtually every aspect of the evaluation except how much the project was worth. Agreement was reached on reserves, grade, recovery, capital costs, operating costs, taxes, and, by combining these components, even on the final cash flow values. The only difference in opinion concerned the discount rate to be used in the calculation of the net present value. Depending on the life of the project, such differences of opinion can cause a variation of more than 50% in the value placed on a project! This is illustrated in Figure I."

Jan 1, 1995

By R. B. Stein

"Countercurrent decantation circuits(CCD) are often employed in hydrometallurgy to effect solids-liquid separation in combination with a barren solution wash to reduce losses of valuable solution component(s) from the tails. Bechtel Corporation uses its BEMSIM flowsheet-modelling PC computer program to simulate a CCD circuit where the ""dirty"" wash solution contains significant amounts of soluble components. An algorithm successfully models this condition and is simplified to a single expression when the wash solution is a ""clean"" solution containing no solubles. The CCD calculation module is compared to operating data from uranium and nickel-cobalt CCD circuits.IntroductionHydrometallurgical process schemes have often relied on countercurrent washing methods to reduce soluble losses of valuable product in the tails. Commonly used equipment to effect this operation is a CCD circuit of N thickeners in series, where a slurry is fed to thickener I and a wash solution to thickener N; clear pregnant solution overflows thickener I and washed tails exit as underflow from thickener N. CCD circuits of this type are typically employed when the solids tend to slime heavily and where a filter is not economic.A typical CCD circuit usually employs from two to five thickeners and can employ either a ""clean"" washing solution of, say, pure water or else the hydrometallurgical circuit may generate a ""dirty"" barren solution containing an appreciable amount of soluble component which may be advantageously returned to the process as CCD wash solution. Various authors have treated the case for clean washing solutions (Svarkovsky 1977, Merritt 1970). For the case of dirty wash solutions, an algorithm has been developed to enable efficient modelling by the BEMSIM computer program, because the need for an accurate method to calculate soluble losses is required when performing an economic trade-off analysis of the value of product lost in the tails as a function of the number of thickeners."

Jan 1, 1990

By P. R. G. Brandão, E. E. Ferreira

The presence of metallic cations in solution will affect the aggregation or dispersion of the fine hematite particles, depending on the type of cation adsorption: either specific or non specific adsorption. In this work, the zeta potential measurements were carried out on a sample of pure hematite as a function of pH and metallic cations concentration (Ca2, Mg2+, Mn2+, K+, Na+ and Al3+). The objective of these studies was to clarify the effect of these metallic cations on the surface chemical properties of pure hematite. The cations K+ and Na+ adsorbed as non-specific species and caused only the reduction on the values of zeta potential (in terms of absolute value) over the entire range of pH values tested. For the Al3+ cation, in the acidic pH range it adsorbed as a specific species and increased the zeta potential values. The cations Ca2+, Mg2+ and Mn2+, adsorbed as a non specific species at pH levels less than 6.0 and caused the reduction of zeta potential due to the compression of the electrical double layer. However, for pH values greater than 6.0, these cations adsorbed as a specific species causing the zeta potential to increase and became more positive as the pH value increased (alkaline). This effect could be due to the adsorption of some hidroxy complex species of these cations, which contributed to the positive charge. The effect of metallic cations (Ca2+, Mg2+ and Al3+ concentration, at pH 4.0, 7.0 and 10, showed the following results: a) at pH 4.0, increasing the concentrations of Ca2+ and Mg2+ resulted in on a small reduction in the value of the zeta potential. At this pH, increasing the concentration of A131 cations caused the zeta potential to increase due to specific adsorption of a negatively charged Al3+ hydroxy complex b) at pH 7 and 10, increasing the concentrations of Ca2+ and Mg2+ caused the zeta potential to change its charge from negative to positive.

Jan 1, 2004

By P. E. Weidmark

"CANMET InformationPART 1-Published PapersAsmis, H. W., ""The dynamic response of caverns in discontinuous rock""; Proc 22nd U.S. Symposium on Rock Mechanics, Cambridge, Mass, June 1981, 272-277; 1981.Austin , M.W., Bray, J.W. and Crawford, A.M., ""A comparison of two indirect boundary element formulations incorporating planes of weakness"" ; Technical Note; Int J Rock Mech Min Sci Geomech Abstr; 19:339-344; 1982.Barrett, J. R., ""Applying geotechnical theory to underground metalliferous mining""; Proc 1st Intnl Conf on Stability in Underground Mining; Vancouver, BC, August 1982; SME of AIMMPE; 210-222; 1983.Barron, K., Wright, P.L. and Smales, T., ""Guideline s for the design of coal pillars in the No .4 seam at Mclntyre Mines Ltd ., Grande Cache, Alberta""; Proc 1st Intnl Conf on Stability in Underground Mining; Vancouver, BC, August 1982; SME of A IMMPE; 559-578; 1983.Bauer, A., ""Wall control blasting in open pit mines""; Mining Engng; 34:155-158; 1982.Bieniawski, Z.T., "" Improved design o f room-and-pillar coal mines for U.S. conditions""; Proc 1st Intnl Conf on Stability in Underground Mining; Vancouver, BC, August 1982; SME of AIMMPE; 19-51; 1982.Blackwell, G.H. and Calder, P.N., ""Practical aspects of wall stability at Brenda Mines Ltd., Peachland, BC""; 3rd Intnl Conf on Stability in Surface Mining; Vancouver, BC, June 1981; SME-A1ME; 3:573-608; 1982.Blake, W., ""Microseismic monitoring for underground stability "" ; Proc 1st Intnl Cont on Stability in Underground Mining; Vancouver , BC, August 1982; SME of AIMMPE; 272-294; 1983.Brawner, C.O., ""Stabilization of rock slopes"" ; 3rd Intnl Conf on Stability in Surface Mining; Vancouver, BC, June 1981; SME-AIME; 3:289-310; 1982.Bridges, M.C., ""Review of open stope mining in Australia""; Proc 1st lntnl Conf on Stability in Underground Mining; Vancouver, BC, August 1982; SME of AIMMPE; 813-828: 1983."

Jan 1, 1983

By Yi-xin Zhoa

The characteristics of coal bumps are analyzed based on the microseismic data from No.8935 workface in Xinzhouyao coal mine, Datong Mining Group. The geology of this workface is characterized by the thick sandstone roof and coal seam, both with relative higher stiffness and strength. In order to investigate the mechanism and precursors of coal bumps occurred in No.8935 workface, the locations of microseismic, the relationship of microseismic energy and frequency and the spectrum of microseismic signals are analyzed. The result shows that the coal bumps in No.8935 workface were mainly induced by the seismic caused by roof failure. The coal pillar near the goaf is more easily to bump. The statistics results indicate that the coal bumps were mainly occurred in the gate road near the pillar, less than 50m ahead of mining face and located in the hard roof adjacent with coal seam. Moreover, the frequency, energy, b-value and frequency spectrogram of microseismic events were found to decrease before coal bumps. It was found that the frequencies of the microseismic events before coal bumps mainly concentrate upon 5~60Hz. The sudden decreasing of frequency and increasing of amplitude of microseismic events can be regarded as a precursor of coal bumps.

Aug 1, 2013

By William D. Gallant, Thomas M. Barczak, Carol Tasillo

"This paper describes the results of full-scale testing of several multi-layered wood crib configurations that were tested in the Bureau of Mines mine roof simulator in cooperation with the Cape Breton Coal Research Laboratory and Cape Breton Development Corporation of Sydney, Nova Scotia. Nine different crib configurations currently being used as wood packwall supports for advancing longwall applications in Canada were evaluated. Configuration parameters understudy included the aspect ratio (height-to-width relationship) and percentage of solid material used in the crib construction. Test results and generalized wood crib behaviour are discussed in detail. Recommendations are made concerning crib constructions to maximize strength and stability. A cost benefit analysis of multi-layered wood crib configurations is made. A comparison of laboratory results and underground observations of several wood packwall supports in the Sydney coalfield suggest in situ load capacity is less than that measured in laboratory testing. Reasons for the apparent decrease of in situ load bearing capability are described.IntroductionA cooperative effort was undertaken by the U.S. Bureau of Mines with the Cape Breton Development Corporation (CBDC) and the Cape Breton Coal Research Laboratory (CBCRL) to evaluate the behaviour of gateside packing materials used in advancing longwall mining applications in the Sydney coalfield. As part of this effort, full-scale tests were conducted on wood packwall supports in the Bureau's 3-million pound (13.3 MN) active load frame.Nine different pack configurations were evaluated as part of this study. The wood packwall supports were multi-layered crib constructions from 6 in. (0.15 m) by 6 in. (0.15 m) cross section timbers using timber s 30 in. (0.75 m) and 60 in. (1.5 m) in length . The percentage of solid material in the crib constructions varied as illustrated in Figures 1 and 2. A summary of crib constructions is provided in Table 1."

Jan 1, 1991

By J. R. Maxwell

In 1970 expansion was completed increasing mill capacity from 2,000 to 3,000 T.P.D. Actual grinding capacity is 3,400 T,P,D. at a grind of 60% -200 mesh,The ore bodies are vein type, containing about 12% sulphides, with mill heads averaging 2.25% Cu, 0.015 oz.Au, and O.4O oz, Ag. per ton.Summary and Conclusions:During the period Jnnuar-1 1971 to December 1973 inclusive the use of large cells at Opeminka have shown that metallurgy is comparable to when using conventional cells, Operating and maintenance costs are lower, An on stream analyzer with reagents controlled by computer, are being assessed further.Opej1atljn Of Cells:!lo cell level adjustments are required when tonnage is adjusted 20 to 25%.Depending on mill heads and grade of concentrate reagents are adjusted to the first rougher for metallurgical control. Reagents to second rougher and scavengers are seldom adjusted as feed to this section has a maximum variation of about 0.2'~ Cu.Power – Maintenance and Space Requirement :Our total power consumption for 3,400 T.P,D. flotation circuit for operation and air supply is 280 H.P. Previous power drawn using conventional cells was 400 H.P. at 2,000 T.P.D.Total maintenance costs for flotation circuit has averaged $1,100.00 per year for the 3 years of operation, this cost should remain constant.Floor space required for cells and walkways is 2,000 sq.ft.

Jan 1, 1974

By Ainul Akhtar, Steve Cockcroft, Daan Maijer, Carl Reilly, Lu Yao, Jun Ou

A coupled thermal-fluid flow-multicomponent model has been developed to aid in understanding the melting/dissolution behavior of solid Al-rich Material (TiAl) in a liquid titanium pool produced by an electron beam. The model is capable of accounting for the significant phenomena present affecting heat, mass and momentum transport including thermal and compositional buoyancy and Marangoni forces, Darcy attenuation, evaporation, melting and solidification, and the associated release or absorption of latent heat. The modeling results have indicated the compositional fluid flow driving forces (compositional buoyancy and Marangoni forces) contribute significantly to the melting/dissolution process. The model is waiting for validation against empirical data.

Jan 1, 2014

By Greg Gosson

These materials are provided for general information purposes only and do not constitute legal advice. Readers are advised to seek specific legal advice from their own counsel in relation to any decision or course of action contemplated. Outline ??What is meant by a ?current technical report? under NI 43-101? ??When is a current technical report required? ??Who makes the decision regarding whether a technical report is current? ??Examples of the types of information that make a technical report no longer current for securities filing purposes.

May 1, 2009

By V. J. Hucka, J. H. Tu

"A computer model has been developed for evaluating the performance of truck and shovel operations in an open-pit mine. The data required for describing the haulage network are simplified and shift startup and ending procedures specific to any given mine can be incorporated into the model readily . The model uses a FORTRAN-based simulation language SLAM and can be tailored to the conditions and practices of a particular mine.The model is used to analyze truck and shovel operations, evaluate different haulage layouts in the planning stage, or compare the expected performance of alternative truck dispatching systems.Stochastic simulation is used to model the random variation in time required f or the individual activities. This gives a more realistic representation of the processes under study. Simulation runs show good agreement with actual performance. The model is especially useful for examining alternatives in equipment acquisition , haulroad design, truck-shovel allocation and dispatching methods. The results of such simulations provide a sound basis f or making major management decisions.IntroductionTruck haul age is widely used in open-pit mining operations. It is also the largest cost item in the operating costs of an openpit mine, in some cases accounting for an estimated 50% of operating costs(1) , Truck replacements, which are necessary from time to time, involve large amounts of cap ital. Increasing depth of mining and consequent increase in stripping ratios require additional capital investment in the truck-shovel fleet. The sharp rise in energy costs over the last decade has also contibuted significantly to an increase in truck fleet operating costs . All these factors have led mine operators to search for ways to improve the effectiveness of the truck-shovel fleet, in order to lower costs and maintain a profitable operation in the face of declining markets and increasing world wide competition.Control of truck haulage in an open-pit mine is usually done in one of two ways."

Jan 1, 1985