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By Cheowchan Leelasukseree

Mae Moh mine, operated by Electricity Generation Authority of Thailand (EGAT), is the largest open pit mine in Southeast Asia. Its production is approximately 15 million lignite tons and 90 million m3 of waste, annually. The bottom of the final pit limit is designed to be approximately 500 m in depth. Presently, the pit depth is almost 250 m below original surface. The complexity of geological structures, such as faults, has caused a number of geotechnical difficulties. In a challenging lowwall area, called Area 4.1, an inclined weak bedding plane, G1, will be daylighted along the lowwall as following by mine plans. The dimensions of Area 4.1 are nearly 300 m wide and 90 m high. The friction and dip angles of the G1 interface are reportedly 12° and 15°, respectively. A three million m3 claystone block, resting above G1, would potentially slide down, and possibly cause a massive failure. EGAT engineers are acutely aware of the potential gigantic sliding failure and are modifying the mine plan in Area 4.1 to improve mine safety and minimize the displacement of the potential sliding block, reduce the possibility of failure and lower the additional mining cost as much as possible. The cut and fill mining technique was selected and studied to achieve those goals for mining in Area 4.1. With this mining technique, G1 will be partially daylighted. Therefore, an arch formation is induced with a sliding block above the mining area, which could perform as a temporary support undercutting a certain span. Initial studies of the behavior of the partially undercut slope are presented in this paper, along with a review of the similar failure history in Mae Moh mine and a 3-dimensional numerical model of the mine. The failure history review provides an estimation of undercut span without failure. The three-dimensional numerical model results, using 3DEC, gave an initial approximation of the displacement of the sliding block in Area 4.1. The next exciting study of the behavior of partially undercut slope is a trial undercut slope field experiment in Area 4.1. Currently, a trial undercut slope field experiment in Area 4.1 is under construction. In the field experiment, a number of monitoring programs will be installed in Area 4.1 to monitor and obtain information to allow a better understanding of the behavior.

Jun 1, 2012

By William Skinner, Jim Pae Lem, Massimiano Zanin

It is well known that the specific density of minerals has adverse influence on the classification performance of a hydrocyclone, particularly when liberated high density minerals such as gold or uranium are present in sulphide ores. These liberated heavy minerals often misreport to the underflow and recirculate to the system. Such phenomena does result in serious issues in a closed-grinding circuit, such as overgrinding, leading to production of flaky particles (as in gold) or ultrafines, in addition to increased energy inefficiency. In plants which present gold liberated at coarser size, loss of gold due to cyclone inefficiency is sometimes prevented by incorporating gravity concentrators into the grinding circuit to recover the gold. The work reported in this paper looks at whether the effect of density will prevent successful rejection of liberated U-bearing minerals in the –10µm size range of a plant re-cleaner feed, which is necessary to minimize penalty U accumulation in a copper concentrator. The study was carried out using a cyclone rig with spigot diameter of 0.25 inches in combination with batch flotation. It was found that the density effect is almost negligible at particle sizes below 10µm. Consequently, the liberated U-bearing particles finer than 10 µm were successfully removed in the overflow stream as rejects and hence U grade in the copper concentrate remarkably reduced, by 16 ppm. Based on the results, de-sliming of the re-cleaner feed was recommended for plant trial and implementation.

Jan 1, 2016

By Maurice A. Roche

Introduction Most of the Flin Flon ore-body, like many others in northern Canada, was covered by water. The original discovery was made where the ore-body outcropped on a strip of land jutting out into Flin Flon lake. The outcrop could be traced for a distance of 600 feet across the strip of land, but disappeared under the lake on both sides of the peninsula. Following the discovery or location of the property, in 1915, and subsequent to its examination by the H.P. Whitney interests in 1925, an extensive diamond-drilling programme was completed, which proved the existence of an ore-body at least 2,600 feet long and 900 feet deep. In plan, the central part of the ore-body at surface attains an overall width of about 450 feet; including waste horses, and gradually becoming narrower to the south. To the north, it stretches out as a much narrower tongue. The main body is a solid sulphide ore containing gold, silver, copper, and zinc. Adjacent to, and on the footwall side of, the solid sulphide ore-body, there are considerable widths of talcy disseminated copper ore, particularly in the upper 300 feet of the deposit, where the maximum widths occur. The ore-body occurs in a greenstone area, the rock being quite hard on the hanging-wall side, with the footwall schisted, talcy, and much softer. The greater part of the ore-body was overlain by 12 to 15 feet of water and from 15 to 90 feet of mud and clay, this material requiring eventual removal, regardless of the system of mining adopted. The total of mud and clay overburden was estimated at 1,000,000 tons. After considerable study, it was decided to mine the upper 300 feet of the ore-body by open-pit methods; the balance of the ore to be recovered by underground mining . The present paper gives an account of the methods adopted in both operations, and of the problems encountered.

Jan 1, 1935

By Donald F. MacDonald

THE cement plant nearest to Nova Scotia is not far from Montreal. Cement is a heavy product which, because of its relatively low value, cannot stand a high freight charge without unduly enhancing its cost. This is one reason why cement costs are high in Nova Scotia. The regular retail price per bag (8772 lb.) in Antigonish is 85 cents, which would be $3.40 per Canadian barrel of 350 pounds, or $3.65 per American barrel of 376 pounds.It is said that the lowest wholesale price in Halifax is 65 cents per sack, which would be $2.60 per Canadian barrel or about $2.80 per American barrel. According to U.S. Bureau of Mines statistics, the average factory price for cement in 1937 was $1.48 per American barrel, which is practically the same as the value per barrel indicated in Dominion statistics for the Canadian output during that year. The difference between $3.40 and $1.48 is $1.92. It is evident that the average user of cement in the Mari-times pays a stiff premium because Maritime cement raw materials have not been developed. Rock-wool, the manufacture of which is rapidly increasing in Ontario and the United States, is much needed for building insulation in the cold climate of Nova Scotia.

Jan 1, 1939

By K. Himbeault, D. Campbell, N. C. Garisto, D. A. Orava, A. Rosaasen

"The level of scientific knowledge about the effects of contaminants is increasing and changes in environmental monitoring are likely to allow for the assessment of environment effects particularly to the aquatic environment. This paper provides an overview of recent developments in this area which include the environmental effects monitoring program for pulp and paper operations, the assessment of the Aquatic Effects of Mining (AQUAMIN) program, the Aquatic Effects Technology Evaluation (AETE) program, and the review of the federal Metal Mining Liquid Effluent Regulations (MMLER). The paper also provides a look forward at the direction of environmental monitoring of mine projects in Canada. IntroductionEnvironmental monitoring programs provide a wide range of data to environmental management systems, regulatory authorities, and stakeholders. The data obtained are used to demonstrate that operations are in compliance with regulatory environmental protection requirements, and provide the scientific basis for assessing the effectiveness of environmental protection measures. Environmental monitoring requirements for mine projects are established based on the type of operation, site specific issues and concerns, and the requirements of regulators and mine proponents.The level of scientific knowledge regarding the potential effects of contaminants on the receiving environment is increasing, and in particular with regards to the receiving aquatic environment. Regulatory controls regarding the protection of fish, fish habitat, and fishery resources are being reviewed with regards to their adequacy, and the environmental effects monitoring program on the pulp and paper industry is expected to provide useful data relevant to those types of operations. These developments are of interest to mine proponents as it is presently expected that an environment effects monitoring program will be developed specifically for the metal mining industry under a regulated environmental effects monitoring program as part of the Fisheries Act. This paper reviews recent developments in this area, and provides a look forward on the future directions of environmental monitoring programs."

Jan 1, 2000

By C. O. Aksoy, P. M. Ozfirat, M. K. Ozfirat, C. Tatar, C. Pamukcu

"Temporal and other factors contributing to the occurrence of occupational accidents at an underground coal mine in Turkey between 1992 and 2000 have been analyzed. The time period of the study spanned the transition from hand-worked mining methods (1992 to 1996) to hand-worked mining methods and mechanized mining methods (1997 to 2000).The mine selected for the study employed an average of 5,835 men per year on three separate eight-hour production shifts for 302 d/y (Sundays are not worked, and there are 11 holiday days per year). Production on an annual basis averaged 190,000 tons per year between 1992 and 1996, and 300,000 tons per year between 1997 and 2000.The purpose of the study was to determine which, if any, of the factors studied contributed to the occurrence of accidents so that the mine could take the necessary steps to reduce the risk to the workforce. Regression analysis was used to determine the strength of the relationship between each factor studied and the number of occupational accidents.The strongest relationships observed were between the age of the employee, the day of the week, and the total yearly labour."

Jan 1, 2006

By J. R. Rodda

Stainless steels are widely used to handle concentrated sulphuric acid (H2SO4) solutions produced in the manufacturing process, The majority of corrosion rate data published for stainless steel in product acid conditions is typically complied in tables or in iso-corrosion diagrams (iso-corrosion rates plotted as a function of temperature and H2SO4 concentration), without any reported consideration as to the accuracy and relevance of the method used to obtain the data, Given the characteristic potential cycling associated with the active-passive corrosion behaviour exhibited by stainless steel in hot, concentrated H2SO4, weight loss is considered to be a more reliable method than electrochemical measurements to measure corrosion rates, Consequently, an effort is made herein to demonstrate the accuracy and relevance of weight loss to determine laboratory corrosion rates in product acid conditions.

Jan 1, 2010

By G. J. McTeer, D. L. Verhelst, D. J. Rioux

Teck Metals Ltd. operates an integrated zinc-lead complex at Trail, British Columbia, Canada. Since 1997, KIVCETTM flash smelting technology has been utilized for the treatment of zinc plant residues and lead concentrates. Trail Operations’ furnace uses four water-cooled jackets for bullion tapping. This paper provides an overview of KIVCET bullion tapping for the past 16 years, and discusses successes and challenges encountered with respect to operations, training and monitoring.

Jan 1, 2015

By W. B. Agocs

"AbstractThe airborne magnetometer data of the Marmora iron ore deposit at Marmora, Ontario, have been used as an example to show the mapped results obtained by the use of line spacings of from 1 mile to 14 mile. The maps are illustrative of the results which could be obtained from such line spacings for any type of geophysical survey, and they show the probability of 'missing' a feature of economic value if the line spacing is too coarse.The probability equations are given for the crossing of randomly oriented features whose maximum dimension is less than the spacing of the control lines for circular, elongate, and rectangular outlines. The equations are P = D/S; P = 2L/S; P = 2(L+W)/,.S; P = A/,.S; P = (2L(S+T)-L2),.ST; and P (D(S+T-,.D)) ST, respectively; where P is the probability; D is the diameter; L is the length; W is the width; and S and T are line spacings.IntroductionTHE EFFECT of station spacing, and the effect of the distance between the plane of observation and the plane of the source of the potential field anomalies, have been studied by geophysicists in the past.The purpose of this paper, however, is to illustrate the effect of line spacing •on the resultant mapped magnetic anomaly for a known magnetite mass, and to present the elementary probability equations for determining the optimum control spacing for detecting a particular type of feature. The effect of line spacing which is illustrated by the magnetic maps presented herewith would be comparable to results which would be obtained by any geophysical survey, since the contours between lines are of necessity interpolated."

Jan 1, 1955

By Ho-Sung Yoon, Jyothi Rajesh Kumar, Jin-Young Lee

"Global population is a key factor in future energy requirements, especially considering the important elements of global energy resources, electricity production, the accessibility/non-accessibility of electricity, greenhouse gas emissions and the states of nuclear reactors. Everyday human requirements depend on industrial products, and industries need a considerable amount of electricity to run. Nuclear fuel is inexpensive and bolsters industrial growth. As uranium reserves are being consumed rapidly, an alternative source of energy in the nuclear industry is thorium. Here, primary energy supplies by various sources from 1993 to 2011 as well as estimates of future needs to 2020 are discussed. This study finds that primary energy sources are mainly fossil fuels, renewables sources, and nuclear and hydro energy. In addition, growth depends on increases mainly in renewable sources.Recovery of thorium from its ores by using hydrometallurgical routes were described and discussed. The final part of this paper was presented a case study of the thorium extraction from Korean monazite ore leach liquors by using Prieme JM-T diluted in A150 diluent as an extractant system. And possible separation of the thorium from rare earths (REs) and base metals were calculated by measuring of separation factors and finally, the recovery of thorium from loaded organic of Prieme JM-T was established.THORIUM IS FUTURE NUCLEAR FUEL?Global energy consumption is increasing everyday with the high population growth, high industrialization of numerous countries and the higher level of good and services consumption that follows it. If we look at specific sectors of the economy, oil consumption grew by 0.8 million barrels per day, globally, whereas the increase was 0.4 % for natural gas and coal 1.8 % for nuclear power and just under 2.0 % for hydroelectric power (Asheley 2009). Use of renewable sources of energy for power generation and transportation increased by 3% in 2014 (BP 2015)). Thus alternative source of energy must be identified and developed to meet this increasing demand. Thorium is a potential one for the nuclear industry."

Jan 1, 2016

By W. Torres Pino, L. Mariscal Samaniego

The Ilo Smelter has been continuously operating since 1960 with Reverberatory furnaces and Pierce Smith converters producing blister copper. The original installed capacity of 1.134 tons per day of concentrated was expanded in 1976. A process of modernization started in 1995 and 1998 with the installation of an El Teniente Converter, a sulfuric acid plant and an oxygen plant to reduce the gaseous emissions to the atmosphere. With the official approval of the Environmental Compliance and Management Program (Programa de Adecuaci6n y Manejo Ambiental - PAMA) in January 1997, Southern Peru Copper Corporation made a commitment to capture 91. 7% of the S02 generated at the smelter by January 2007. After an evaluation of six different technologies, the ISASMEL T process was selected because it can be easily adapted to the present operation, has a lower capital cost and it is a simple process. The fast learning curve to reach the total capacity will allow to fulfill the PAMA commitment in time. The project construction is in process and SPCC is prepared for a successful start-up and transition of the current operations at the end of year 2006. This paper outlines the factors considered by SPCC in its choice of ISASMEL T technology and describes the construction and the start-up activities of the new facilities.

Jan 1, 2007

By David Stone

North American Palladium is the owner/operator of the Lac des Iles mine located 115 km north of Thunder Bay, Ontario. The mine has produced an average of 65,000 ounces of palladium since 1994. Lac des Iles is currently undergoing the first phase of a major expansion that will increase ore production from 2,400 tons per day to 15,000 tons per day. A future expansion is being contemplated for 30,000 tons per day. The current expansion will increase palladium output to 250,000 ounces per year. The mine plan for the ultimate pit results in an excavation 1 km long by 800 m wide and over 450 m deep. This makes the ultimate pit at Lac des Iles one of the ten deepest open pits in the world, and the largest in Canada. This paper outlines the geotechnical data collection and design methodology for the ultimate open pit at Lac des Iles.

May 1, 2001

By K. Sakai, M. Miyaue, T. Aoki, T. Tani, S. Tanaka, N. Kudo

In the planning stage of a tunnel, due to limited available technology in the geological survey and the financial restriction, tunnel supports are often designed from unsatisfactory information, and the tunnel construction is started. Therefore, "observational construction" is carried out in the construction stage, in which the design is rationally verified and modified by observations/measurements. Moreover, the ground conditions ahead of a tunnel face must be predicted for efficient and safe tunnel construction. The authors have examined effective prediction methods to the ground conditions ahead of a tunnel face under construction of a mountain tunnel (Aoki et al., 2010) in view of the established method (Schubert et al., 1995). Though the prediction method of Schubert et al. requires the displacement in the direction of tunnel axis, it is difficult to obtain its accurate data by the electro-optical distance meter. Then, we have proposed a method that uses tilt sensors installed at the tunnel crown near the face to obtain the slight tilting information. To measure inclination of the tunnel crown, this inclinometer was originally developed as a daily management measurement, such that the geological condition and its possible change behind the face could be detected early, and a steady advance and construction safety could be ensured. This paper describes the method of forward prediction mechanism and advantages of this proposed method. It then presents the typical results of a field demonstration test at a tunnel under construction. Lastly, the predictable range from the stratum boundary at which ground stiffness changes are discussed based on the results of three-dimensional numerical analysis.

Jan 1, 2015

By H. B. Lumsden

This paper is intended to deal merely with the commercial development of some of the principal non-metallic mineral resources in the three prairie provinces- Manitoba, Saskatchewan, and Alberta. Coal is not included in this summary. Building Stone First and foremost, mention may be made of the building stone now being produced at Tyndall, Manitoba. This is a mottled limestone and is declared by experts to be one of the finest building stones in America, both as regards durability and appearance. It has been used very extensively both for exterior and interior work, not only in western Canada, but also in the principal cities as far east as Montreal. The stone is the "'Upper Mottled Limestone", which forms the summit of the Trenton (Ordovician) strata in the Lake Winnipeg basin. Quarries are at present being operated at Garson and Tyndall . The area where this stone is known to be available extends in a north and south direction for a distance of three miles, and the main productive ridge is probably about one half mile wide. The outlook for the future of the industry is extremely promising, as the stone is becoming increasingly popular in Eastern Canada, more particularly for interior work.

Jan 1, 1928

By Celine Y. Zhang, Chloe J. Feng, Charles Q. Jia, Donald W. Kirk

Oil sands petroleum coke (OSPC) is a by-product of coking - a high-temperature process that converts the mined bitumen to the synthetic crude oil (SCO). For every barrel of the SCO produced, about 20 kg of OSPC are generated. Over 70 million metric tons of OSPC have been produced and stockpiled as a result of the development of oil sands industry in the past few decades. Unlike conventional petroleum coke, OSPC has uniquely high impurity contents, particularly sulphur (~ 7 wt%) and metals (e.g. vanadium at ~0.15 wt%), which has hindered its large-scale applications as a solid fuel. Vanadium is a valuable metal that is widely used as an alloy for strengthening steels. The stockpiled OSPC contains about 100,000 tons of vanadium, while the world’s production in 2013 was only 75,600 tons. At the current price of $25US/kg, the OSPC-bound vanadium represents a total value of $2.5 billion US dollars. In this work, we investigate the technical feasibility of extracting vanadium from OSPC. The work focuses on the characterization of vanadium in OSPC and the conditions for effective extraction of vanadium from the OSPC.

Jan 1, 2015

By H. Hejny

Given the current status of political discussion in Europe about raw materials issues, the sustainable development of the extractive industry and the reduction of its environmental and societal footprint are among the key topics in this discussion. In this context, the European Commission approved the EO-MINERS project (Earth Observation for Monitoring and Observing Environmental and Societal Impacts of Mineral Resources Exploration and Exploitation). The overall aim of EO-MINERS is to bring into play EO-based methods and tools to facilitate and improve interaction between the mineral extractive industry, authorities, and the society in view of its sustainable development while improving its societal acceptability. Developing generic, standardised and reliable EO-based products to monitor the environmental and societal footprint of mining projects is the way chosen by EO-MINERS to improve this interaction, along with the organisation of tripartite meetings gathering all relevant stakeholders. The project uses existing EO knowledge and carries out new developments on three demonstration sites (Sokolov lignite mining area, Czech Republic, Witbank coal field, South Africa, Makmal gold mine, Kyrgyzstan) to further evaluate and demonstrate the capabilities of integrated EObased methods and tools in monitoring the environmental and societal footprints of the extractive industry during all phases of a mining project, from the exploration to the exploitation and closure stages. It contributes providing reliable and objective information about affected ecosystems, populations and societies, to serve as a basis for a sound ?trialogue? between corporate stakeholders, governmental organisations and societal stakeholders. The project already developed a set of consolidated indicators based upon previous knowledge about mining-related issues along with interviews of national, regional, and local stakeholders. These indicators reflect known environmental and societal issues at mining sites as well as the interest of various relevant stakeholder groups. The process described in the EO-MINERS project ? policy assessment > indicator identification > choice of suitable EO tools able to serve monitoring task > monitoring by EO tools > making available objective information for fair dialogue among stakeholders ? is generally applicable to all stages of a mining project. The key to success will be the right choice of indicators addressing the problem and subsequently the right choice of suitable EO tools and finally the willingness of all stakeholders to find a common solution. To this end, the EO-MINERS project organises site-specific ?trialogue? workshops at each demonstrations site, which aim to provide relevant information in adequate quality to the stakeholders as common ground for discussions. Local stakeholders, including mining companies, regulatory bodies, and community representatives are invited to participate in these workshops where the relevance of the developed EO-based products to environmental and societal impact assessment will be discussed. The presentation will discuss results obtained during these trialogue workshops, as well as the success and difficulties and reluctances encountered. The project will further indicate ways and means how the EO products and other project results may be used for monitoring purposes in all phases of a mine.

Aug 1, 2013

By T. Johnson, K. Lambrych, D. Kelley

Materials for construction of equipment used in hydrometallurgical plants are selected based on a combination of their ability to perform as required in aggressive process environments as well as their cost. As a material of construction, fiber reinforced plastic (FRP) has been shown to provide equal if not improved durability relative to alternative materials such as corrosion resistant alloys at a considerably lower cost. This is particularly true in the case of equipment used in acid leaching processes for copper, cobalt, nickel and rare earth elements. The selection and extensive use of FRP over alloys in new hydromet plant construction in North and South America illustrates this advantage of FRP effectively. This paper will compare corrosion performance and cost of plant equipment fabricated with stainless steel alloys and FRP made with Epoxy Vinyl Ester thermoset resins. Real world case histories for FRP piping, storage tanks, extraction vessels, and electrowinning cells combined with laboratory based corrosion studies will be reviewed to demonstrate how FRP materials are selected for hydrometallurgical equipment.

Jan 1, 2015

"Le présent article porte sur la diminution des rejets de concentrateurs produits durant l’exploitation et le traitement des minerais métalliques.Le minerai dilué envoyé au traitement a, très souvent, un certain pourcentage du stérile qui affecte directement la rentabilité des opérations souterraines et amplifie l’impact négatif sur l’environnement. Les essais de la séparation du stérile et du minerai effectués en milieu dense sur quelques types de la minéralisation d’or, ont démontré les deux possibilités qu’offre cette technique:• Dans le cas d’un minerai riche, il a été possible de séparer la part importante du toutvenant (minerai dilué contenant le minerai et le stérile) provenant de la dilution, tout en ayant un taux de récupération élevé (supérieur à 96%).• Dans le cas d’un minerai ayant une teneur sub-économique à cause d’une dilution importante, il est possible de produire un concentré ayant une teneur économique à l’entrée de l’usine de traitement, en éliminant une partie du tout-venant.En plus la séparation du stérile peut accroître, en outre, la rentabilité de l’exploitation minière, car le fait d’éliminer la partie de stérile le plus tôt possible diminue certains coûts (transport, traitement et autres). On conclue que la pré-concentration du minerai (séparation du stérile et du minerai) est probablement une seule solution actuellement étudiée qui diminue l’impact environnemental de la mine, sans avoir des conséquences négatives sur la rentabilité de l’exploitation souterraine."

Jan 1, 1997

By Y. Jiang, B. Li, R. Liu

"In this study, laboratory flow tests were conducted on 2-D artificial rock fracture network models containing a single intersection constituted by two inlet and two outlet branches. Three models with different intersecting angles of 60°, 90° and 120° were tested using both dye solution and distilled water. Constant flow rates were imposed on one inlet, and the flow patterns in the fracture intersections were captured by using a CCD camera. The test results were compared with the predictions made by numerical simulations that solved the Navier-Stokes equations. The results revealed that when Reynolds number (Re) is as low as less than 1, the intersecting angle has negligible influence on the flow rate of each branch and the flow patterns within a fracture intersection. As the interesting angle ? and Re (e.g., from 10 to 200) change, the normalized flow rates of different outlet branches change significantly, due to the inertial effect of fluid flow. These changes could be represented by a series of mathematical expressions involving Re and ?, which could be applied to fracture network models to improve their prediction accuracy on hydraulic properties (e.g., permeability and breakthrough curves of particles) of rock masses. INTRODUCTIONCoupled stress, flow, heat and mass transport are the corner stone subjects for many geoscience and geo-engineering disciplines, such as geological disposal of radioactive waste and geothermal energy exploitation. Many outstanding issues need to be investigated to enhance the knowledge on these subjects, and specifically more in-depth research in testing and modeling of the fluid flow in fractured rock masses is needed. In recent years, discrete fracture network (DFN) models have been extensively used to study the fluid flow and mass transport behaviors of fractured rock masses (e.g., Min et al., 2004; Zhao et al., 2011). In these models, each fracture is usually represented by a parallel-plate model, in which fluid flow exactly follows the cubic law. Therefore, comparative flow rate in each outlet branch of an intersection in these models only depends on its aperture. In reality, due to the surface roughness of fractures, the magnitude of mechanical aperture is usually larger than that of the hydraulic aperture of each fracture (Li et al., 2008; Xiong et al., 2011), and abundant flow patterns could exist in an intersection, influenced by its geometry, varying with changing Reynolds number (Re) (Kosakoswski & Berkowitz, 1999). Recent studies have also revealed that different mixing patterns might exist at a fracture intersection, bounded between streamline routing model and complete mixing model, that determine the final distribution of solutes in fractured rock masses (Johnson and Brown, 2001; Park et al., 2001). Numerical simulation has been the principal method adopted in previous studies, and the studies conducting flow tests on intersected fractures are less reported (Wilson & Witherspoon, 1976; Johnson and Brown, 2001). In this study, laboratory flow tests and numerical simulations by solving the Navier-Stokes equations were conducted on 2-D models containing a single intersection constituted by two inlet and two outlet branches, intersected at different angles. The main objective is to study the influence of intersecting angle on the flow behavior of the intersected fractures and the variations of flow patterns and fluid redistribution in each model along with the changes of the Re and the intersecting angle ?. The influence of surface roughness was not considered."

Jan 1, 2015

By D. R. Murray

"In 2017, Nutrien Allan Potash remediated a portion of the concrete liner in the production shaft. A set of underslung work platforms and collection boxes were used in conjunction with hydraulic splitters, jackleg drills and hand chippers to excavate and remove the broken concrete. New concrete was placed with the original pressure relief design, using a shaft slip form. Shortly after excavating, it was found that the estimated breaking rate and amount of original concrete in-situ was under estimated. Fifteen feet of excavated concrete (2719cu.ft) and ten feet (of replaced concrete was completed on April 28, 2017, and operation of the production shaft was returned to mine operations. During February 2019, Nutrien Allan Potash began remediation of a portion of the concrete liner in the service shaft. The project is different than the 2017 project, as the remediation has occurred during normal running operations and occurred only on night shift. Rather than hydraulic splitters and hand chippers, the new method includes a concrete saw and mechanical excavator from a working platform. The selected method is based on the lessons learned from the 2017 project in the production shaft. The service shaft project was scheduled to be completed in July, 2019. INTRODUCTION Nutrien Allan Potash is located approximated 75 km east of the city of Saskatoon, Saskatchewan, Canada. There are currently two shafts at Nutrien Allan Potash: the Production Shaft and the Service Shaft, transporting people and material from surface to a depth of 3,335 ft. The Production Shaft was completed in 1967, with one section of grey cast iron tubbing installed in the Blairmore formation between the 1605 and 2037 ft Levels. A second set of cast iron tubbing was installed in the Duperow formation between 2203 and 2463 ft Levels in 1999. The remainder of the concrete as of todays standards is designed as a pressure relief liner. The Service Shaft was completed in 1968, with one section of grey cast iron tubbing installed in the Blairmore formation between the 1600 and 2048 ft Levels. A second set of cast iron tubbing was installed in 1981, with 169 ft installed through the Duperow formation. The remainder of the concrete as of todays standards is designed as a pressure relief liner. PRODUCTION SHAFT REMEDIATION During the second quarter of 2015, the Mine Engineering team were notified of an area of concern in the production shaft. The shaft specialists of Golder Associates Ltd (Golder, formerly Alan Auld Canada) were contacted to complete an inspection of the production shaft liner with emphasis on the area of concern. Based on the inspection and documentation review, it was determined that the concrete at the 2804 foot elevation had been broken out for some time and was retained with #8 rebar bolts with resin encapsulation. The broken concrete was encroaching on the clearance to the conveyance."

Jan 1, 2019