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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.

By Tom Martin

Mega projects present unique challenges with regard to estimating costs. With such projects, which may span decades, these challenges often begin as soon as a project is conceived. The importance of having a sound, resource based estimate avail-able early in the process cannot be overstated because it provides the basis for ongoing project decisions. For the final phase of providing an updated cost estimate, often while bidding by contractors is underway, the Engineer?s Estimate (EE) must incorporate present market conditions; account for possible volatile material price swings; be based on actual labor and fringe costs; rely on meaningful productivity rates; and accommodate any recent technology advances while identifying and allowing for risk factors. This paper explains the benefits associated with consultants adopting a contractor?s estimating approach when preparing the Engineer?s Estimate on mega projects like the various tunneling projects in New York City.

By G. Karahalios

Industrial minerals have always enjoyed an important share in the technological growth of any country in the world. Today, extraction and trading of industrial minerals has expanded, but is also subject to stricter environmental guidelines. This paper presents the current status as well as the growth potential in the exploitation of industrial minerals in the countries of the south eastern European region, i.e. Albania, Bosnia-Herzegovina, Bulgaria, Croatia, F.Y.R.O.M., Greece, Italy, Serbia and Montenegro, Slovenia and Turkey. More specifically, annual production figures per country are presented for1992-1998. These figures are compared to each other and, where applicable, to world production figures. Trading of industrial minerals from these countries to Europe and the world and its effect to the local economies is also evaluated were such data is available.

Jan 1, 2000

By A. Steinmüller

Introduction In the design and operation of gravity concentration circuits, the application of process models for spiral concentrators offers significant benefits. A substantial amount of work has been produced over the last 30 years in the field of modeling the metallurgical performance of spiral concentrators. It is not the aim of this contribution to add to the refinement of modeling technique but to share some of the experiences and potential improvements which can be achieved in a relatively simple way. The design of spiral circuits usually requires extensive testing. This is often conducted in batch operation only, either due to lack of suitable continuous testing facilities, the unavailability of sufficient quantities of sample, or other constraints. Typical problems arising during circuit development from batch testwork are the extrapolation of results to different feed conditions, and resolving of internal recycles. Model selection and development The classic approaches in spiral modeling technique range from fundamental fluid dynamics, based on the Navier-Stokes equations in combination with expressions for local slurry properties, to fully empirical and statistical models. With the initial objective of developing an in-house tool for gravity circuit optimization and development, mathematical model types from each category, available either commercially or in the published literature, were evaluated. Model selection For the desired purpose, an approach proposed by Holland-Batt (1990) was found suitable, which was adopted and modified. Holland-Batt reported that the shape of release curves in spiral applications could be described by a combination of a linear function in the initial recovery zone, and a power law function outside this zone. The proposed recovery function was formulated as

Jan 1, 2005

By John E. Newby

The Brightwater Conveyance System consists of four tunnel segments in three tunnel con-tracts, comprising over 21,760 m (71,400 ft) of pressurized face tunneling in complex glacial and non-glacial soft ground conditions with a large proportion 60 m (197 ft) or more below the ground surface with up to 7 bars groundwater head. This resulted in unique technical challenges for establishing geotechnical baseline values. The process used to develop these baseline values and specifications with regard to the level of risk that the owner, King County, was willing to accept is described in this paper.

Jan 1, 2008

By M. Mikhaylenko

The most common methods of processing of uranium ores is sulfuric or carbonate leaching with conversion of hexavalent uranium to uranyl carbonate or sulfate anionic complexes followed by sorption of the later by strong base anion (SBA) exchange resins. It is known that chloride anion has high affinity for SBA resins so that it depresses sorption of anionic complexes of uranyl. Application of the SBA resins becomes impractical for recovery of uranium when chloride concentration in pregnant leach solution exceeds 3-5 g/l [1-3].

Jan 1, 2012

By Don F. Macfarlane

This paper describes the field application of the NTH fracture classification to rock encountered in the construction of the 9.6 km long, 10m diameter, Second Manapouri Tailrace Tunnel. Excavation of the tunnel was undertaken by TBM between 1997 and 2002, in gneisses, granitic and diorite rocks. The paper outlines an adaptation of the NTH fracture classification used during the geological logging of this tunnel. The NTH fracture classification was primarily applied to assess discontinuity spacing for tunnel support requirement decision-making. The paper includes some general comparison of NTH classes with overall penetration rate.

Jan 1, 2008

By O?Connor. D. F.

The ever increasing energy costs associated with mining at depth has become an important issue that needs to be addressed for future sustainable production. Vale Inco Limited?s Creighton Mine being the deepest has the highest energy cost per ton due to the ventilation system requirements. A review of the ventilation systems was undertaken with respect to current practices and identification of opportunities to the practical application of technology that would facilitate energy savings. Energy conservation initiatives such as time of day controls have been implemented; however there still remained some opportunity for further reduction. Based on previous studies that identified opportunities due to actual time spent in the workplace, our mining method and ventilation design, it was determined that Ventilation on Demand (VOD) could provide further additional energy reductions with respect to our auxiliary fans. A pilot project has recently been initiated to apply a Ventilation on Demand concept to two 112 kW auxiliary fans and their related workings located on the 2340m level of Creighton Mine. The project objective is to determine the practical methodology and application of this technology in the field. This project involves the installation of variable frequency drive (VFD) starters on the auxiliary fans to allow variable volume (through speed control) based on demand. The required flow is determined based on equipment and/or personnel via identification tags. The Fans adjust to the flow requirements as measured by flow sensors. Since the fans are sized for the final requirements the required flows can be achieved regardless of system length. Energy savings are realized by supplying only the volumes (power) as required and only when required. This paper discusses the rational and program being tested at the VALE Inco Limited, Creighton Mine.

Jan 1, 2009

By R. K. Sinha, B. S. Choudhary, Desh Deepak, A. K. Mishra, Hemant Agrawal, Shankar Kumar

There are several methods (empirical, statistical, and machine learning tools) to calculate blast-induced ground vibration. Still, due to complications in the blasting procedure, under varying blasting loads and strata conditions, it is not easy to predict and simulate blast vibration precisely. Therefore, a study was conducted to simulate the field blast data in Ansys software using explicit dynamics. For this study, monitoring of ground vibration for 20 single hole blasts was carried out. The density of emulsion explosives was in the range of 0.9 to 1.15 g/cc. In the laboratory, rock properties were determined from the rock sample collected from the mine site before blasting. The in-hole velocity of detonation (VoD) and the density of the emulsion explosive were also determined. These parameters were used for numerical analysis to know the ground vibrations at specified points. The results of ground vibration predicted by the model are validated using field data.

By J. M. Hollow, D. E. Walsh, H. K. Lin, J. L. Oleson

At the Fort Knox Mine, Fairbanks, Alaska, carbon fines are generated during stripping, acid washing and kiln regeneration operations. Carbon fines are collected by a filter press because of their gold value. Samples of the carbon fines show that they consist of 20-30% carbon, 70-80% grit and 0.17-0.68 kg/t (5.0-19.9 oz/st) gold. About 80% of the gold values in the carbon fines used in this study are in a form of recrystallized free gold grains, with the balance being adsorbed gold on the carbon. High recoveries of gold and carbon were obtained in laboratory tests using froth flotation, with a high rejection of the grit.

Jan 1, 2001

By Charles C. Dahl, Gordon C. Presley, Andrew E. Nevin, Bruce A. Kennedy

How does SME-AIME cope with profound changes in technology, markets - and most importantly - in employment patterns facing its membership today? This is the question that prompted the Society's Board of Directors to appoint a Long-Range Planning Commission (LRPC) (see ME, Feb. 1984, pp. 118 and 128). This is also the question addressed most particularly by the LRPC's Scope Committee. The Committee started its deliberations by asking such basic questions as "Who are we?" and "What is our business?" The Scope Committee then reviewed the findings and recommendations of other more specialized committees to develop and integrate their concepts of the Society's business for the next 10 years. The policy-making suggestions of the LRPC were reviewed and acted upon by the Board of Directors at its open meeting in Los Angeles on Feb. 26, 1984. At the Oct. 23-26, 1984 SME Fall Meeting in Denver, the Board will again review LRPC recommendations. In answer to the question "Who are we?" the Scope Committee proposed description, which was accepted by vote of the board of directors: . . A technical and professional organization that consists of individual members, namely those mining engineers, metallurgists, geologists, earth scientists, economists, managers, educators, and other professionals concerned with all facets of exploration, production, distribution, and using of mineral commodities. "These mineral commodities include all metals; industrial minerals, including construction materials and fertilizers; coal, oil shales, tar sands, and other mined fuels. Among the earth's mineral resources, only wellpumped oil and gas lie outside the Society's specific purview. "Traditionally, SME members work in the fields of engineering, technology, exploration and discovery, development, construction, mining, quarrying, beneficiation and processing, handling and transport, equipment manufacturing, sales and marketing, data processing, safety, land reclamation, environmental protection, taxation, administration, and management of these elements. "Members practice their professions in industry, in universities and research institutions, and in government. They may be operators, manufacturers, sales persons, contractors, consultants, analysts, researchers, educators, advisors, regulators, or members of supporting staffs. "The members of the Society are leaders in dedication to their crafts, in innovation, and in the pursuit of excellence. Among their numbers they count the most distinguished of engineers, applied scientists, and managers. "The Society is based in the United States, is active on a worldwide basis, and is open to nationals of any country. Certain qualifications must be met for attaining and maintaining membership." Purpose of the Society As to the question "What is our business?" the Scope Committee restated our purpose in light of current practice and the constitution of AIME and the bylaws of AIME and SME. The Board of Directors accepted the following proposed purpose of SME: "To further the professional development and well-being of its members by publishing and distributing technical writings, news, and information; by sponsoring meetings of members; by providing forums for discussions and for continuing education; and by fostering communication on the subjects within its purview. "The Society assists educa-

Jan 4, 1984

By Atmesh K. Sinha

Death and injury rates in mining have been the highest of any industry; the injury severity rates in mines have also been the highest. Tentative figures reveal that 1971 was the best year yet for the bituminous coal indus¬try with the lowest number of fatal accidents. Nevertheless, 177 men were killed at a frequency rate of 0.76 per million man hours. Coal mine accident statistics have been described at various times as unacceptable and intolerable and recently resulted in the enactment of massive legislation. The 1969 Coal Mine Health and Safety Act was passed by Congress "to improve the working conditions and practices in coal mines and to prevent accidents and occupational diseases originating in the coal mining industry." The prevention of accidents in coal mines is the statutory responsibility of mining engineers and the moral responsibility of all who have any part to play in mining coal. The questions to be answered by these men may well be - What are the reasons for the high accident rate? Are the mines as safe as they can be? Are our mines sufficiently manned to insure proper supervision of production cycles and safety requirements? Are our plans for safety committees, safety campaigns, and safety inspections sufficient? Are they producing the results intended? If not, how can these be reorganized to have a greater impact? What is the real cost of an accident? What are the immediate and long-term plans for further improvements? These questions are in no way exhaustive, and the answers are not easy. There are many aspects of mine safety, and any one of them can be the subject of a lengthy discussion. The aim of this paper, therefore, is to limit the analysis to documented fatal electrical accidents in mines so that meaningful conclusions for improvement in electrical accident-experience statistics can be made. In doing this, it is also the intention to emphasize areas of missing information and propose a few suggestions for better hazard analysis.

Jan 1, 1972

The ability to optimise a concentrator from mill feed to final products requires a simulator which integrates comminution, classification and separation modelling. In order to model this range of processes, such a simulator must handle a variety of information about the ore. The AMIRA P9 project has developed a whole-of-concentrator simulation capability which brings together a texture-based model of mineral liberation, quantitative X-ray micro-tomography analysis to measure the inputs required by this model, and a multi-component simulator software framework. In the context of this approach, the term ?multi-component? implies the ability of the simulation to handle many particle properties simultaneously; for example size, composition, density, floatability etc. The simulation software framework provides the means to manage the flow of data around a circuit flowsheet, allowing each process model to access the information relevant to that particular model. A case study based on plant data from a gold-bearing pyrite concentrator is used to demonstrate the capabilities of the multi-component approach in simulating circuits which contain comminution and separation processes.

Feb 27, 2013

By B. K. Belle

The use of diesel engine locomotives in South African mines can be traced to Van Dyk Consolidated Mines Ltd on the Witwatersrand gold mines in 1928 as a replacement for battery locomotives. The advantages and disadvantages were recognized in those days, and surprisingly, there are no significant additions to this list, but only refinements. In the absence of any Occupational Exposure Limit (OEL) for Diesel Particulate Matter (DPM) in SA, the Mine Safety and Health Administration (USA) rule is currently being used as a benchmark for the ventilation engineering designs. This paper discusses the ongoing SA journey of measurement and limitations of exposure data for ventilation planning and regulatory purposes. The currently accepted DPM limits are based upon the belief that they are economically and technically feasible for the mines to reach and are not necessarily health based. For SA underground platinum mines, a median TC/EC ratio of 1.8 with a range of 1.2 to 5.8 was observed. For SA coal mines, a median TC/EC ratio of 1.44 with a range of 1.25 to 2.13 was observed. While it is common practice in the USA to use the ratio of TC/EC for metal mines to be 1.3, the ratio found in local platinum mines is 2.2 and for coal mines, the ratio was 1.53 which is lower than Australian studies, i.e., 1.96. It has been shown that a need for critical analysis of TC/EC ratios exists, and possible reasons for variance must be understood before stringent adoption of overseas recommended limits for DPM. It is hoped that the findings from this paper would provide input to scientific approaches in developing appropriate conversion factors, limits for DPM and also in ensuring appropriate error factors (currently 1.14 for TC and 1.2 for EC) for compliance determination.

Jan 1, 2009

The ability to track miners and communicate with them while they work in underground coal mines is important during normal daily operation, and critical in emergency conditions. This was evident during recent incidents at underground coal mines worldwide. Communication with miners and the knowledge of their location is of great importance for rescue efforts and the preservation of life. Numerous technologies have been developed, adapted and deployed to meet tracking requirements of the Mine Improvement and New Emergency Response (MINER) Act of 2006. Evaluating the performance of these systems has proven to be dif?cult for mine operators, system manufacturers and regulatory agencies. The MINER Act requires operators to improve accident preparedness by developing an emergency response plan speci?c to each mine. With the recent implementation of the provisions of the MINER Act of 2006, all underground coal mines in the United States are subject to the mandates of legislation concerning communication and tracking system installation. As of June 2011, 203 new or revised tracking and/or communication systems had been approved by the U.S. Mine Safety and Health Administration (MSHA), with nearly 50 other systems or revisions in the approval process (MSHA, 2011). At that time, the available approved systems for underground coal mine use included these types: ? Leaky feeder communication systems. ? Fixed node-based communications and/or tracking systems. ? Wireless node-based communications and/or tracking systems. ? Medium frequency (MF) communication systems. ? Communication system peripherals. Other types of tracking systems have since been developed and some manufacturers are seeking approval for use in this application. Some of the new products include through-the-earth (TTE) systems and various radio frequency (RF) adaptations. New technologies that are currently being developed and deployed in other industrial applications should also be considered, including acoustical, optical, inertial and hybrid technologies. To date, no uniform method has been employed in the industry to effectively compare and evaluate the performance of installed systems. Neither industry operators nor regulatory agencies can accurately assess the capabilities of installed systems in the continuously changing mine environment. There is a need for a uniform evaluation method that provides the ability to assess how different systems and technologies perform in various mining applications, and whether they can satisfy the regulatory requirements.

By Samuel J. Gambino

Preliminary recommendations for the Upper Northwest Interceptor 1&2 specified installation of reinforced concrete pipe using pipe-jacking methods. However, a larger one-pass tunnel constructed using precast segmental lining would provide additional storage volume. The risk of encountering unexpected conditions or events and the resulting cost impacts could differ significantly for these two options. A probabilistic life-cycle cost analysis of these alternatives was performed. This paper discusses the construction alternatives considered, the risk assessment methodology used to evaluate these alternatives, the input parameters and risk factors used in this analysis, and the recommended project which is currently being constructed.

Jan 1, 2008

By Warren G. Burres

or more than 50 years the Portland Cement Association has represented the United States cement industry in matters relating to the technology and use of cement and concrete. Interestingly enough, PCA?s emphasis has been on concrete and its uses rather than on Portland cement. The cement industry realized long ago that cement is basic and serves its fundamental purpose as an ingredient in concrete. Cement could never be successful if concrete were not. Work with the users and specifiers of concrete had to be done at its end point of application--in a building, bridge, dam, highway or home. PCA, over its half century of existence, has been dedicated to this job. I should like to talk to you today on the less technical side of concrete--what it has been--what it is today--and what it can offer in future construction. Concrete, in many forms, has a long background extending from such notable historic times as the Roman Empire. Here, concrete made from pozzolanic cement from the slopes of Mt. Vesuvius was used to construct the Coliseum, home of the Roman circus; for the Appian Way, the ancient forerunner of the Interstate system; and the miles of aqueducts throughout Europe, many of which still carry water. In 1811 Joseph Asppin, an English bricklayer, made the first modern cement by the artificial mixing of pulverized limestone and clay materials. Ht,

Jan 1, 1971

By H. Maleki, G. Tetreault

This study was initiated by the Bureau of Land Management (BLM) to develop guidelines for determining the maximum economic recovery of resources in coal mines. The work was in response to a requirement in the Mineral Leasing Act of 1920 and Federal regulations. The intent was to address the economic rainability of small, irregular reserves in existing longwall mines. In particular, there was a need to determine if room-and-pillar mining using a continuous miner (CM method) was economically sound, or whether unconventional (short or odd-shaped) longwalls could be used to recover small coal reserves economically. Small reserves, called "widgets" are left in longwall mines on one side of the mains, near outcrops and adverse geological conditions, or near any other location where reserve geometry does not lend itself to mining with a rectangular longwall panel. The work included (1) analysis of the geologic, geo-technical, and economic factors that influence the recovery of small coal reserves, (2) analysis of historic changes in supply, demand, and coal prices, (3) development of typical cost models for room-and-pillar and longwall mines, and (4) development of a practical methodology for determining maximum economic recovery. The methodology included an evaluation of the ratio of coal mined during longwall mining to that mined for development (LDR) as well as costs of maintaining coal quality depending on market conditions. The LDR is a good indicator of mine efficiency and overall coal recovery in modem longwall mines and thus is used to evaluate the

Jan 1, 2001

By R. J. F. Goodfellow

Many underground projects now include preparation of a Risk Register through planning and design as a tool for project and risk management. There is still significant discussion within the industry as to whether and how to best present the Risk Register through the bidding process and the construction phase of a project. While the ITIG Code of Practice for Risk Management of Tunnel Works recommends this approach of continuity in risk management procedures, it is silent on the specifics of how this should be achieved. This paper will explore the perceived benefits and disbenefit of including the project Risk Register with bid documents; format and content that should be transferred and lessons learned using the case history of bidding and early construction phase of the Bi-County Water Tunnel in Montgomery County, MD

Geopolymerization is a process by which Al-Si minerals undergo dissolution and polymerization in an alkaline solution to form a monolithic material with a high mechanical strength (Davidovits, 1991; 1994). In this study, Na-feldspar (albite) and K-feldspar (microcline) have been selected to investigate their abilities to undergo geopolymerization. The interaction between alkali metals present in the alkali-feldspars and alkali metal cations contained in alkaline solution during geopolymerization has also been studied. It has been found that both albite and microcline can be applied in geopolymerization to produce geopolymers with a high compressive strength. Although the dissolution of M-feldspar (where M = Na and/or K) in concentrated MOH solution is inhibited when the alkali metal cations of the alkaline solution differ from the alkali metals structured in M-feldspar, the resulting geopolymers are found to demonstrate a higher compressive strength. Moreover, a proper molar ratio of Si/Al in the geopolymeric gel phase and a higher average hardness of the undissolved particles remaining in the geopolymers are found to greatly increase the ultimate compressive strength of the geopolymers.

Jan 1, 2002