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The concept and practices of co-extraction of coal and methane have emerged in recent years to improve coal mining safety and productivity, utilise methane resources, and reduce fugitive emissions in environments that involve multiple coal seams with low gas permeability. The system of co-extraction integrates two previously separate operations of coal extraction and methane drainage. The coal mining operation reduces the coal seam gas pressure and creates strata fractures that enhance gas migration and capture from mine workings and surrounding coal seams. An effective methane drainage operation produces a consistent and quality clean energy product and, at the same time, reduces the methane concentration in underground workings and the methane content and pressure in the adjacent coal seams. This is a significant benefit in preventing gas explosions and outbursts, and promotes a safer and more productive coal mining environment. In addition, the co-extraction with enhanced utilisation of coal mine methane directly leads to a reduction in greenhouse gas emissions. Presented in this paper are key results and outcomes of a major Asia Pacific Partnership project carried out from 2008?2012 by the Commonwealth Scientific and Industrial Research Organisation in collaboration with Huainan Mining Industry (Group) Co. Ltd., to develop and demonstrate advanced technologies at Pansan mine, Huainan, that promote the concept and practices of co-extraction of coal and methane. A comprehensive approach was adopted to assess fundamental strata and coal seam methane conditions during mining, and optimise mining sequences and coal mine methane capture systems. The project has not only demonstrated a practical approach and procedures of advanced co-extraction of coal and methane systems but also delivered significant benefits and outcomes in improved mining safety and efficiency, increased methane capture and utilisation, and reduced fugitive methane emissions at the Pansan mine. The total mine gas drained increased from 25.36 Mm3 in 2007 to 47.0 Mm3 in 2011, and the mine gas utilisation increased from 4.94 Mm3 in 2007 to 21.15 Mm3 in 2011. The improved methane capture resulted in reduced coal and gas outburst risks and methane concentration levels at the mine workings, provided a safe working environment for coal production, boosted the mining efficiency, and eliminated methane related incidents over the last few years at Pansan mine.

Aug 1, 2013

By T. Kawai

Japan Oil, Gas and Metals National Corporation (JOGMEC) has started an exploration program for Seafloor Massive Sulfides (SMS) in the EEZ of Japan, and launched an investigation program for mining, processing and environmental impact on SMS development. With regard to the mining aspect, the mining system consists of three units: a mining unit on the sea floor, an ore lift-up unit to surface, and a mining support vessel unit which has an ore unloading system that unloads onto a shuttle ship. Regarding the mining unit, JOGMEC and certain Japanese mining and machinery companies developed two types of state of the art mining testing tools. Excavation tests on the actual SMS site in the Okinawa Trough, south-west of Japan, were conducted in 2012. In these tests, the functions of the testing tools, such as cutting ore, moving on the seafloor and climbing up slopes having steeper than a 25 degree gradient, were confirmed. The physical characteristics of the ore, which are key parameters for establishing a mining system, are yet to be fully understood as the exploration program has been undertaken simultaneously. Hence, those examinations have been carried out by ground cutting experiments, analysis of drilling core data, and the like. This paper describes the outline of a proposed mining system, mining testing tools and results of the on-site mining testing.

Aug 1, 2013

By D. Ofstie, B. Kargutkar

BIM, or Building Information Modeling, is transforming the way metallurgical facilities are built, operated and maintained. BIM provides a digital representation of the facility, complete with all physical and functional characteristics - enabling collaborative planning, concurrent design, construction simulation, sustainable operations and predictive maintenance through a connected information model. Building on experience gained in other industries, Hatch is aggressively applying the BIM process to the mining & minerals processing industry to address inefficiencies inherent in traditional document-based information management. Intelligent 3D models support real-time quantity forecasting and cost trending by commodity type and construction work package. By linking procurement and schedule data, material availability and constructability reviews are visualized to verify construction critical path, ensure work front safety and minimize craft downtime. The BIM digital information model connects engineering, construction, commissioning and vendor data, aiding timely asset-centric handover to plant operating and maintenance systems.

Jan 1, 2015

By J. Kolacz

"A new sensor based sorting system has been developed, providing a possibility for laboratory scale testing and further scale-up of the separation results to the industrial operation. The new system contains different sensors as: X-ray detectors, visible light cameras, NIR cameras, ultraviolet cameras and magnetic sensors, in the same sorting unit. The sorting unit allows advanced calibration options and fine-tuning of the installed sensors to achieve the best separation effect under controlled conditions. Finally, the processed material can be analysed and separated by the rejection mechanism, similarly to the industrial scale operation. At the same time, the process is carried out with limited amount of material allowing detailed statistical calculations for processed particles and all sensor types. The optimal settings and sensor types are specified for the industrial application.The paper describes the scale up of the results achieved for iron ore and coal, where the test work was first carried out using the new laboratory sorting system and where the industrial scale sorting system has been built, in the final stage. The industrial scale sorting results showed a very good correlation between the laboratory and full scale operation. Thanks to the detailed study carried out in the laboratory equipment, the settings of the sensors in the full scale operation provided much better separation efficiency. It was especially important to provide proper setting for the X-ray sensor data calculations, which can be very critical for achieving the best results. During the industrial scale sorting of coal, the input material had 40-55% rock particles as the direct source of ash in the coal stream. The optimal laboratory unit settings and transferring these settings to the industrial sorter, provided 98.8% efficiency for removing rock particles with only few % losses of coal."

Jan 1, 2016

By Shinji Muraishi, Shinji Kumai, Yasutaka Kedo, Takashi Kambe

"Magnetic pulse forming (MPF) is one of the extreme high-speed forming processes. A metal sheet which is accelerated by electromagnetic force is collided onto a mold and fine and sharp details of the product can be obtained. The deformation mechanism of the MPFed metal cannot be understood only by the microstructure observation of the deformed metal. The deformation behavior of the metal should be investigated also by considering the local microstructure change with strain, strain rate and temperature change during deformation. Numerical analysis is an effective method to achieve this requirement. In this study, pure Al and Cu sheets were deformed by MPF. Impact velocity of the metal sheet was calculated by using ANSYS Emag-Mechanical. Based on the obtained impact velocity, the deformation behavior of the metal sheet was reproduced, and local strain, strain rate, and temperature were analyzed by using ANSYS AUTODYN. The relationship between the local microstructure change of Al and Cu sheets and the deformation parameters was examined.INTRODUCTIONMagnetic pulse forming (MPF) is one of the high-speed forming processes using electromagnetic force. Fine and sharp details of the product can be obtained, and springback after deformation is extremely reduced in comparison to the conventional forming processes(Psyk, Risch, Kinsey, Tekkaya, & Kleiner, 2011). Figure 1 shows a schematic diagram of MPF. A metal sheet is placed over the coil in the discharge circuit. The discharge current runs through the coil, and magnetic fieldis producedaround the coil. An eddy current is inducedin the metal sheet. Interaction between magnetic field and eddy current creates electromagnetic force. The metal sheet accelerated by electromagnetic forcecollides ontothe mold. Forming is completed in a few tens of micro-seconds.MPF is suitable for metals with a high electrical conductivity like Al and Cu.The MPFed metal may have characteristic microstructure because of high strain rate deformation."

Jan 1, 2018

By Bryon Cerklefskie, Michael Schulte

"This case study explores the usage of polymer ducting as a replacement to curtains and FRP for face ventilation in two coal mines. There are two mines looked at, one is the highest elevation underground coal mine in North America, the other is the gassiest mine in North America. The paper details the trials of both mines switching from FRP and curtain respectively to polymer ducting. The results discuss the ability for the mines to not only achieve consistent airflows and keep them in compliance but the unexpected positives. Mine A was allowed to do longer cross cuts due to increased air volume at the face. This drastically cut their costs of mining down due solely to modification of the ventilation cycle. Mine B saw economic benefits due to longer cuts between place changes. Both mines have documented lower dust, methane, noise, and improved wear and tear on their equipment as a result.INTRODUCTIONThe emergence of longwall mining in underground coal operations has resulted in new ventilation challenges. Numerous production crews strive to complete their development sections with enough time to adequately prepare for the upcoming longwall panel. Continuous miners will cut out two or three entry development sections per their ventilation plan, that is approved and controlled by MSHA (Mine Safety and Health Administration), which will drive amount of footage that can be mined at a time prior to installing roof support. At this moment the continuous miner, hereafter referred to as the CM, will back out of the entry and moves to the second entry to complete a similar cut. Typically, a roof bolter crew will pull in to the finished cut section and install ground support. This is called a place change style of production coal mining. There is an alternate method that includes a miner/bolter combination as well but that was not featured at either test site in this case study. Ventilation has to be provided to sweep the working face of each entry to control dust and gasses. Each task will have an MSHA prescribed ventilation requirement dependent on the dust levels and methane emissions of the rock for that particular mine. The CM, roof bolting and unused headings will each require constant ventilation but at different volumes. Since each working face is changing throughout the mining cycle the ventilation requirement in a working heading is never static and is changing with the working task.Traditional Ventilation ControlsTraditionally face ventilation for coal mining operations has been completed thru the usage of a curtain system and\or using auxiliary fans and ventilation tubing. Room and pillar mining systems typically utilize curtain systems, which use curtain walls that are installed by the miners by erecting wood framing and covering it with brattice curtain. This splits the drift width to allow fresh air to sweep the face and take the contaminated air and dust behind the curtain to the ventilation exhaust\return area of the mine. This method is difficult to adjust the airflow from entry to entry during changing cycles and requires that a wider drift is mined out in order to have enough room for the brattice wall. In operations that require roof bolting, this method limits the length of the cuts from the CM prior to advancing and can lead to not providing enough ventilation to keep dust and methane levels below compliance requirements."

Jan 1, 2019

By G. Q. Zhou, H. C. Liang, X. D. Zhao

"This study describes the strain behavior in vertical shaft lining (VSL) embedded in thick soil deposits and its application in assessment of concrete deterioration. The observed strain in VSL continuously decreased companied by a sinusoidal fluctuation due to the influences derived from negative skin friction (NSF) and temperature. The increase in strain increment between peak and trough at each year and compressive strain level as the servicing time continued and VSL depth increased implies that the concrete strength was attenuated, and this attenuation was significantly dependent on the existing compressive strain level in VSL. The reliability of the proposed approach was validated by Schmidt Hammer Technique (SHT) – based concrete strength, and is applicable in concrete assessment and then fracturing prediction of VLSs in thick soil deposits.Concrete strength, Field monitoring, Strain behavior, Vertical shaft liningINTRODUCTIONOver 100 VSLs in Southeastern China subjected to an unpredictable fracturing as shown in Figure1, and there are over 1,000 VSLs embedded in thick alluvium su?ering from challenges of damaging and potential fracturing (Cheng, Yang, Zhou, Li, & Hu, 1993; Zhou, Cui, Lv, Huang, & Chen, 1999; Li & Li,2005). Therefore, a reliable assessment of these VSLs is significant to the normal servicing of mine shafts and the recycle of underground space when these mine shafts were closed.The continuous increasing of NSF induced by the drainage of water–saturated deposits well interpreted such extensive fracturing phenomenon, and it is universally regarded as the governing indicator to determine the VSL stabilization (Cheng et al., 1993; Zhou et al., 1999). Based on this recognition, the fracturing prediction and VSL strengthening according to the field monitoring on hydrogeological characteristics, servicing environments, and mechanical behaviors of VSL were carried out (Zhao, Zhou, Zhong, Zhu, & Liang, 2009; Liang et al., 2009; Xie, Lv, & Wu, 2014). As known, the compressive strain level in VSL and the in–situ strength of VSL concrete were the main factors to perform such fracturing prediction. However, the existing studies in literatures were limited to the strain accumulating or releasing behaviors (Zhao, Zhou, Zhao, Kuang, & Hu, 2017), and lack of considering the VSL concrete strength and its attenuation. In this reported study, the in–situ monitoring data on the strain in typical VSLs and the VSL elevations between 2004 and 2014 were initially analyzed. Then, an observed strain behaviors–based approach was developed to quantitatively evaluate the VSL concrete deterioration."

Jan 1, 2019

By Dwayne D. Tannant

This paper presents a new mining concept for oil sands called ?hydraulic underground mining of oil sands? or HUMOS. While this mining method is still at the conceptual stage it has great promise to allow extraction of bitumen from areas that are currently uneconomical or technically infeasible using surface mining or steam assisted gravity drainage. HUMOS is founded on a combination of recently proven technologies such as directional drilling, water jet cutting of oil sands, slurry transportation, cold water extraction of bitumen, and thickened tailings. One key component in the mining concept is the caving of oil sands and the creation of an underground cavern. Scaled-down physical models will be designed and built to demonstrate water jet cutting, cave development, and insitu primary bitumen separation. These will be used as a 'proof of concept'. On-going research will establish and prioritize issues that need to be resolved, outline key areas where further research is needed, foster establishment of research teams to divide and conquer the important questions, and create framework for future coordinated research efforts.

May 1, 2001

By K. Soucek, J. Ptácek, A. Hastíková, R. Kukutsch, P. Konícek, P. Waclawik

"Cable bolts are used frequently as a secondary support system (with steel arch support) in difficult stress-strain conditions of deep coal mines. The load transfer mechanism of cable bolts depends on several factors, such as the strength, deformation and geometric properties of the bolts, resin and the surrounding rock mass so-called cable-resin-rock system (CRR system). The bonding length and bolt/borehole diameter ratio strongly influence the final bearing capacity of the CRR system.The study presents the behaviour of CRR system during a pull-out test which is usually used in the carboniferous rock mass in the Czech part of the Upper Silesian Coal Basin. A series of 28 pull out tests were performed on 3-m-long cable bolts, with various combinations of borehole diameters and bonding lengths, to understand this behaviour. Boreholes were drilled into a solid rock mass consisting of fine-grained sandstone to guarantee similar conditions during the pull-out tests. Video inspection and measurement of borehole diameters were performed to determine their quality and real diameters. Three characteristics were observed from pull-out test results: ultimate pull-out load; displacement of the end of bolt and system stiffness. Numerical modelling by FEM (Finite Element Method) was used to determine the stiffness of the CRR system for variable bolt/borehole ratios and bonding lengths each under constant load. A linear elasto-plastic model and a mohr-coulomb model were used for cable and resin-rock respectively. The results of the experiment may contribute significantly to improving of the methodology of cable bolts installation as well as the design of used cable bolts."

Jan 1, 2015

By John T. Ling

"This paper describes the operation of a rope haulage used as the main system of transportation in an underground coal mine. Prince Colliery, which is operated by the Cape Breton Development Corporation, has been in operation for 23 years and produces 1.2 million tonnes of coal annually. The mine extends a distance of 8000 metres under the Atlantic Ocean. All personnel and supplies are transported by means of an endless rope haulage system consisting of a train of rail cars that are operated by an electric engine on surface. The wire rope is 15 km long and weighs 63 tonnes. The system is believed to be the longest of its type used in an underground coal mine. The design of the system, safety features of the haulage, and problems encountered during the design and construction are described. IntroductionCoal has been mined commercially in Cape Breton, Nova Scotia since the 1800s. Several coal seams that are part of the Sydney coal fields, dip toward the north and northeast out under the Atlantic Ocean at angles between -4 and -15 degrees. Coal has been economically mined at depth in excess of 1200 m and more than 11 km from the coastline.Traditionally, single and double drum hoists have been used to haul the coal to the surface and also for transporting the workers and the materials required for mining up to 8 km. With the introduction of mechanized mining methods in the late 1960s, conveyor belts began to replace rope hoists for coal transportation. Improvements in hoisting system design also allowed for drums that could wind up to 6100 m of 32 mm wire rope in 15 layers.These hoists are commonly referred to as “drop hoists” because they take advantage of the gradient of the slope to assist in allowing the mine car train to reach the end of travel. The cars travel on steel rails and the rope is guided by rollers to reduce friction in the system."

Jan 1, 1999

By A. Belleau, F. Lavoie

"Quebec Iron Ore Limited (QIO), a subsidiary of Champion Iron Limited (Champion), secured assets in early 2016 from the previous Bloom Lake operations in the heart of the Labrador Trough region of Northern Quebec, Canada. A plan was developed to bring the Bloom Lake facility back in operation once the iron ore market conditions improved. The project restart involved several aggressive moves to change operational effectiveness, one of which was the utilization of the existing Phase 1 Plant with an upgraded process flowsheet and equipment. The production target was 7.4 million tonnes per annum of 66% iron ore concentrate with an approximate 10% increase in iron ore recovery. The Phase 1 upgraded flowsheet was initially based on review of historical Phase 1 data and pilot testing data undertaken during the original Phase 1 operation and was finalized once additional metallurgical test work and process modeling was carried out by Mineral Technologies in late 2016. The final upgraded flowsheet is comprised of rougher spirals, rougher middling scavenging spirals, and an up-current classifier (UCC) with overflow scavenging spiral stage. A portion of the gravity circuit tailings treated by a series of wet high intensity magnetic separators (WHIMS) to boost overall iron recovery. This paper will describe the efforts taken to test and design the Bloom Lake Phase 1 upgraded flowsheet and report on the plant performance since commissioning in first quarter of 2018.SITE HISTORY The Bloom Lake iron mine property is located approximately 13 km north of Fermont, Quebec, and 10 km north of the Mont Wright iron ore mining complex, property of ArcelorMittal Mines Canada. The Bloom Lake mine facilities include a 32 km railway to efficiently transport the high-quality iron concentrate to a loading port located in Sept-Iles, Quebec. The Bloom Lake property was first explored in 1951 and went through multiple minor exploration campaigns by different companies up until 1998. A major exploration program was conducted by Quebec Cartier Mining (QCM) in 1998. This program included line cutting, surveying, diamond drilling, geological mapping, mini-bulk sampling, bench-scale preliminary metallurgical test work and preparation of a “mineral resource” estimate."

Jan 1, 2019

"Real-time, on-stream analysis of the metal content of process slurries is an essential prerequisite for process monitoring and advanced control of mineral processing circuits. On-stream X-Ray Fluorescence (XRF) sensors for base metal applications are available commercially and form the basis of many plant monitoring circuits. To date, these commercial technologies have been insufficiently sensitive to measure precious metals such as gold and platinum group elements, typically present at part-per-million (ppm) and sub ppm levels. CSIRO has developed a novel X-ray based technology, called UltraGold, which enables detection of gold in slurries on a real-time basis with a precision below 100 parts-per-billion. This technology is based on the use of advanced X-ray optics, extensive Monte Carlo computer modelling for analyser design, high accuracy X-ray spectrum fitting where the X-ray intensities are matrix corrected. In this paper, we will introduce this technology and discuss the results of a proof of principle study performed in the laboratory with plant slurries (tailings and concentrate) from an Australian beneficiation plant. Finally, we will discuss further planned improvements. As projected grades in (gold) mining around the world fall and several large-scale mines approach the limits of their economic reserves, this method can enable significantly reduced operating costs by rapid analysis to improve circuit efficiency and hence improve recovery significantly.INTRODUCTION This paper describes a study undertaken to explore the feasibility of applying CSIRO?s UltraGold XRF technology to the on-stream measurement of gold in process slurries. The provision of rapid, accurate information of gold grade in feed, tailings and concentrate streams would facilitate significantly improved process control and early detection of plant upsets, resulting in substantial cost-savings. CSIRO have patented X-ray fluorescence (XRF) techniques for the analysis of key elements in slurries present at part-per-million (ppm) and sub-ppm levels. Conventional, commercially available on-stream XRF instruments generally have detection limits in the tens of ppm range, precluding their use for analysis of elements like gold that are mined and processed at much lower concentrations."

Jan 1, 2017

By K. E. Waters, E. R. L. Espiritu, G. R. da Silva

"Rare earth (RE) elements are essential components of emerging green technologies. The increase in demand for these applications have driven the search and development of new rare earth deposits such as the Niobec project in Quebec, Canada. This deposit consists primarily of dolomite with significant amount of RE minerals bastnäsite and monazite, the primary sources of RE elements. Due to the minerals’ fine liberation sizes, flotation is commonly used as a concentration method. To develop an efficient process, the electrokinetic properties of the minerals must be understood. In this study, the surface properties of bastnäsite, monazite (RE minerals) and dolomite (a common gangue mineral) were investigated by zeta potential measurements. These measurements are affected by various ions present in solution; for bastnäsite, monazite and dolomite, some of these ions are H+, OH-, PO43- and CO32-. Dolomite, being a sparingly soluble mineral and a primary component of the ore, may be the greatest contributor of these ions in solution in the form of CO32- ions. Thus, different sources of CO32- ions (from dolomite dissolution and from Na2CO3) were investigated. The research work aims at elucidating how these reagents may influence the minerals’ surfaces. The results have shown that dolomite supernatant and sodium carbonate greatly affect the electrokinetic properties of each minerals. The addition of dolomite supernatant have resulted to relatively similar zeta potential of the minerals; while, sodium carbonate have affected them differently. These observations could be useful in efficient flotation of bastnäsite and/or monazite from bastnäsite-monazite-dolomite system.INTRODUCTIONThe increase in the demand for rare earth (RE) elements has driven the search and development of new deposits. Out of 53 rare earth projects in the world, 19 can be found in Canada (Hatch, 2015). These include the Niobec project of Magris Resources Company in Quebec. This deposit contains a significant amount of rare earth minerals (such as bastnäsite and monazite), with carbonates (such as dolomite) as the primary gangue minerals."

Jan 1, 2016

By M. R. MacIver, M. P. Pawlik

"An image analysis method based on chord length distributions is applied to the batch settling of polyacrylamide flocculated kaolin suspensions. Two features of the interaggregate void space, the void chord length distribution mean and the white-to-black distribution ratio are extracted from an image series obtained over the two hour settling experiments. This approach produces three signal values, from two different probability distributions that can be measured as an indication of underlying sediment bed density and aggregation state. Further work is required on the physical interpretation of the signal, the image acquisition conditions, and the parameter selection methods. It is suggested that this chord length based feature extraction technique may be a useful signal to monitor during batch settling or thickening.INTRODUCTIONFew in situ techniques are available that can be used to directly measure aggregate properties within sediment beds in thickeners or secondary settlers. Typical process variables monitored include rake torque and height, bed level and pressure, feed rate and density, underflow rate and density, settling rate, and overflow turbidity; yet these process variables are only weakly related to process dynamics (Concha et al. 2014). Additional process monitoring signals, based on the direct measurement of aggregate properties could improve solid-liquid separation control and allow the extraction of more detailed information from batch settling experiments.Several optical methods exist for measurement of moving suspensions of aggregated solids in the dilute concentration regime, such as focused beam reflectance measurement (Peng and Williams 1994), and the turbidity fluctuation method (Gregory 1985). In the more concentrated region of a thickener, acoustic backscatter penetration and attenuation measured with an acoustic probe and changes in the underlying solid concentration in the highly concentrated, near-bed region of a thickener as a function of height and time (Hunter et al. 2012). While machine vision for froth monitoring has been thoroughly studied with at least five commercialized technologies (Aldrich et al. 2010), its’ application to the study of thickening has been limited."

Jan 1, 2016

By Kazem Oraee

Implementing stable final pit walls in open pit mines during the open pit design phase and mine exploitation has become one of the most important concerns of mining engineers in recent years. Failure of mine walls can potentially cause loss of life, roads blocks, and damage to mining machinery, temporarily or permanently halt production at the face and in the worst case scenario, close the mine. Thus, the role of creating stable mine walls is crucial to safety and general operations of mines and any effort to optimize this process has great economic value for mine operators. This paper aims to illustrate the technical aspects of use of the successful presplit blasting method in metal open pit mines. It also shows that using this approach not only increases safety in mines through wall stabilization, but also will boost economic profits by savings in stripping ratio. In this regard, appropriate practical concepts for designing the drilling and blasting patterns and the role of selecting the correct drilling rigs are elaborated in detail through conducting a case study in Chador Malu iron ore mine in Iran.

Aug 1, 2013

By F. P. Hassani, A. Hara, M. Momayez

To be competitive on the international market, the Canadian mining industry must reduce its costs, increase its productivity and maintain a high standard of safety. There is a great need today for improved methods that would allow the detection of geological structures in advance of mining to reduce dilution and the monitoring of underground structures to increase safety. This will facilitate planning for optimum exploitation of the mine and to increase production at lower costs. This paper discusses two examples of more efficient mine planning using new technologies such as Ground Probing Radar (GPR). In Kidd Creek mine, GPR technology was used at the 2500and 2600 levels to (1) monitor the stability of the sill pillar; (2) locate the presence of disseminated sulphide pockets in the sill pillar for extracting the mineral content; (3) monitor the stope backs and wall structures to evaluate the effect of on-time filling sequences; and (4)assess rockfill quality in terms of the presence of voids and fractures within the rockfilled areas. In the New Brunswick coal mine in Minto, GPR was used along with core log data to map and construct a 3D block of a section of the bench showing the relative position of different layers overlying the coal seam.

Jan 1, 1996

By Adrian Dance

Newmont Mining Corporation?s Carlin (?Carlin?) operation processes roaster feed through a double rotator, dry grinding mill following secondary crushing. Metso Process Technology & Innovation (?PTI?) was involved in a review of crushing and dry grinding circuit operations in August 2009. A number of opportunities for increased throughput were identified in the PTI study. Extended plant trials were conducted in July 2010 to provide justification for possible circuit modifications and if needed, additional equipment. The trials confirmed that a finer crusher product would reduce the build-up of material ahead of the coarse grinding chamber in the double-rotator. Also revealed were material transport and airflow restrictions in the dry grinding circuit that resulted in a high circulating load. The secondary crushing plant demonstrated it was capable of reducing the amount of +¾? material in the mill feed thus increasing dry grinding throughput. However, wet and sticky feed affected screening efficiency resulting in low utilisation of the existing crusher capacity. The open circuit configuration also made it difficult to control crushing circuit product size. For the dry grinding circuit, changes in grinding media size, transfer grate design and increased airflow were recommended to reduce circulating load issues and increase circuit capacity. This paper summarises the crushing and grinding circuit review, the extended site trials performed by PTI and the improvements in dry grinding operation that resulted from this study.

Jan 1, 2012

By Parviz N. Farsangi, Ferri P. Hassani, Allen G. Hayward

"Kidd Creek Mines places approximately 10 000 tonnes of consolidated rockfill (CRF) daily. Consolidated rockfill comprises sized aggregate mixed with different ratios and amounts of binders. Consolidated rockfill is employed to simplify subsequent pillar recovery and provide improved passive/active ground support.The consolidated rockfill is designed to sustain not only the gravitational loading of the overlaying fill material, but also to some extent the dynamic loading applied during blasting of the adjacent stopes and/or pillars. This paper describes the steps taken to optimize the pre-sent fill system at Kidd Creek Mines.The emphasis is on four areas which have high saving potential: lower cost alternative binders, structural design, quality control measures, in-situ testing techniques for back analysis. A consolidated rockfill design optimization chart was developed from these investigations."

Jan 1, 1996

By V. Falmagne

The mining sequence at Noranda?s Bell-Allard mine calls for two mining fronts retreating toward a central pillar known as the Retreat Zone between pyramids A and C. It is clear from numerical modelling and rock mass characterization that the induced stress level in the pillar will exceed the rock mass capacity. A mining plan was developed including the re-dimensioning of stopes in the Retreat Zone, additional ground support and instrumentation in order to ensure the safety of the workforce and to maximize ore recovery while minimizing production delays. The mining strategy consists in allowing the rock mass to fracture and fail progressively while maintaining control of the existing openings with the appropriate support. A systematic analysis of rockbursting and caving hazards was conducted for all accesses and stopes in order to plan ground support and instrumentation needs.

Apr 1, 2004

By Patrick Rennkamp, Wolf-Dieter Trodel, Andy Fearn

"The Jansen shafts are completed using purely mechanical excavation. This paper summarises the geology, a description of the shafts, the method used for excavation and the results achieved along with the challenges encountered and the solutions developed during the project. This experience is now being applied in the next generation machines and shaft sinking processes. This pioneering approach is changing shaft sinking in soft and medium to hard rock. INTRODUCTION The Jansen Mining project located approximately 150 km east of the city Saskatoon is the location of the BHP owned potash mine with an expected mining output of eight million tonnes annually upon completion. Mining contractors DMC Mining Services have used two Herrenknecht Shaft Boring Roadheaders (SBRs) to excavate the two blind shafts with an approximate excavation diameter of ten metres (inner diameter approximately 8.3 m) to depths of -975 and -1005 metres, respectively. The SBRs excavate the rock by a partial-face cutting method, using a transverse cutting drum mounted on a telescopic boom. The excavated rock is then conveyed away from the bench by an innovative pneumatic system and transferred into muck buckets to be hoisted to the surface. No drilling and blasting was done to keep to the BHP philosophy of using only mechanical excavation for this reference project. BHP VISION – MECHANICAL EXCAVATION BHP focused on mechanical excavation at Jansen due to the following perceived benefits: 1.No workers in the excavation chamber (shaft bottom), minimizing the exposure to traditional shaftsinking hazards associated with working in the shaft bottom. 2. Minimal damage to the rock fabric reducing the need for ground support and avoiding potential impact damage to freeze tubes located around the shaft. 3. Accurate excavation diameters with no overbreak, reducing volumes of rock to be removed and replaced with concrete lining."

Jan 1, 2019