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By Sakai Kunito, Nigel B. Sugden

If an Earth Pressure Balance (EPB) TBM is operated effectively tunneling can be carried out producing negligible ground movements. Using the methods given in this paper face losses of the order of 0.5% and less are generally obtainable using an EPB. Operating the EPB TBM in this manner reduces the requirement for the building protection measures used to protect surface structures. This can result in a considerable cost saving for the construction of a tunnel under built up areas. This paper to give guidance on the causes of ground movements around a TBM and the methods of running an EPB TBM that will minimize those movements. Details of how this was successfully done during the construction of the Bangkok Metro are given. The paper is split into three parts as below. 1.Causes of ground movements due to TBM tunneling 2.Methods of controlling those movements using an EPB TBM 3.Case history Bangkok Metro (water main)

Jan 1, 2001

By M. Fustic, A. H. Paul

The geology of the Muskeg River Oil Sands Mine is described to demonstrate how geologic modeling aided in resource evaluation and material characterization during the feasibility and construction stages. Bitumen is hosted in the clastic sediments of the Cretaceous McMurray Formation which is informally divided into members representing the fluvial, estuarine and marine environments of this transgressive sequence. Lithofacies mapping of drill core provides further detail to classify materials as resource type, for extraction suitability and for construction suitability. Geologic interpretation provides tools for the engineers to produce effective mine plans and for the operators to execute them during mine development.

Jan 1, 2002

By B. J. Arnold, N. Terblanche

The features of the ‘Turbo’ froth flotation column will be discussed, including the double aeration system that improves flotation yield while not sacrificing grade, the internal launder system, and the unique feed/tailings sump that evens out flow to the flotation column preventing upset conditions. Results from various test programs and installations will be presented.

Jan 1, 2001

By Takuji Yamamoto

High-speed TBM excavation requires rapid ground assessment ahead of excavation, particularly in complex grounds. The Tunnel Reflector Tracing technology (TRT) developed by authors, uses seismic reflections to produce volumetric images of ground anomalies. To further minimize interruption in the TBM excavation the authors modified surveying technique switching from cable (wired) to radio (wireless) data acquisition system. This paper presents the outline of the Wireless TRT system, and compares the results for the wired and the wireless surveys. The comparison shows that the wireless system offers high precision data, is more efficient and economical and significantly less intrusive in tunneling operations.

Introduction Aggregate mining impacts on water resources are a source of concern to local governments. To evaluate those impacts, the Minnesota Department of Natural Resources conducted a four-year study at three gravel pits (two alluvial and one beach-ridge) and five quarries (flat-lying Paleozoic limestone). This research provides the first comprehensive look at aggregate mining impacts on ground-water systems in Minnesota. The results will be used by government officials making permitting decisions about aggregate operations and by responsible owners of aggregate mines as they plan their operations to avoid conflicts with neighbors and with resources dependent on ground water and surface water. Natural aggregate (crushed stone, sand, and gravel) is a vital part of our economic infrastructure in Minnesota. Aggregate is used for road and bridge construction and in a variety of building materials. In 2003, the value of construction sand and gravel and crushed stone in Minnesota was approximately $245,000,000. As Minnesota’s economy continues to expand, the demand for aggregate will continue to grow. Sand and gravel pits are located in every county in Minnesota. In 1990, the Minnesota Department of Natural Resources, Division of Minerals (DNR Minerals), estimated the number of active and inactive operations at 1500 with the view that this number was likely too low. Quarries for mining limestone, dolomite, sandstone, and hard rock (granite and quartzite) are found in 34 counties. A 1990 DNR Minerals inventory found 165 active operations, 88 percent of which were limestone quarries (Nelson and others, 1990). That same inventory counted 1,367 inactive operations, 70 percent of which were limestone quarries. Aggregate mining is an extractive use of resources: mining alters the landscape and its natural hydrologic system. When a new pit or quarry is proposed or when an existing operation needs to expand, local governments and citizens typically have many questions about the impacts mining might have. Local governments, which are responsible for reviewing these operations, rarely have the budgets to hire experts to evaluate potential impacts of quarry and gravel pit proposals. The Minnesota Legislature’s Aggregate Resources Task Force identified that local government units (LGUs) often lack the expertise to assess ground-water models (Southwick and others, 2000).

Jan 1, 2007

Analysing a flotation plant?s operating performance requires accurate metallurgical sampling. Typically, the aims of performing flotation plant surveys are to establish a consistent and accurate understanding of the operation of the circuit as well as to identify potential areas for improvement. Once the data have been collected, a mass balance is required to provide a consistent set of data from which plant performance can be assessed. Mass balancing is a key skill that many metallurgists and mining industry professionals are familiar with. Mass balancing reconciles the feed and product streams throughout the plant and is sometimes used for accounting of the material entering and leaving a system (eg. JKMetAccount). However more common reasons for mass balancing are: better understanding of the flowrates within a system, assessing the quality of data obtained from sampling and surveys, and providing a key dataset for assessing and improving the performance of unit operations. Mass balancing requires practice and experience to determine if the results are reasonable. There are various software programs available to assist in the mass balancing and understanding of processing plants. This paper is focused on JKMultiBal initially developed by Gay (1993), and then later commercialized by JKTech. JKMultiBal in its current release is for balancing data in both one and two dimensions, i.e. balancing data on either sized or assay bases as well as size-by-assay. With the recent trend in flotation circuits becoming more complex, JKMultiBal has been used to gain a better understanding of the processes occurring within the circuit. This paper provides a description of the program as well as several case studies where the two-dimensional mass balancing has resulted in improvements in plant performance.

Jan 1, 2009

By C. Bucknam, M. McComb

Mercury and silver polythiocarbonate sludge that was generated from the pilot testing of optimized mercury removal from cyanidation pregnant eluate solutions prior to Merrill-Crowe recovery of gold and silver were tested for long term stability at Newmont Metallurgical Services. Sludge samples were mixed with heap leach residue to simulate disposal of the sludge in spent or active areas of the heaps and leached for twenty weeks with water and cyanide leaching solution, respectively. Leach testing results are presented as well as analysis of the sludge using scanning electron microscope techniques down to the <1000 nanometer scale.

Jan 1, 2007

By E. Farrokh

Estimation of the cutter life and cost is a part of evaluating performance for a hard rock TBM in any project. Various approaches has been proposed for calculation of disc cutter life in various rock types based on machine specifications and rock strength and abrasivity. Cutter change time is a parameter that is used in some of the estimates and is defined as the average time required for changing a cutter on the cutter head and cutter life is the number of cubic meters of excavated rock per each disc cutter. Analysis of cutter life information of several tunnel projects from around the world has revealed that the published models for estimation of cutter consumption require some revisions to offer a more accurate prediction. The preliminary analysis of data shows that the average cutter change time is approximately 66 minutes for different cutter sizes and there is a minimal difference between corresponding cutter change times of the large (e.g. 19 or 20 in) versus smaller cutters (e.g. 15.5 to 17 in). This paper reviews the available and published cutter life data from various projects. It also introduces new models for estimation of cutter life and cutter change time as part of TBM down time and utilization analysis.

Feb 27, 2013

Column flotation has been successfully implemented on a production scale in the Athabasca oil sands. In this application, bitumen is recovered and mineral matter is simultaneously rejected from a middling stream originating from a primary separation vessel. Exploiting the natural hydrophobicity of bitumen, the middlings streams have traditionally been processed utilizing conventional, mechanical flotation cells. Although these cells offer adequate bitumen recovery and mineral rejection rates, operating costs are high due to the required maintenance of the wetted mechanical components. In comparison, column flotation provides superior metallurgical performance while offering a lower maintenance demand. Both metallurgical and mechanical characteristics of column flotation are discussed to demonstrate the benefits of this technology for the recovery of bitumen from oil sands.

Jan 1, 2012

By Jeffrey D. Thatcher, Debra W. Struhsacker

With the burgeoning development of precious metals heap leach mining projects throughout the country regulatory agencies are beginning to take a closer look at the short-and long-term environmental consequences of heap leach mining. This increase in regulatory review is occurring on federal, state and local levels, and is affecting both large- and small-scale mining developments. Small-scale mining developments are receiving especially critical regulatory scrutiny because in the eyes of some regulatory agencies, small developers lack the credibility automatically accorded to major mining companies. This is due in part to a bad image of small miners based upon past environmental problems and permit violations caused by a few, small operators. The proponent of a small mining development thus faces special problems during the project permitting process, and must convince the regulatory authorities of his company&apos;s ability and commitment to plan, develop, and decommission a mining operation in compliance with environmental regulations. Not only must the small developer have a thorough understanding of the regulatory requirements affecting his project, he must also devote considerable effort to careful internal planning in order to produce a well organized approach to project permitting. The importance of proper planning cannot be overstated. Project planning is key to convincing the regulatory agencies that the small miner is capable of developing a viable project. More- over, the economics of a small mining project demand permit acquisition at modest cost and in a timely fashion. A well planned permitting effort will thus ensure that permits are received within budget and on schedule. This paper will review the federal, state, and local permitting requirements for heap leach projects, and the variability of these requirements from state to state. The environmental assessment process for projects developed on public lands, and the acquisition of zero- discharge water quality permits, air quality permits, and local special use permits as they apply to small mining developments will be discussed. The paper will conclude with a review of project decommissioning and cyanide neutralization requirements and their implications for small-scale heap leach projects.

Jan 1, 1987

By S. Klein, D. Crouthamel, D. W. Farmer, S. H. Phillips

Groundwater inflows during construction pose one of the greatest risks to the successful completion of tunnel projects. Inflows can result in safety concerns, difficulty in mining and ground support, impact sensitive environmental habitats, create surface settlement and increase costs. Adequately planned pre-excavation grouting programs benefit both the Owner and Contractor in reducing risks and controlling project costs and potential schedule delays. This paper outlines strategic guidelines for assessment of site conditions for pre-excavation grouting hard rock tunnels. It also describes the design of pre-excavation grouting programs with respect to project requirements.

Jan 1, 2005

By R. J. Kline

Most accidents are the result of risk taking. They can happen anywhere. Our coal industry categorizes accidents by type, occupation, commodity, age, every way you can imagine. We now know, how many were injured and when, for all the different types of accidents. We have ask ourselves many times, why are we having accidents, how can we stop the accidents and fatals in our industry? Present numbers and projections do not show that this will happen. Serious accidents can result in fatalities. Fatal accident can be prevented, and the coal industry can achieve zero fatalities. How soon this happens, depends on a great number of factors. I will discuss accidents and reasons for us having accidents in an attempt to get to the root causes. The historical perspective will be touched on, and the risk and analysis of accidents will be probed.

Jan 1, 2000

By John E. Tilton

During the past several years — much to the delight of producing firms and countries — copper prices have surged from under $1 to more than $3/lb. Anyone familiar with the industry also knows that since the early 1970s the long-run trend in real copper prices has been significantly downward. This sharp contrast between short-run and long-run trends raises the issue of the forces behind these developments. What has been driving short-run prices up and long-run prices down? Simple economics suggests that it is all a matter of supply and demand. When demand is rising faster than supply, prices will rise and vice versa.

Jan 1, 2006

By Yngve Jordal, Sverker Hartwig

The IVAR Project is Norway&apos;s largest sewer project presently under construction. One part of it is an 8.1 km (26 575 ft) long, 3.5 m (11 ft 6 in.) diam tunnel, bored in one year. The tunneling project has been running smoothly; however, not everything has been easy. A few of its features are highlighted in this paper: The use of 9 0 (12 cu yd) muck cars on a double track back-up in such a comparatively narrow tunnel. Employing only four men in the tunnel, including the loco driver. A quartzite dyke - 96% quartz with 350 MPa (50 000 psi) and more compressive strength - turned out to be 640 m (2 100 ft) thick instead of the predicted 90 m (300 ft). Passing under a gaseous swamp with only same 5 m (16 ft 5 in.) of rock cover on top.

Jan 1, 1991

By Claudio Flores Martinez

The prospect of accomplishing economically and scientifically profitable deep-sea mineral mining within this decade or the next one is of particular interest to the emerging discipline of astrobiology which is concerned with the origin, distribution and future of life in the Universe. Several planetary bodies within our own Solar System such as Jupiter’s moon Europa and Saturn’s Enceladus now appear to be potentially habitable, or life-friendly, in terms of the three prerequisites for life as we know it: a sustained body of liquid water, biogenic elements (C, H, N, O, P, S) and energy sources to fuel metabolic reactions. Europa, for instance, possesses a global subsurface ocean, believed to be up to 100 km in depth, hidden beneath a kilometer-wide ice-sheet. A silicate mantle is directly interacting with a cold, aphotic ocean in which tidal forces might drive geological seafloor activity that results in the creation of hydrothermal systems. These locales are commonly hypothesized to be the cradles for an alternate origin of life on Europa. Especially alkaline hydrothermal springs, as found at Lost City, have been at the center of modeling the prebiological evolutionary dynamics preceding cellular life. Serpentinization-like reactions are also possibly fueling metabolic networks in putative microbial communities found in the oceans of the icy moos. Major space agencies around the globe are planning future space missions aimed at exploring and eventually characterizing potential life forms in these habitats. The technology needed for this exploration effort resembles the requirements for a successful deep-sea mineral mining industry: highly efficient AUVs (also equipped with biologically-oriented instrumentation), swarm robotics, landers, seafloor rovers and general high-pressure, cold temperature extreme environment engineering. Interestingly, science questions of deep-sea mineral mining and astrobiology converge too: the hypothesis of life originating at hydrothermal systems, the biogeographical distribution of species among these environments, adaptations of extremophilic organisms across the three domains of life and adequate autonomous robotic systems to assess the complexity of deep-sea biological communities. This presentation attempts to present a two-fold view of advanced planetary exploration that relates to a sustainable vision of deep-sea mineral mining: charting our oceans and developing technologies least harmful to endemic biology can propel the design and prototyping of future robotic planetary probes bound for aquatic missions on alien moons. Space industry, government and public interest towards a broadened planetary perspective on deep-sea mineral mining is promoted by addressing an astrobiological rationale of this endeavor.

Sep 1, 2014

In longwall mining, premining prediction of methane emission rate depends on a number of geological factors, geographical factors, and operational factors. These same factors also can impact the selection of a specific degasification system. This study proposes a principle component analysis (PCA) and artificial neural network (ANN) approach to predict the ventilation methane emission rates of U.S. longwall mines and the optimum combination of degasification boreholes based on the given characteristics of the mine. Artificial neural networks, more than conventional computer models, are adaptable systems that can solve problems such as non-polynomial or very complex relationships that are difficult to describe mathematically. Data on ventilation emissions and degasification system design were obtained from 63 longwall mines in 10 states and were combined with corresponding geological, geographical, and operational parameters for the period 1985-2005. PCA was used to determine the variables that most influence ventilation emissions and degasification system design. Different combinations of variables in the data set and network structures were used for network training, cross-validation, and testing. The resultant ANN models predicted ventilation methane emissions with a 90-95% accuracy and were superior to multi-linear and second order non-linear models. The ANN-based expert classification system was able to classify the design of the degasification system (no degasification, gob vent borehole, horizontal and gob vent borehole, and horizontal, vertical and gob vent borehole) with more than 80% accuracy. The models can be used as prediction and decision tools for the ventilation emissions and degasification system selection for specific site and mine-design conditions.

Jan 1, 2009

GE Industrial Systems has received a multimillion dollar contract from Bucyrus International to supply complete electrical systems for three new draglines. These machines will be installed at Coal India’s Northern Coalfields’ Dudhichua and Nigahi open cast mines. The Dudhichua and Nigahi mines are located south of Varanasi. They produce Type C and Type E coal for use in the region’s super-thermal power stations. The GE systems will power and control the drag, hoist and swing motions of one Bucyrus W2000 walking dragline at Dudhichua and two a Nigahi.

Jan 1, 2000

By Michael Amick, G. Swan, R. Hill, C. Pritchard

Falconbridge, a major base metal producer in the Sudbury Basin of Ontario, identified a need to find a safe and cost effective replacement for welded-wire mesh used to support loose ground during underground nickel mining. Falconbridge took a methodical approach to the concept of a spray-on liner as a screen replacement proving the strength characteristics of the liner as a safe, cost effective, and suitable method of supporting ground. Compact, hydraulic mixing and spraying equipment have been developed and are in use at the Fraser mine. The Tekflex material has been approved as a wire-mesh replacement and has been in use since November1998.

Jan 1, 2000

Every two years, industry leaders and practitioners of tunneling and underground construction gather at the Rapid Excavation and Tunneling Conference (RETC) to learn from their peers about the most recent advances and breakthroughs in this unique fleld. Industry experts from around the world highlight their most recent projects and share real-world experiences. They also share with their colleagues new technologies and methodologies that attendees can take home to their respective projects. The 2013 RETC was held June 23-26 in Washing-ton, D.C., itself home to several major tunneling and underground construction projects. The conference is sponsored by SME. Attendance was 1,384 professionals. The accompanying exhibit hosted 159 companies in 188 booths. A few of the topics covered in the technical sessions dealt with caverns and large spans, contracting practices, tunnel linings, design and planning, geotechnical considerations and instrumentation. The conference was preceded by four short courses, all well attended. They were ?Grouting in Underground Construction,? ?Tunnel Lining Design,? ?Microtunneling Application? and ?Risk, Uncertainty and Hard Decisions.? In addition, a sold-out field trip to D.C. Water?s Blue Plains Tunnel took place following the conference. The Blue Plains Tunnel is part of the agency?s Clean Rivers Project. Also during the meeting, three students each received $5,000 scholarships from the UCA of SME, while another three students each received $2,500 scholarships from RETC (See page 53).

Sep 1, 2013

By J. Sandford, S. Hennings

EXECUTIVE SUMMARY An approach borrowed from the petroleum industry was applied to the gas development evaluation for the Bulga underground coal mine in New South Wales, Australia. The results enabled the coal mine operator, Xstrata Coal, to systematically plan the extraction of gas in harmony with mine production planning of multiple coal seams. This has allowed for a more proactive approach in preparing the resources and infrastructure needed to capture the gas and accelerate coal mining while maintaining their high level of commitment to safety. Norwest has for decades used gas recovery simulation models to assist the petroleum industry and the coal bed methane (CBM) industry in understanding and forecasting fluid saturations and flow behavior. Norwest developed a similar process with Xstrata to migrate existing mine data at Bulga into reservoir simulation models to study various drainage alternatives. An interesting feature to the evaluation was also developing an understanding of test procedures and nomenclature from the mining industry to properly translate the data for input in simulators developed for the petroleum and CBM industries. The model was then calibrated to actual field data collected from drainage pilot tests that Norwest helped design and monitor at Bulga. The resulting calibrated predictions were then used to develop budgets, schedules, resource requirements, and alternatives for capturing the gas and delivering it to market ahead of mining. Increasing revenue, reducing emissions, improving schedules and cutting costs for the mining operations have all contributed to justifying this advanced approach at Bulga. It has also allowed Xstrata to expand their focus to the sizable gas reserves in seams not currently planned for mining. Several of these seams would be economic gas development targets once the gas recovery infrastructure is installed for the mine. The evaluation process was refined throughout this project and the resulting approach will benefit Xstrata with their broader strategic development of resources in the Hunter Valley and beyond to their worldwide operations.

Jan 1, 2007