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By A. Osouli, B. Moradi Bajestani

"Increase in permeability of rock mass is vital for both petroleum and geothermal applications. Hydraulic fracturing is a common method to create and increase the permeability for production. Due to the complexity of fracture propagation in a naturally fractured medium, understanding the interaction between hydraulic fracture (HF) and natural fracture (NF) is of great importance to optimize the fracturing process. The possibility of interaction between HF and NF is partly a function of orientation. Various scenarios are predictable for hydraulic fracture regarding the intersection with NF such as being arrested by NF, crossing NF or crossing the fissure while injecting water into it. Different parameters such as geomechanical and geometrical properties of surrounding rock mass, the operational parameters such as injection rate and the angle between created hydraulic fracture and natural fracture (approach angle) can affect the result of hydraulic fracture and natural fracture intersection. In this paper, using a series of flow-coupled Distinct Fracture Network (DFN) simulations, hydraulic fractures were analyzed to investigate the influence of the aforementioned parameters on the hydraulic fracture propagating. Results show that the most significant parameters affecting the interaction of natural and hydraulic fracture are orientation of the intersection as well as injection rate. The interaction and fracture propagation in NF and HF intersections are also studied and discussed in detail.INTRODUCTIONThe hydraulic fracture technology has substantially changed the oil, gas and geothermal industries. With the help of this technology, extraction of fossil resources from tight shale reservoirs will be economical, feasible and sustainable. Due to presence of massive oil and gas trapped in these reservoirs, this technology has been the center of attention for the past 40 years (King, 2012). Hydraulic fracturing is the process in which high pressure water is pumped into shale unconventional reservoirs with low to ultralow permeabilities. With this process paths are created in these mediums for delivering oil and gas to horizontal wellbore and increase the surrounding rock medium permeability. Economical and sustainable stimulation of these tight reservoirs is highly dependable on our understanding in regard to fracture propagation in the highly complex rock medium. Hydraulic fracturing process in rock mediums with preexisting natural fractures is more complex because of the high possibility of Hydraulic Fracture (HF) being arrested or deviated by Natural Fracture (NF). Also, HF and NF intersection can influence the required pumping pressure, injection rate, the outcome of horizontal wellbore and the affected geological underground zones. Since the 1950s, numerous studies have been conducted to predict and plan fracture propagation with the help of modeling and simulation methods. Having a thorough and accurate prediction of fracturing process will not only prevent stimulation of unwanted geological zones or pollution of aquifers, but also will improve the efficiency of the fracturing process. Previously, several studies have been conducted in order to investigate and analyze the interaction of hydraulic fracture and natural fracture (Cottrell, Hosseinpour, & Dershowitz, 2013; Doe, Lacazette, Dershowitz, & Knitter, 2013; Shakib, 2013; Zhang & Jeffrey, 2006)."

Jan 1, 2015

By Lawrence Devon Smith, Keith Spence, William Roscoe

"In March 2003 the CIM Council adopted and approved the document “Standards and Guidelines for Valuation of Mineral Properties” as developed by the Special Committee of the Canadian Institute of Mining, Metallurgy and Petroleum on Valuation of Mineral Properties (CIMVal). The document is referred to as the CIMVal Standards and Guidelines. The document evolved from a specific recommendation by The Mining Standards Task Force (MSTF) of the Toronto Stock Exchange and the Ontario Securities Commission in its Final Report (January 1999) that the CIM form a committee of valuation practitioners to review and advise on approaches to valuation of Mineral Properties. The CIMVal Standards and Guidelines are organized into two parts: •,Standards which are general rules in the Valuation of Mineral Properties. The use of the Standards is mandatory if the Valuation Report is stated to follow CIMVal (although not mandatory in the sense of having regulatory authority). Definitions are given at the beginning of the Standards. •,Guidelines which elaborate on the Standards and, while not mandatory, provide guidance and best practices which are highly recommended to be followed in the Valuation of Mineral Properties.CIMVal specifies requirements for the Qualified Valuator who has the responsibility for choosing the appropriate approaches and methods for the valuation of mineral properties. With regard to the specifics of the application and practice of valuation approaches and methods, CIMVal directs the Qualified Valuator to the large body of published papers, published valuations, presentations and court judgments to guide his or her choice. This is also the approach taken by VALMIN (Australia) and SAMVAL (South Africa). To facilitate the dissemination of industry practice, the CIMVal Committee organized a “Valuation Day” at the CIM Annual General Meeting in Toronto (Mining Millennium 2000), on March 8, 2000. Industry experts presented papers on valuation of Mineral Properties which were subsequently published in a proceedings volume and individually ad technical papers in the CIM Bulletin. The Management and Economics Society of CIM has continued to identify and publish papers on valuation in the CIM Bulletin and Magazine. The present document gathers in one place the CIMVal Standards and Guidelines, the papers from the 2000 Valuation Day, and a number of subsequent papers that illustrate industry practice for the valuation of mineral properties."

Jan 1, 2003

By J. E. Hawley, R. C. Hart

"The Preston East Dome gold mine is in the southeastern part of Porcupine district, Ontario, 5 miles southeast of Timmins, and immediately south of the property of Dome Mines, Limited.The claims now owned by this Company were originally staked in 1909. After the property had remained dormant for many years, the present Company was organized in 1936 to resume development operations. Two shafts had been sunk: at the time of the early work on the claims, but lateral work from these failed to reach the ore deposits. A successful diamond drilling campaign undertaken under the direction of D. G. H. Wright, however, was followed by the sinking of a five-compartment shaft arid the erection of a mill. From the start of operations to the end of 1944, 1,292,000 tons of ore averaging $11.60 in gold a ton have been mined.An outstanding feature in this mine is the occurrence of the major gold deposits in quartz porphyry intrusives, though minor deposits are also found in the adjacent Keewatin volcanics. Most of the ore occurs in fractures, but the filling was accompanied by varying degrees of replacement of schistose wall-rocks. The ore deposits may be classified as:"

Jan 1, 1954

By J. Shibata, N. Murayama, H. Yamamoto

As one of effective usages of wastes discharged in the non-ferrous metal industry, the syntheses of AlPO4-5 and hydrotalcite were carried out using aluminium dross as a raw material. AlPO4-5 is an aluminium phosphate condensate with properties of zeolitic materials and large pore size. Hydrotalcite is an inorganic anion exchanger and has a layered structure of complex hydroxide. They were synthesized in an autoclave at high temperature and pressure. Various physical properties such as crystal structure, surface texture, and specific surface area were measured. AlPO4-5 can be synthesized from aluminium dross under hydrothermal conditions at 180°C-200°C, and 3h. At the same time, AlPO4-34 and non-porous AlPO4 were also formed as by-products. The crystals of AlPO4-5 have a hexagonal structure. Lt is desirable to heat the reaction product at around 550 °C to remove tri-ethyl amine. The specific surface areas of the reaction product before and after heat treatment at 550°C were 17.9m2/g and 358m2/g, respectively. Hydrotalcite can be obtained by a co-precipitation method from the aluminium dross and waste MgCl2 solution discharged in the aluminium regeneration process. Small amounts of SiO2, Al2O3, and Fe2O3 remain in the reaction product as an impurity component. The interlayer distance of the obtained reaction product is about 0.3 nm. Hydrotalcite changes to Mg-Al oxide during calcination at 500 °C for 3h, and then hydrotalcite is formed again by a rehydration operation. The physical properties of the reaction products obtained from the wastes were very similar to those from fresh reagents.

Jan 1, 2004

By K. Poorhaydari, B. M. Patchett, D. G. Ivey

In this paper, some applications of carbon extraction replicas, as samples for transmission electron microscopy (TEM), are discussed. Modern high strength microalloyed (HSMA) steels, used as structural or pipeline materials, have very small grains with substructures. Replicas used in TEM can resolve the grain boundaries and can be used for grain size measurements in cases where the small size of the grains pushes the resolution of conventional optical microscopes. The grain size variations obtained from replicas correlated very well with mechanical property variations, indicated by hardness, in the fine-grained heat-affected zone and base metal of some welded HSMA steels. Replicas are also very suitable samples for precipitate examination with analytical TEM. Advantages and limitations of the application of replicas, as well as some corrections for the estimation of the volume fraction of fine precipitates, are discussed.

Jan 1, 2005

By John Battista

Uranium mining in Australia has a chequered history. This paper reviews the development of the Australian uranium mining industry from the 1930?s to the present day. It outlines the geology of the various deposits and the mining and metallurgical techniques used to extract the uranium. The industry is profoundly affected by government policies and the paper considers the roles of the Federal, State and local governments. The influence of public opinion on nuclear issues and the effects current and historical policies of various governments have had on uranium mining are outlined. Despite heavy restrictions placed on it, Australia?s uranium mining industry has maintained its place as one of the world?s largest producers. This paper also provides an outline of where the industry in Australia may be headed in future.

Aug 1, 2010

By N. Melnyk

IN the past, the Cadomin Coal Company has opened four mines, all in the same coal seam or its folds. Three of these were opened from river level by horizontal entries or rock tunnels, and the fourth, the present working mine, by vertical shafts. This paper deals largely with some operating phases of this fourth mine, with which the writer has been associated. The seam worked here is a thick, steep, bituminous seam, and the writer feels there is a paucity of published data on the mining of such seams. Possible reasons for this are that such seams do not !end themselves to intensive development or mining, there is little chance to mechanize because of the extreme pitch, and operations are fraught with many problems. In addition, the present operations in this particular seam are being carried on at a level below the former workings, introducing new problems, not en-countered on the upper level. Coal will, without question, long continue to be an important factor in the national economy, and some of the best coal is to be found in thick, steep seams. But with the exhaustion of the easily-mined coal near the outcrops, future coal will have to come more and more from lower levels. At Cadomin there is still considerable coal on the second level, below the old river-workings, and there is a possibility that, in the future, still lower levels will be worked. It is the purpose of this paper to indicate some phases of such lower-level operations and to invite discussion.

Jan 1, 1942

By Gaston Gingras

"IntroductionL'entretien de l'equipement minier dans les mines à ciel ouvert est une activité qui est aussi vieille que I'existence des mines et qui a progressé au cours des années pour suivre l'évolution des techniques d'exploitation. Lors de la mise en usage de s premières pelles à la va peur, celles-ci étaient généralement entretenues par I ‘équipe de quatre hommes qui était responsable de son opération. Pour les travaux plus compliqués ils utilisaient les services de machinistes qui eux savaient comment réparer Ie moteur à vapeur et couler des coussinets de ""babbit"". Les premières pelles diesel étaient entretenues de la même façon mais pour les réparations au moteur, on devait recourir au représentant du manufacturier qui était Ie seul à avoir les compétences nécessaires.Ce n'est vraiment qu ‘après la deuxième guerre mondiale que I ‘usage de l'équipement mobile s'est répandu dans les mines à ciel ouvert pour débuter les extractions selon les méthodes que I'on connaît aujourd'hui.L'entretien de l'équipement minier de façon organisée à débute avec I ‘usage de ces machines dans nos mines. Ces machines étaient un peu primitives, petites et pas très dispendieuses a I'achat. Même si la disponibilité était basse, elles fournissaient quand même un rendement qui en ces temps était acceptable. L’organisation de I ‘entretien de cet équipèrent était assez primitif et n'occupait qu'une place secondaire aux yeux de la direction de la mine."

Jan 1, 1988

By S. Amira

In the last two decades, many new creep-resistant magnesium alloys have been developed for high temperatures applications. Their mechanical performance and corrosion behaviour were reported for various experimental conditions. However, these conditions often led to uneven comparison basis. In the present study the microstructure, mechanical properties and corrosion performance of four of these newly developed creep-resistant magnesium alloys were systematically compared. Specimens were obtained from experimental box-like components that were die-cast and thixocast in comparable conditions. Their mechanical and corrosion properties were compared using similar testing conditions. Results show that the creep resistance, strength and impact resistance of specimens are comparable but systematically lower compared to specimens cast under optimized conditions. The reduced concentration of elements such as Al, Ca, Sr and Ce lead to a decrease of the corrosion resistance of the magnesium alloys in 3.5% NaCI solution.

Jan 1, 2007

By Pura Alfonso, Sarbast Hamid, Hernan Anticoi, Eduard Guasch, Josep Oliva

"Av. Bases de Manresa 61-63, Manresa (08242) Barcelona, SpainTantalum is a strategic metal and an improvement of the mineral processing is an important issue. The main objective of this work is to optimize the grinding technologies for tantalum ores with high pressure grinding rolls. The selected ore for this study was an altered leucogranite from the Penouta Open Pit Mine (NW Spain). In the present work mono-size experiments have been carried out using grinding rolls with controlled pressure. The particle size distribution has been monitored in the input and output of the high pressure grinding rolls for each experiment. The cylinder pressure that is transmitted to the particles has been determined. New population balance models are presented for high pressure grinding rolls with parameter adjust for tantalum ore. The obtained model uses the physical description of particles under the comminution action of the grinding rolls. The obtained results are in agreement with other models and the errors in the adjustment are low. The selection function proposed for this model describes adequately the breakage probability of the particles inside the high pressure grinding rolls. The presented model can be a good alternative for simulating a high pressure grinding roll process. INTRODUCTIONTechnology for grinding have been improved for many years, introducing new variables and parameters involving energy consumption, mechanical stress analysis of the compression particles or pressure application for optimizing the comminution (Morrell et al, 1997). High pressure grinding rolls is a modern technology that is proven to reduce the operating costs in full scale plants when compared with other milling technologies. Its benefits on energy saving and simplicity in the process have been studied and applied, first in the cement clinker industry (Abouzeid & Fuerstenau, 2009) and after in mining activities, especially in metallic ore deposits (Austin et al, 1991; Guevara & Menacho, 1992; Morrel et al, 1997; Torres & Casali 2009; Numbi & Xia, 2015). Many author structures of the High Pressure Grinding Rolls modelling in three main branches; (a) throughput modelling, (b) Power and energy model and (c) particle size distribution modelling (Austin et al, 1991; Guevara & Menacho, 1992; Austin & Trubelja, 1994; Morrel et al, 1997; Torres & Casali, 2009)."

Jan 1, 2016

By B. Burke

Magnesium and its alloys are attractive materials for use in automotive and aerospace applications because of the low density and good mechanical properties. However, difficulty in forming magnesium and the limited number of available commercial alloys limit their use. The present paper reviews the efforts to improve the attractiveness of magnesium through non-traditional processing, and presents preliminary results of current work on producing magnesium alloys via powder metallurgy P/M. P/M can be used to alleviate the formability problem through near-net-shape processing, and also allows unique chemical compositions that can lead to new alloys with novel properties. The feasibility of producing magnesium powder metallurgy products utilizing the industrially dominant process of mixed powder blending, uniaxial die compaction and controlled atmosphere sintering was investigated. An alloy composition based on the commercial Mg alloy AZ31 (3% Al, 1% Zn) was used to facilitate comparison to similar wrought products. The optimal processing conditions (compaction pressure, sintering time and temperature, and quenching temperature) were found to maximize sintered density and mechanical properties.

Jan 1, 2007

By A. E. M. Warner, A. Vahed, P. J. Mackey

In the decade 2002 to 2012 some 6.7 million tonnes of new copper concentrate production capacity was brought on line, corresponding to 2 million tonnes of contained copper. This increase in concentrate supply necessitated the commissioning of a number of new copper smelters as well as the modernization and/or expansion of existing plants to meet the demand. This paper gives an overview of the copper extractive industry, reviews recent copper production trends and changes in the copper industry, including an examination of pyrometallurgical and hydrometallurgical technology developments. WorleyParsons has supported a number of the projects involved in these developments and this role is briefly discussed. The paper introduces a number of ideas related to possible future directions of the copper industry.

Jan 1, 2014

By Joe Price

Canada?s energy future will increasingly depend on a supply of light, sweet crude oil derived from the Athabasca oil sands deposit of North-eastern Alberta. Billions of dollars are being spent on the construction of new and expanded mine and bitumen extraction plants, in situ recovery facilities, pipelines, upgrading installations and all the infrastructure needed to support these projects. The success of the existing operators has also inspired new players, anxious for ?a piece of the action? to come forward with exciting project proposals of their own. None of this investment and spin-off economic activity would be taking place today if events had unfolded differently in this part of the world some one hundred million years ago. The accumulation of sand in rivers, estuaries and in the near-shore marine environment created the great reservoirs that host the enormous oil deposits these projects are designed to exploit. Mine operators of all stripes will likely agree that there are few good ?geological surprises?. With specific reference to oil sand deposits, the geological history determines the distribution of sand, silt and clay bodies, which in turn controls the ore grade. Important design factors including everything from stable pit slope angles to tailings properties reflects events that took place millions of years before. An understanding of the sequence of events that resulted in deposition and preservation of the sediment and oil are important to sound design for both mining and in situ facilities. A geological history of the region is described. Site-specific examples from Syncrude?s operating mines are used to illustrate some of the geological factors that can present design challenges.

May 1, 2003

By M. Mirnezami, J. A. Finch, M. S. Hashemi A.

This study examined the effects of pH and sulphate concentration on the surface charge and stability of alumina and pyrite dispersions. The relationship between these properties was investigated using measurements of electrophoretic mobility and settling velocity. The maximum aggregation for both minerals was observed near the iso-electric point (iep) where the force of repulsion is at a minimum. Aggregation decreased at pH values away from the iep, where an increased surface charge causes electrostatic repulsion between particles. Zeta potential data revealed that sulphate ions were adsorbed only on positively charged surfaces for both minerals. Adsorption of sulphates on the alumina surface increased aggregation by reducing the surface charge from >+25 mV to close to zero. These results indicate an electrostatic bonding of sulphate ions to alumina surface. Preliminary results on the interaction of pyrite and sulphate ions indicate a similar response.

Jan 1, 2004

By T. Thriveni, Ji Whan Ahn

"The current advanced technologies for the manufacture of light weight metals processing significantly increasing and attributes to the safety, performance, recyclability and economy. Still lack of technologies developed for light weight metals processing waste utilization and application. Environmentally friendly methods need to develop for better understanding the processing waste utilization. Alumina and aluminium processing creates a wide range of waste products, the most significant being is red mud. Bauxite residue is a high volume hazardous waste and nearly 3 billion tons have been dumped worldwide. Approximately, 120 Million tons/yr of red mud being produced without any environmental sustainable solution. Currently the most significant technology is waste utilization. The bauxite residue is suitable for road base construction, golf bunker sand, back fill and, general fill. Sustainable recycling technologies are necessary for the bauxite residue utilization for the recovery of rare earth elements and cement materials. Carbonation or CO2 sequestration of carbon dioxide is a method pioneered for the bauxite residue is modified to reduce alkalinity. The carbonation of alkaline material is an inexpensive and safe process that leads to the formation of thermodynamically stable products. The use of the carbonation can be an advantageous solution for environmental climate change and sustainability problems in the new century.INTRODUCTIONIn 2014, bauxite consumption was estimated to be 9.6 million tons, nearly all of which was imported, worth an estimated 269 million dollars. More than 95% of the bauxite was converted to alumina, and the remaining 5% went to non-metallurgical products, such as abrasives, chemicals, proppants, and refractories. Global aluminum demand is growing steadily spurred by growth in India and China (RBCAluminum Market Outlook, 2013) (Figure 1). Aluminum consumption is expected to rise 5% annually through the end of the decade, reaching 67 million tons per year by 2020. Global bauxite production decreased by 17% from that of 2013, principally owing to lower production in Indonesia. In response to a Government ban on exporting bauxite and other unprocessed mineral ores that took effect on January 12, 2014, bauxite mines throughout Indonesia shut down and production decreased from 55.7 million tons in 2013 to an estimated 500,000 tons in 2014. The ban was part of a mining law that was instituted in 2009 to increase development of downstream processing facilities in Indonesia."

Jan 1, 2016

By M. Mahfoud

The effect of grain refinement on the tensile and fatigue crack propagation behavior of sand cast magnesium alloy AM60B has been investigated in the present study, C2Cl6 in the amount of 0,3% was used to grain refine the melt, The fracture toughness tests were conducted in laboratory air at room temperature (25°C) using a sine-wave cyclic frequency of 20Hz and a load ratio of R = 0,1, The response in the Paris's regime and the critical stress range were determined, Preliminary findings have shown that C2Cl6 has a significant effect on both the tensile properties and fatigue crack propagation of the alloy tested, Grain refinement increased both the yield and ultimate tensile strength by more than 46%, and decreased the crack growth rate from 2,7 to 1,4 MPa Vm , However, the grain size seems to have a smaller effect on threshold stress intensity factor range. The fracture surfaces of specimens were examined optically and under the scanning electron microscope (SEM) to determine the relationship between grain size and fatigue properties.

Jan 1, 2005

By R. Browner, J. Collard, D. Ibana

The extraction of cobalt from synthetic pressure acid leach solutions of nickel laterite ores by the direct solvent extraction route using ESPLIM is reported. It first explored the use of gaseous ammonia as pH modifier and then the variables that affect the dispersion of the aqueous phase in the organic phase such as ionic strength, viscosity of the phases, initial droplet size, etc. were explored so that phase hold-up and thus extraction can be effectively controlled. The results show that the technique allows better control of phase dispersion circumventing one of the main weaknesses of conventional solvent extraction.

Jan 1, 2005

By D. B. Johnson

Acidic, metal-rich waters generated at working metal mines and abandoned mine sites are generally considered to be major pollutants of the environment. However, the metals they contain often have significant value of their own, or as sources of useful mineral products. We have developed novel bioreactor systems that facilitate the selective recovery of various transition metals (e.g. copper, zinc and iron) as defined minerals that can be recovered and recycled. The bioreactors use novel species of acidophilic bacteria. Ferrous iron is oxidised by Ferrovum myxofaciens, a specialist bacterium that forms large amounts of exopolymers and grows as filamentous streamers in flowing mine waters, and the ferric iron generated is precipitated as the mineral schwertmannite, a small proportion of which is used to remove any arsenic present in mine water. Copper and zinc are precipitated as sulphides using H2S generated by consortia of acidophilic and acid-tolerant sulphate-reducing bacteria in a continuous flow, on-line low pH bioreactor. Transition metal sulfides can be segregated by precipitating them, either on-line or off-line, at different pH values. The modular units that have been developed can be configured to treat mine waters of different chemistries. A hypothetical acidic (pH 2.5) mine water stream containing 500 mg/L iron, 100 mg/L of copper and zinc, 50 mg/L of aluminum and manganese, 2 mg/L of arsenate, and discharged at a rate of 10 L/s, is used as an example of the potential application of the mineral-generating bioreactors. The environmental benefits and economic implications of considering mine waters as resources rather than wastes are discussed.

Aug 1, 2013

By N. Shi, T. G. Joseph

ABSTRACT A revised equilibrium approach to evaluate dipper-ground interactions during the dig cycle of ultra-class mining shovels operating in soft unblasted uniform ground conditions is presented. A review of previous approaches, leading to an outline of the modifications and ground condition considerations, is made in support of the reasoning and basis for the derivation presented. An analytical solution is provided to the scenario of a cable shovel dipper digging in soft ground material such as oil sands.

Jan 1, 2012

By M. Cai

"It is well known that Peak Particle Velocity (PPV) plays a critical role in triggering rockburst damage in burst-prone underground mines. To estimate the PPV distribution around excavations, advanced numerical modeling can be used. In wave propagation numerical modeling, velocity field is often assumed to be uniform around an excavation. However, it is observed that wave velocities near mine openings are not constant, but rather non-uniform. Wave velocity in a rock mass depends on many factors such as rock quality and confinement. In particular, confinement has a large influence on wave velocity. The confinement around an excavation is low at the wall boundary and increases gradually and reaches a constant value far away from the excavation boundary. Hence, stress redistribution due to excavation will have a profound influence on wave propagation in underground mines. A better understanding of the influence of excavation effect on wave propagation helps to interpret the field observation of rockburst damage and improve mine safety. For this purpose, a non-uniform velocity model need to be constructed and the influence excavation effect should be taken into account in numerical wave propagation modeling.In the present study, a non-linear velocity model is developed firstly by considering the influence of confinement on wave velocity. This model links wave velocity to confinement explicitly. A coupled numerical method is then developed and used to study the seismic wave pattern around excavations in underground mines. Two codes, FLAC and SPECFEM2D, are coupled in the analysis. The motivation of developing the FLAC/SPECFEM2D coupled approach is to take merit of each code, such as the stress analysis capability in FLAC and the powerful wave propagation analysis capability in SPECFEM2D. The coupling process is realized through three steps: (1) static stress redistribution around an excavation is analyzed in FLAC; (2) data for coupling analysis, such as non-uniform velocity field (based on the new developed velocity model), mesh, absorbing boundaries, etc., are generated by FISH functions in FLAC and passed to SPECFEM2D; and (3) wave propagation modeling is performed in the SPECFEM2D considering a fault-slip seismic source. Because stress redistribution around the excavation is considered, non-uniform velocity field for the SPECFEM2D model can be obtained and this is a notable feature of this study. Very large difference in the S-wave response in these two modeling approaches with uniform and non-uniform velocity fields can be seen from the modeling results.Using the FLAC/SPECFEM2D coupled modeling approach, accurate velocity models can be constructed and this in turn will help to produce accurate PPV distribution around the excavations. Accurate PPV contours can be used to identify high rockburst risk zones for improved dynamic ground support strategy."

Jan 1, 2015