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Shafts are the most important workings in the underground mines. Their technical state to a large extent determines the safety and efficiency of mining operations. However, in many cases periodically performed inspections show unsatisfactory technical state of the shaft lining (local defects, cracks, cavities, losses of the outer surface of the lining or, in case of the bricks, losses of the masonry). The most common cause of these types of damage is progressive deterioration of the lining material, impact of aggressive mine waters, impact of mining operations, deformation of the lining due to the rock mass saturation, seismic activity or periodic freezing of the lining in the upper part of a shaft. The paper presents legal requirements associated with the use of mine shafts in Polish coal mines as well as the ways and range of their control. Furthermore, examples of typical damage to shaft lining and ways to repair it, such as additional bolting, filling cavities or a wire mesh and shotcrete installation, are shown. In the final part, the paper presents a short example of a shaft, in which damage to the lining was one of the main causes of the shaft's failure. Due to the damage to the shaft lining, at the depth of approx. 65.0 m, the shaft was spontaneously filled with overburdened soil material. It resulted in a large crater to come to the surface, which, in turn, caused damage to the buildings and facilities present in the impact zone. On the surface the diameter of the crater was approx. 60.0 m, its depth approx. 11 m and the estimated volume was of about 30,000 m³. The disaster also caused disturbance in the ventilation of two neighbouring mines and the increase in methane hazard. Given the size of the crater, the measures to eliminate consequences of the catastrophe were undertaken in several stages.

Aug 1, 2013

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 M. Pötsch, A. Kluckner, P. Söllner, W. Schubert

"The in situ block size is a key parameter in the geomechanical characterization of rock masses. It describes the fracturing of the rock mass and thus is a measure for the degradation of the rock mass strength. Several classification systems use the in situ block size. For instance, the Geological Strength Index (GSI) requires the “blockiness” and joint surface condition factor as key input parameters. The “blockiness” has recently been related to the in situ block volume (Cai et al., 2004). Due to the limited information about the internals of a rock mass, it is not possible to determine the in situ block size directly. Currently, the in situ block size is determined by calculations using oversimplified models, vague estimations or, due to the lack of relevant information, it is neglected. As remote measurement systems have become available for rock mass characterization, a more comprehensive record of discontinuities can take place. Measurements can be performed on exposed rock outcrops and in particular on tunnel faces and walls, delivering the location, orientation, spacing and persistence of discontinuities at an arbitrary number and locations. An estimation of the in situ block size at the same level of sophistication is still not available. This paper aims at examining the relationship between visible and measureable information at the rock surface, and the in situ block size. Three-dimensional block model simulations were performed using the block model engine of the distinct element code 3DEC. Initial investigations focussed on the minimally required observation area in order to obtain reliable block size distributions. Based on a representative volume element, a reference distribution of the block area at the observation area for a specific discontinuity system was determined. Subsequently, the size of the observation area was decreased stepwise and each new distribution was compared to the reference distribution. For all analyzed systems, it turned out that the mean block area must be smaller than 1% of the observation area to achieve a reliable block size distribution. Further simulations focussed on discontinuity systems with three non-persistent sets. The results were compared to the formula proposed by Cai et al. (2004). A transformation factor T was introduced which replaces the persistence terms in Cai et al.’s proposed formula. The factor describes the correlation between block volumes generated by persistent and corresponding non-persistent discontinuity sets. The simulations included the variation of the discontinuity set spacing, persistence, and orientation. The mean and additionally the 25%-, 50%- and 75%-quantiles of the block size distribution were analyzed. Examining all values for the transformation factor the distribution can be described by a power function with a negative exponent. The function depends on the persistence only. Finally, the results of random simulations were compared to the analytical formula using the transformation factor. The predicted mean and selected quantiles show a good agreement with the simulation results. It gives a comprehensive picture about the block size distribution in discontinuity systems with three non-persistent sets."

Jan 1, 2015

By Kent Zehr

Suncor Energy Inc. is an integrated producer and refiner of oil and gas headquartered in Calgary, Alberta. The bulk of revenue comes from the Oil Sands Group (OSG) operating in the McMurray formation of the Athabasca Oil Sands. Located some 25 kilometers north of Fort McMurray, Suncor OSG began life in 1967 as Great Canadian Oil Sands, the first operator to successfully enter commercial production of synthetic crude oils from the area. For most of the last decade, dramatic growth has been the standard mode of operation for Suncor OSG. Production of synthetic crude first reached 100,000 barrels per day in 1997 and less than five years later is averaging in excess of 200,000 barrels per day. Within this dynamic organization, Suncor Extraction is the business unit that processes run-of-mine ore into clean diluted bitumen for Upgrader feedstock. Extraction also delivers and places the barren sand and process affected water into tailings storage in one of several ponds from which water is recycled to support the various processes. For reference purposes, Extraction on a typical day currently receives more than 400,000 metric tons of oilsand ore, which is all processed to water based slurry for separation in one of two extraction plants. Separated tailings are disposed of as a slurry and the cleaned bitumen froth is diluted with naphtha and sent to tankage for storage until required by the Upgrading Unit. As a consequence, on a typical day Suncor Extraction pumps more than 1,000,000 tonnes of aggressive slurry into and out of the two extraction plants.

May 1, 2003

By E. Cauda, K. Phillips

"Diesel particulate matter (DPM) exposures are a serious occupational health hazard in underground mines. While the complex nature of DPM makes direct analysis difficult, its primary component, elemental carbon (EC), can be used as surrogate. The near real-time FLIR Airtec monitor measures EC mass based on laser extinction. It was developed for use in underground metal/non-metal mines, and calibrated to the NIOSH Method 5040. Its effectiveness has not been demonstrated in coal mines, however, where coal-sourced EC could produce analytical interference. To gain preliminary insights regarding the Airtec’s performance in the presence of coal dust, experiments were conducted in a controlled laboratory chamber. The Airtec EC results consistently underestimated Method 5040 EC for both respirable-sized and submicron coal dusts. While underestimation of coal-sourced EC bodes well for limiting coal interference for DPM measurement, one key reason for the observed trend was non-uniform coal particle deposition on the Airtec filter. This may be problematic in coal mines where DPM and coal dust occur together in the instance that DPM deposition is also non-uniform. INTRODUCTION Diesel particulate matter (DPM) is an occupational health hazard, and underground miners have the potential for relatively high exposures due to their work in confined environments with large diesel equipment (NIOSH, 2011). DPM is heterogenous and complex in terms of its chemical composition (Birch & Cary, 1996; Noll et al., 2006), but elemental (EC) and total carbon (TC) are often used as analytical surrogates (Birch & Noll, 2004; Noll et al, 2015). EC is the solid “soot” component of DPM, whereas TC also includes particulate organic carbon (OC) (Noll et al., 2007). EC and OC can be measured in filter samples using the standard NIOSH Method 5040 (NIOSH, 2003), and summed to obtain TC. In US mines, TC has been adopted as the analytical surrogate for DPM in regulatory activities. In metal/non-metal mines, personal exposures are limited under 30 CFR Part 57. In coal mines, limitations are made on emissions from each piece of equipment (30 CFR Part 72) rather than for personal exposures. This is because coal dust has the potential to interfere with TC measurements in personal samples. In some other countries, and for non-regulatory purposes in the US, EC is also commonly used as a surrogate for DPM in mine monitoring applications [e.g., see AIOSH, 2013). EC generally exhibits a linear correlation with TC (Birch & Cary, 1996; Noll et al., 2006 and 2007) but unlike TC measurements, which are analytically intensive, EC can be determined more simply using a laser absorption/extinction principle on filter samples (Noll et al., 2013)."

Jan 1, 2019

Particles for heap leaching in conventional circuits are prepared using Cone crushers. Cone crushers are used to crush the ore to the size range between 12-25 mm for heap leaching operations. Leaching from these relatively coarse particles occurs only at the surface and in subsurface regions, which are accessible from the surface by cracks and pores. Since leaching is active in accessible areas, the method of comminution that forms multiple cracks and pores would offer an advantage for heap leach. An investigation was performed in this study to assess if the HPGR forms more cracks and pores than a Cone crusher. X-ray computed tomography (CT) was used to characterize the degree of cracks and pores formed by these two comminution devices that can be used for heap leaching feed preparation. In order to compare the effect of the comminution method on crack network generation, a bulk sample of the zinc ore was crushed by the HPGR at three different pressure settings (45, 95 and 120 bar), the sample ore was also crushed with a Cone crusher for comparison purposes. Products from the Cone crusher and HPGR experiment were then screened into five size fractions ((-25 +19), (-19+16), (-16+9.5), (-9.5+5), (-5+4.75) mm), Subsamples from the ((-25 +19), (-16+9.5), (-5+4.75) mm) size fractions were analysed. The spatial distribution of the crack network of sphalerite particles was characterized using a highresolution industrial X-ray CT system. This paper describes the use of image analysis techniques including image segmentation, which uses a combination of thresholding and other methods to characterize and quantify crack and mineral dissemination in the sphalerite particles after comminution with the HPGR and Cone crusher. The results are validated with those obtained using traditional techniques such as physical gas (with N2) adsorption, mercury intrusion porosimetry, SEM and QEMSCAN.

Jan 1, 2012

World copper electrowinning tankhouse plant practices have been surveyed. This survey is a supplement to previous surveys that have been carried out in 1995, 1999, 2001, 2002 and 2003. On a world basis, process technology trends include the further installation of automated electrode handling systems including permanent cathode systems, automated cathode handling machines, fully automatic cranes and polymer concrete cells. Designs also have included larger electrode sizes and higher electrolyte flows and current densities. Overall these trends have further resulted in optimized tank house productivities and improved electrowon cathode purity. Most greenfield copper electrowinning projects are occurring in South America and Central Africa.

Jan 1, 2007

By M. Moats

World copper refining tankhouse practices have been surveyed. This survey is a supplement to previous surveys that have been carried out in the 1987, 1991, 1995, 1999, 2001 and 2003. On a world basis, process technology trends include the further installation of automated electrode handling systems including permanent cathode systems, automatic anode preparation and cathode handling machines, section switches, fully automatic cranes and polymer concrete cells. General plant process control has increased with more automation of material handling in the copper refining tankhouse. The general trend for most greenfield copper refining projects remains in eastern Asia.

Jan 1, 2007

By Roger Lacroix

Fuel cell application to mining has been indicated to be potentially beneficial to underground mine worker health and to energy efficiency. In order to define the economic advantages of using hydrogen fuel cell vehicles, a detailed study of operating and capital costs associated with underground loaders and power supply infrastructure has been carried out. The results show that for a typical medium-size mine, operating costs and infrastructure costs are less for the fuel cell option versus diesel. The reverse occurs for capital costs owing to the currently higher cost of fuels cells versus diesel engines. This disparity is expected to decrease given the decline in price associated with fuel cell technology advances. Related market issues for fuel cell manufacturers are also presented. Despite the difference in cost, the resources and mine infrastructure required to operate loaders, and base design of the mine loader, is similar for diesel and fuel call versions.

May 1, 2007

By F. King, R. Sutherby, J. Been

With thousands of kilometers of buried oil and gas pipelines throughout the country, carrying flammable, high-energy hydrocarbons, the integrity and safety of this transportation and distribution network are paramount. The pipeline industry has the primary responsibility for pipeline safety and has in many ways taken the lead in dealing with safety issues. Over recent years, regulatory demands have increased, requiring operators to comprehensively evaluate their pipelines through indirect and direct inspections and to manage risk through integrity programs. Mechanistic and correlative models have been developed that assist in the prediction of pipeline integrity and the determination of reassessment intervals. These lifetime prediction models are based on decades of laboratory research as well as pipeline operating data, material data, and field monitoring data pertaining to soil conditions and CP. An overview is presented of an integrated approach towards the development of such models for the evaluation of external cracking and corrosion of transmission lines.

Jan 1, 2005

By Adrian White

Agenda Overview of pastefill at Kidd Mine Pipeline wear and the need to monitor Steel Loop monitoring Steel Borehole monitoring Monitoring pipe linings

May 1, 2013

By Alain Grenier

To be more competitive, we have to try new mining techniques. A few of them are: extend honghole length increase drilling precision new type of primary opening (slot) use of CMS to extend stope length This paper will cover our trials, successes and failures and will cover a few real cases that occurred at the Doyon mine.

Oct 1, 2001

By BARRY BANNATYNE

Non-swelling bentonite has been quarried in Manitoba by Pembina Mountain Clays Limited since 1941. It occurs in several thin layers near the base of the Pembina Member of the Upper Cretaceous Vermilion River Formation, and is quarried from the narrow outcrop belt along the slope of the Manitoba Escarpment. It is marketed both as natural and activated bentonite for a variety of specialized uses. Percolation of acidic water through bentonite has produced a naturally activated bentonite with good absorbent properties; these properties are enhanced by treatment with sulphuric acid to produce an activated bentonitefor decolourizing petroleum and vegetable oil.

Jan 1, 1984

By H. Vermette, J. Demers, R. Leclerc, P. Bergeron, P. Hudon, A. Lessard

The Arvida Smelter marked its 80th anniversary in 2006. Arvida currently operates 6 potrooms equipped with prebaked side-feeding pots producing 160 000t of aluminum per year, requiring the supply of 300 000t of alumina per year. In the past, to ensure reliable alumina supplies to the pots, especially in winter, a safety stock of alumina was kept inside the plant. The improved reliability of shipping on the Saguenay River has cut the need for such a stock. However, the stoppage of 8 Soderbergtechnology potrooms, starting in the 1980s up to 2003, generated alumina from the cleaning of pot pits, totaling 18000t and leading to the building-up of a significant alumina stock again. Concerns over working conditions, effect on potroom operations, and dust emissions prevented Arvida from tackling effectively this impressive alumina stock. Yet the increasing cost of alumina has created a strong motivation to use the stored alumina. In 2004 Arvida launched a project to recycle the stored alumina. This 4-year project aimed at clearing the alumina stock without affecting the operation of the smelter. It involved changing work organization, improving equipment and controlling the effect of the recycled alumina on the smelting process and working conditions.

Jan 1, 2006

By Ji Wang

Reflective in-seam wave detection has the advantages of a far detection range and wide applicability. It has been successfully used in detection of many abnormal geological structures in work-faces, such as faults and collapse columns. However, a reflective in-seam wave is a dispersion wave. It has weak energy and is always covered by the direct in-seam wave. In the past, underground seismic explorations were not able to image the opposite roadway using reflective in-seam waves. To solve this problem, we propose a new method of reflective in-seam wave imaging based on adaptive dispersion filtering. This method processes the reflective in-seam wave using a filter with the parameter of transmission distance. The degree of similarity of the filtered and the explosion signal is used to estimate the transmission distance and image the reflective objects. We test and verify this method using real underground seismic data. This research is helpful for the detection of coal mine goafs and abandoned roadways in work-faces or in front of tunneling ends.

Aug 1, 2013

By A. Dave Mackintosh

Historical closure data has provided a description of the stress distribution patterns occurring around mine openings and enabled the development of a time ? distance plot predicting the location of the stress peak and its migration away from mine openings with time. Data collected from active mining areas during the 1970?s and 1980?s indicated the peak appeared to stabilize approximately 135m (450 ft.) from openings after four years. The region of high load and accompanying poor ground conditions in which the peak was centred was spread over approximately 45m (150 ft.) to 60m (200 ft.). Recent data from new development headings cut adjacent to 25 year old extraction areas suggests load transfer takes place over a much greater distance and time frame than predicted.

May 1, 2001

By M Safa

Addressing deficiencies and defects that occur during construction projects is costly and time consuming. The manual quality assurance programs currently used in the industry have certain limitations, including human error and lack of consistency. Hence, there is a need for integrated electronic models that employ new technologies and methods. This research introduces an integrated construction quality control system that has the potential to improve quality management processes in the construction field for piping construction, which is a complex process often requiring rework. The proposed integrated system relies on data collected from construction sites using photogrammetry and laser scanning, which is then used to compare actual work performed to that designed. The proposed system aims to improve the promptness and accuracy of quality assurance processes, in particular dimension measurements, by avoiding human error and integrating defect detection and quality management. The use of this system has highlighted some of the limitations during data fusion and acquisition process, which are highlighted in this paper. These aspects must be considered to increase the reliability of the acquired information.

Aug 1, 2013

By Mike Robotham

Drum hoists in the 21st century have the same fundamental objective as their earliest 19th century counterpart. And yet a lot has changed in the design of the hoist from those early days of underground mining. These changes are driven by the need for greater productivity and reliability at ever increasing depths without compromising the all important safety demanded by the industry today. This paper reflects on how these changes have influenced design of a modern hoist Director of Engineering, Mike Robotham is a chartered engineer and has been with DavyMarkham for over 30 years. Having completed a craft apprenticeship he later joined the engineering department as a junior engineer. He has a wealth of experience of working on medium to large engineering projects in the field of mechanical, electrical and hydraulic equipment

May 1, 2013

By Jeonghwan Kim

Intelligent Excavation System (IES) has been considered to be one of the desirable solutions to improve the productivity, quality and safety of the current earthwork processes. IES is composed of various hardware and software modules including task planner (work command generator), local and global work environment sensors, GPS and other sensors to acquire the excavator?s status, robotic controller and electronic valves, and the manipulator (excavator). A data communication manager was required to coordinate the signal or data-flow in between these modules considering the operational status of IES such as; excavation start/completion, truck detection, terrain model update, emergency stop, local sensing, GPS/motion sensor data handling, and so on. This paper presents the role and functions of this data communication manager. After every possible operational status of IES operation was identified, a protocol of each communication process in the form of string-type was made. The components of IES are connected with either wired or wireless network. Therefore, they can communicate with the manager using socket (TCP/IP) communication. The data communication manager is also capable of accessing a web-based project management information system, which constantly updates the performance of excavation robot to online database.

Aug 1, 2013

By Mark Rantapaa

Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the Autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the Open Pit and Process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput. Better fragmentation and a subsequent increase in mill throughput were achieved through the use of: 1) Electronic caps for more precision and flexibility, as well as for allowing extremely fast shots. 2) Explosives with a higher velocity of detonation (VOD), to provide for improved shock energy. 3) Improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by six tph in 2003 due to the improved fragmentation of the hard ore. Barrick Goldstrike?s D2M initiative includes roaster ?hard ore? (BWI >17), as well as autoclave ?hard ore? (BWI >15). Approximately six million tons of D2M material is expected be shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs.

May 1, 2003