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By T. Doshi, S. Ennis

The interactions of mineralogy, chemistry and mechanics in an ore concentrator are highly complex, so it can be particularly hard to measure the impact of a specific plant change. This paper describes a method for modeling a baseline metal recovery so that the value of a major process improvement can be measured. This method only considers variables that cannot be optimized, such as mineralogy or equipment availability. Linear regression, random forests, extreme gradient boosting (XGB), and simple two-layer neural network models of process value were tested as candidate baseline model types to assess the impact on throughput and recovery in a copper concentrator. XGB performed the best in terms of accuracy for both throughput and recovery models. Using an XGB model of nonoptimizable process variables provides an accurate, dynamic baseline that can be compared with continuous production data to determine the value added by major concentrator improvements in real time.

Mar 2, 2022

By John S. Cummings

Although there are many geologic situations which might be discussed at a session such as this, as I considered the problem, it became apparent to me that I should discuss a situation which has been of concern to me, and should be of concern to the geologic community. As a result, the questions which I will pose, and the criticisms, have not been arrived at quickly or easily, but have accumulated through time, to the point where I feel discussion is necessary. Very briefly let me say that my criticism of geologic mapping, of conclusions reached, and objectives or lack of such, results from my association with many areas where such studies have been completed, and resultingly my inability to comprehend the system of evidence or logic which supports extensive age-formational designations. The heart of the problem is that many conclusions resulting in geologic designations are based on weak or non-existent evidence, and such should be catagorized as hypotheses. Although the geologic community as a group does not approve or disapprove of such designations, it is evident that many or most of such designations attain a "status", and arc accepted as more or less valid statements. As will be shown, the amount of specific lithologic data provided in some quadrangle mapping projects is exceedingly slim. However, of concern herein is that the type of information presented at any stage is sufficient to warrant conclusions drawn. To see the magnitude of the problem, it is probably necessary to review some basic fundamentals upon which our geologic systems are established. The United States Geological Survey has defined a "formation" as the broad unit of geologic mapping consisting of a large and persistent stratum of one kind of rock. Obviously such a designation allows that a formation could be considered "time variant" in a horizontal as well as in a vertical context. However, other definitions enable a formation to mean units

Jan 1, 1972

By Reece Kurre, Gabriel Walton

"Roof bolting has long been used in underground mines across the world to provide ground support. Modern roof bolts are cheap and easy to install with the use of specialized machines as a part of the production cycle. Lhoist North America’s Crab Orchard Mine is an underground room and pillar limestone mine that uses mechanically anchored roof bolts for ground support. The mine currently employs two different roof bolting patterns: a standard 5 × 5 foot pattern, and a 2.5 × 2.5 foot pattern for use in areas with particularly hazardous roof conditions. The purpose of this study is to evaluate the relative effectiveness of each bolting pattern.A series of numerical models were created using RocScience’s RS2. The models were based on a symmetrical section of the mine at its deepest point, and were modeled using Generalized Hoek-Brown failure criterion along with a discrete fracture network. A series of sensitivity analyses were performed on the models by varying parameters such as joint friction angle, crack persistence, joint randomization, and tensile strength of the limestone. Based on the results of the original models and sensitivity analyses, it appears that the standard bolting pattern provides sufficient roof support capacity under almost all the expected conditions at the mine, since factors of safety below the design value of 1.5 were only found for individual bolts in a few of the worst test cases considered. These results can help improve the Mine’s productivity and reduce operating costs without compromising safety.INTRODUCTION AND CASE STUDY DESCRIPTIONLhoist North America’s Crab Orchard Mine is an underground limestone mine located in Crab Orchard, Tennessee. The mine is located under an 800-foot-high mountain, and outcrops on three sides. The mine is accessed through three separate portals and has two main levels, along with a partially developed third level. Extraction is accomplished by the room and pillar method using 50 × 50 feet pillars and 50 × 50 feet rooms. The mining height is limited to 50 feet to keep the pillar width to height ratio around 1.0. Each heading is excavated in a two-stage process that consists of a 30-foot-tall top heading and a 20-foot-tall bench. A distance of at least 30 feet is maintained between the two levels at all times (Crab Orchard Mine Technical Staff, 2017)."

Jan 1, 2019

By Andrew B. Cecala, Robert J. Timko, Christopher J. Pritchard

As mine venti1ation systems become more complex, it is increasingly difficult to supply fresh air to the working face. A high percentage of the fresh air entering a mine never reaches the working face because it short circuits through stoppings and doors, exiting the mine without being utilized. When ventilation limits are reached, the only option presently available to most U.S. mines is to sink a new shaft - an extremely expensive undertaking that many companies cannot afford. Reusing or recirculating a percentage of ventilating airflow may make it possible for some mines to remain operational while maintaining a safe environment for workers. Such a study was performed at a trona mine in Granger. Wyoming. A vane axial fan was used to recirculate approximately 9.4 m /s (20,000 cfm), 25% of the total ventilating airflow, back to the working face area of a three-entry continuous miner section. This study involved two evaluations: the first when the face was 305m (1,000 ft) from the recirculation fan, the second when the face was 610m (2,000 ft) from the fan. The evaluation consisted of monitoring the mine atmosphere for respirable dust, methane (CH4). carbon monoxide (CO), and nitric oxide (NO), at various locations in the intake and return entries. Several shifts were monitored, with and without the recirculation system in operation. With the recirculation system in operation. there was an increase in measured respirable dust concentrations in the intake along with a slight increase in the mine temperature (1.67°C). There were also some minor changes in CO and NO levels in the intake entry, but this seemed to depend on the proximity of the instruments to the turn-around point for the diesel haulage vehicles, than to whether the recirculation system was or was not in use.

Jan 1, 1989

By Y. C. Kim

This paper describes the implementation aspect of a blast hole kriging system which has been developed for the purpose of daily ore-waste control in an open pit mine. The primary goal of blast hole kriging is to improve the ore-waste delineation procedure. A complete computer program package called Blast Hole Kriging (BHK) System was developed for IBM/PC AT or XT computer, using Fortran language and supplemented by a few Assembly language routines for bit-map manipulation. The emphasis of this paper is on the implementation aspect of the developed system. For this reason, the requirements for practical implementation and the system design considerations are discussed in the paper, as well as the main features of the University of Arizona's BHK System.

Jan 1, 1990

By Xuehui Zhang, Yun Bai, Qiaosong Li, Huiming Wu

"Construction activities account for a large share of the global Greenhouse Gas emission. In the past 10 years, project decision-makers and researchers have been paying more attention to the carbon emission of tunnel projects. In this paper we study the carbon emission calculation in shield tunneling. The objective of this paper is to: (1) analyze the complex variables which affect the total emission of shield tunneling; (2) develop and illustrate a new data-mining-based method to estimate the carbon emission in the construction phase; (3) assess the emission prediction reliability of a data-mining-based method—the Randomforst model, with R programming language. This study is based on a large-diameter shield tunnel built in Shanghai, China, and shows that a reliable predictive performance can be achieved with this new data-mining-based method. INTRODUCTION Climate change caused by the Greenhouse Gas (GHG) emission has been a hot topic in recent 20 years. Both governments and non-government-organizations are trying its best to control the climate change. Since the 1990s, the general consensus is that carbon emission reduction and carbon sinking (the work of capturing the emitted carbon) are two ways of mitigating the global warming effect, with the former being more exercisable. The challenge posed by global warming also motivates the project decision-makers to take measures to reduce the GHG emission. The 5th Assessment & Report on Climate Change (published by IPCC, the Intergovernmental Panel on Climate Change) suggests that building industry contributes to 5% of the total direct emission. The building industry has shown more awareness of the impact of GHG emissions with construction activities. Shield tunnels act as an important component of the infrastructure system, and have been the dominant way of utilizing the underground space, as well as a competitive alternative to passageway underneath rivers. To study the environmental effects of shield tunneling, there is a need to quantify the carbon emission of shield tunnel construction."

Jan 1, 2016

By G. W. McCaa

Plans for a large industrial development in the Upper Ohio Valley between Moundsville and New Martinsville, West Virginia, were announced in the Fall of 1955. This development consisted of a large aluminum plant to be .built by Olin-Mathieson; a 675,000 KW power plant to be constructed by the American Electric Power Service; and a large coal mine adjacent to the power plant to be developed by the Hanna Coal Company Division of Consolidation Coal Company. The Ireland Mine was designed to efficiently supply fuel for the power plant, and this was the first consideration in the location of facilities, design, and development of plant and the selection of the equipment. The first problem was to find a suitable area for the surface facilities. A level bottom area south of the power plant was reserved for future industrial plants and this area was also blocked off from the coal reserves by an old abandoned and flooded mine. The coal storage facilities of the power plant were on the north side of the plant and it was decided to locate the coal mine preparation plant on-the shoulder of a hill above the power plant. This location required the excavation of 70,000 yards of rock but permitted the driving of a belt slope from the plant at an angle so that the haulage roads underground would miss the abandoned Cresap Mine. This location also permitted the plant to be located at an elevation so that the conveyors leaving the plant were horizontal and had sufficient clearance above the highway and railroad tracks. The other surface facilities consisting of air shafts, supply slope, supply yard, office, bathhouse, shop and warehouse were located in the valley some distance north of the preparation plant. This location placed these facilities one mile nearer to the working area. Plans for design and development of the mine were started in November 1955; grading and clearing of surface area was started in January 1956; the air shafts and slopes were started in the Spring and Summer of 1956; and the first coal was produced from the supply slope in October 1956. The preparation plant was put in operation in March 1958, and by July 1959 was producing 8,000 tons per day.

Jan 1, 1959

By R. A. Franks

An evaluation of a nuisance-emissions-discriminating smart mine fire sensor system was made in an operating coal mine. These field evaluations were conducted to determine the sensor system?s ability to discern nuisance emissions, such as diesel exhaust, emissions from flame cutting and welding operations or hydrogen gas from a charging station, from real fires and to compare the number of falsely reported fire alarms generated between the sensor system and a standard carbon monoxide (CO) monitor. The sensor system?s ability to operate successfully in the working environment of an operating coal mine was also evaluated. The smart mine fire sensor system consisted of four sensors whose data outputs were fused with the use of a neural-network-type computer program. Long-term trials were conducted in a haulage way, a belt entry, and a track entry. The system functioned successfully in the belt entry, in accordance with its developmental goals, where the sensor system even discriminated events not anticipated during development. It was not totally effective in the haulage way and track entry, though, due to a combination of significant diurnal air temperature variations, dust, and mechanically induced vibrations. Also, deteriorating rib conditions contributed to operational problems in the haulage way evaluation. In general, the smart mine fire sensor provided nuisance emissions discrimination and was shown to be a viable new approach for mine atmospheric monitoring, enhancing miner safety. This paper describes the in-mine evaluation of the smart mine fire sensor system and discusses recommendations for improving the system. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2008

By J. M. Rotter, R. A. Lohnes, J. Y. Ooi

Reliable prediction of wall pressures in a coal silo demands careful characterization of the stress-strain properties of the coal. This paper describes the results of triaxial compression tests on a typical fine-ground coal used in power generation and describes the fitting of several different constitutive models to the data. The fitted parameters for the constitutive models are well suited to application infinite element analyses. The different models are used to give the reader flexibility in choosing a model and to show the shortcomings of some models. To explore the quality of the fitting process, the fitted results are compared with finite element predictions of the triaxial test itself.

Jan 1, 1998

By Jay Hilary Kelley

A ventilation system is described using dual aircourses: one zone occupied by working personnel, the other at the active working face. The two zones are separated by a partition or Shroud. The occupied zone to the rear of the face zone is ventilated adequately but with considerably less air because little gas, dust, or fumes are present. The face excavating zone is sealed and maintained at slightly more negative pressure preventing dust and gas generating from within to escape. Explosive mixtures within the face zone is rendered non-explosive by the introduction of inert gas therein. Each zone is vented separately to the outside of the mine. Because less total quantity of air is required for human breathing, etc, the total ventilation system can be drastically reduced in tan capacity, development entries, and air shafts, -- a great savings in costs.

Jan 1, 1991

By CASSANDRA L. HOEBBEL, PATRICK L. YORIO, Emily J. Haas

This study revealed significantly less favorable perceptions of the existing organizational safety climate among workers in the underground coal-mining sector compared with those in the industrial-minerals and sand, stone and gravel (SSG) sectors. Consequently, it is important to consider pragmatic ways in which health and safety management systems (HSMS) in coal mines can alter processes to improve these perceptions. Given the interdependencies of safety climate factors and HSMS elements, researchers explored mineworker perceptions of the supportiveness of organizational safety climate factors among mineworkers and identified significant differences in perceptions across sectors. In this paper, we suggest that health and safety professionals in underground coal mining and organizations with fewer resources or less mature HSMSs focus on these factors to bolster support for proactive safety performance. Potential barriers to implementing or improving relevant HSMS elements and ideas to help foster more favorable perceptions of organizational safety climate are also discussed.

By Shailesh K. Patel, Shaaban Ben-Poorat

In order to ascertain the environmental fate of flotation reagents (fatty acids, fuel oils, and amines) associated with phosphate rock processing with confidence, it was necessary to first establish laboratory methodologies to identify and quantify flotation reagents. This approach was necessitated by the fact that the reagents used in the flotation process are either reclaimed or by-products of other industries and is dictated by their cost. Initially, several blind performance evaluation samples were prepared by spiking water samples with known amounts of either single reagents or reagent mixes and then analyzed. Reagent recovery for the blind performance evaluation samples was within acceptable limits for similar compounds established by the US Environmental Protection Agency. Averification process involving the use of standards and the refinement of analytical methods was utilized to develop standard operat- ing procedures (SOPS) and method detection limits (MDLs) specific to the identification and quantification of the flotation reagents used in the phosphate industry. These procedures and MDLs were critical to support the project's primary goal of assessing the fate of selected flotation reagents in the environment.

Jan 1, 1999

By Richard B. Jacob

The High Gradient Magnetic Separator (HGMS), also known as the High Gradient Magnetic Filter (HGMF), is an effective device utilized in magnetic separation. This method of separation is gaining popularity in the separation of sub-micron material containing feebly magnetics. The most common use of this type of separator is in the removal of iron stained particles to improve the brightness of kaolin clay. Potential areas for use of this magnet include: (1) desulfurization of coal (2) the clean-up of mill effluent (3) removal of fine particulate matter from municipal and industrial waste (4) desulfurization of oil

Jan 1, 1983

By Roy M. Fleming, Christine B. New

The federal standard for limiting exposures to miners from radon daughters was reduced from 12 working level months (WLM) per year to 4 WLM per year in 1971. However, even at that time some researchers were concerned that the new limit would eventually be shown to result in an excess risk for lung cancer mortality in miners. The National Institute for Occupational Safety and Health (NIOSH) is now engaged in a comprehensive review of this topic. As the lead agency in this project, NIOSH has developed a work plan and established a work group to implement this plan. The procedure and specific considerations are outlined in the work plan for developing a comprehensive ionizing radiation standard recommendation for all miners, underground and surface. Such a recommendation will not only include estimates of health risks at various levels of exposure, but also appropriate recommendations for medical monitoring, sampling and analytical methods, sampling strategies, posting, engineering controls, personal protective equipment and recordkeeping. The work group has twenty-four members. Eleven members are NIOSH personnel representing six divisions of the Institute. The remaining thirteen members represent other federal agencies, specifically the Bureau of Mines of the Department of the Interior, the Mine Safety and Health Administration and the Occupational Safety and Health Administration of the Department of Labor, the Office of Radiation Protection of the Environmental Protection Agency, and the Bureau of Radiological Health of the Food and Drug Administration, Department of Health and Human Services. Several factors contributed to the decision to initiate this project. First, the efficacy of the current standard was considered. An initial study group was formed in the spring of 1980 by NIOSH to identify and evaluate articles that contained information on lung cancer mortality risks at and below the present permissible exposure limit. The conclusion drawn from their evaluation was that a two-fold excess risk of lung cancer mortality at and below 120 cumulative working level months (CWLM) of exposure to radon daughters is evident. This composite indication from selected studies was of sufficient magnitude to justify further evaluation. The study group, however, recognized that other studies and information must also be considered in a quantitative risk assessment which would form the basis for recommending an acceptable and feasible permissible exposure limit. A second factor in the decision to pursue further evaluation was the gaps in the current standard that had previously been identified by the Mine Safety and Health Administration (MSHA). These included lack of medical monitoring of underground miners and absence of regulations for surface miners. The seriousness of the health hazard relative to other hazards in mining was also considered. Along with exposures to silica and asbestos fibers, radiation was judged to be one of the major health hazards in mining, These combined factors constituted the justification to develop criteria and recommendations for improved mandatory health standards. The development process begins with a survey and review of the available world-wide information on the topic, including data and information developed by NIOSH. The end product of this review is to be a document that will contain an evaluation of the collected information and support for any recommendations that are made. To develop this document, the present work group has been divided into five task groups with the following emphases: Health Effects, Medical Aspects, Monitoring, Environmental Exposures, and Engineering Controls and Work Practices. The Health Effects task group is to evaluate the evidence from epidemiologic and animal studies of adverse health effects associated with all forms of ionizing radiation encountered in mining and milling operations. The "weight-of-evidence" of the results of all relevant and useful studies will be summarized, with the reasons for emphasizing the cited studies. The critical cells or tissues and the factors that should be considered in estimating the dose to these areas from various types of radiation will be identified. An evaluation will be made of the possible impacts of smoking and exposure to diesel exhaust on the determination of health effects related to radiation. The implications of biologically redundant dose in terms of the time between tumor initiation and death will also be analyzed. The Medical Aspects task group is to review the generally-accepted and the state-of-the-art medical technology for the detection of adverse health effects from ionizing radiation exposure. An evaluation will be made of the accuracy of urine and fecal analysis, wholebody counting, chromosome analysis and nose blows, as well as their usefulness for early detection of adverse health effects. Early detection is of little utility to the affected individual unless subsequent medical care can improve the prognosis. Recommendations for screening tests will be made after carefully considering the accuracy of the diagnostic procedures and the usefulness of early detection. Required recordkeeping and transfer rights will also be addressed. The Monitoring task group is to consider the state-of-the-art technology for the monitoring of occupational radiation exposures. Instrumentation, sampling strategies and analytical procedures will be reviewed for both personal and area sampling. The implications of the associated levels of confidence for non-compliance decisions will be evaluated. The discussion will also include an evaluation of the feasibility of replacing present monitoring systems with recent technology and the impact that a possible lower permissible exposure limit would have on monitoring requirements. The Environmental Exposure task group is to investigate the field procedures and mathematical methodologies which have been used to quantitate exposure levels to the various kinds of ionizing radiation. The magnitude and direction of the possible biases in past exposure assessments will be estimated. Specific attention will be given to the controversies concerning the quantification of the biological dose equivalent and the feasibility of recommending standards for mixed radiation exposures which use "rem" as the unit of measurement. The Engineering Controls and Work Practices task group will analyze the advantages and limitations of

Jan 1, 1981

By Richard E. Hucko

The U.S. Department of Energy (DOE) Coal Preparation Program focuses on providing the technical and process-development basis that can be utilized to produce environmentally acceptable clean-coal feedstocks for use as market conditions permit. A major objective of the Coal Preparation Program is the development of physical coal-cleaning technologies capable of significant removal of mineral matter and pyritic sulfur at high energy recovery levels.

Jan 1, 1989

By Hu Wenjun, Li Maonan

Mine ventilation systems mostly are ventilation networks with fixed-quantity branches. The solution to the problem of ventilation networks with fixed-quantity branches is obtained by choosing the fixed quantity branches as chords and using Hardy Cross iteration method. The solution usually is feasible but may be not economical. This paper takes minimal annual ventilation electricity cost as an object, considering the power of main fans and boosters, natural ventilation pressures and resistances of regulators, and builds up a nonlinear programming model. A set of initial values of the nonlinear programming can be obtained by using Hardy Cross method, The MAP technique then used to find a set of local optimal solution The running procedure with a simple example is dicussed. Mine ventilation systems mostly are ventilation networks with fixed quantity branches. In the networks, air quantity of branches are generaly regulated by increasing branch resistance or air pressure. A comon approch to the of the networks with fixed quantity branches is to formulate it based on Kirchhoff's current and voltage laws and the solution is obtained by Hardy Cross iterative technique. The solution usualy is feasible but may be not economical. The optimal plan of air quntities regulation of mine ventilation network should be to make the solution satisfy both required quantity of work places and minimal ventilation operating cost. It is the purpose of this paper to introduce a new approch and computational experience of nonlinear programming of the optimal problem.

Jan 1, 1991

By Paul D. Tomlingson

Will Rogers unwittingly commented on the essence of evaluations when he said: "We don't know what they don't know!" In so doing, he explained why managers have an obligation to verify that their personnel really know what is expected of them. Rogers further stated that "What we know may not be so!" Here, he suggests that managers must establish the correctness of facts on which they make decisions concerning the future of their organizations. Yet, there are some managers who may not have considered this basic wisdom. These are perhaps the ones who shun a solid, fact-finding evaluation. Instead, they trust to guesswork as a basis for attempting improvement. Without realizing it, they may be making incorrect decisions harmful to the very organization they are trying to improve. Unfortunately, an attitude of avoiding evaluations often permeates whole organizations when their managers fail to appreciate their importance. Recently, the following was found prominently displayed in the office of a maintenance manager. Regrettably, the facts of a subsequent evaluation established how imprudent his attitude was:

Jan 1, 1991

By V. Montaruli, A. Nieto, M. Cardu

Nickel is a metal whose workability and mechanical strength at high temperatures and in corrosive environments makes it an indispensable alloying element for the realization of stainless steel, specialty steel, super-alloys, rechargeable batteries and electroplating. Because its main fields of application are key to the development of industry and, thus, to society, nickel has recently been recognized as a potentially critical mineral, despite its abundant reserves. The purpose of this paper is the creation of possible case scenarios determined by factors and events that, in the medium to long term, could change the current structure of the nickel market on the demand and/or the supply side. Four scenarios have been determined by considering a demand variation due to the occurrence of a natural disaster and an aerospace plan implementation and taking into account the resource nationalism and the skills shortage as supply varying factors. Through the creation of a georeferenced global nickel database, the paper proposes supply strategies related to the four scenarios for each top nickel consumer: China, India, European Union, United States and Japan.

Jan 1, 2013

By M. J. Gilbey

Cross passageways between adjacent tunnels in passenger rail or transit systems may be used during train fire emergencies to evacuate passengers to points of safety in the non-incident tunnel. Rescue trains can be brought into the non-incident tunnel to remove passengers to expedite evacuation times as compared to walking along bench walls to the nearest egress stairs. In cases of multiple train emergencies, the required ventilation capacities can result in high pressure differences between the incident and non-incident tunnels. These pressure differences can make it difficult or impossible for a normal person to open doors of a cross passageway between adjacent tunnels. If opened, the velocity of the airflow through an open cross passageway can reach levels high enough to impede passenger evacuation. This paper describes the analysis of this problem for a sample rail tunnel. A ventilation concept that mitigates the problems of high cross passageway door opening forces and high velocities through open cross passageways is presented.

Jan 1, 2009

A dedicated tunnel construction version of the Caterpillar 328D LCR compact radius excavator is proving highly productive on the A9 Autoroute construction project near Visp, in Switzerland. It is the first machine of its kind to operate on a Swiss contract and uses a special dedicated front attachment designed and constructed by German Caterpillar dealer Zeppelin. The machine offers a powerful, stable and compact solution for tunneling contractors. A rear overhang of just 305 mm (12 in.) provides a tail swing radius of just 1.9 m (6.2 ft). The 328D LCR is ideal for the restricted working areas within a tunnel construction site. The machine is equipped with the wide tracks from the 330D L conventional crawler excavator, ensuring maximum stability when operating. In addition, the boom mounting has been moved further toward the center of the machine for the tunnel model, creating an increased lift capacity over the front end compared with a standard 325D L. The boom itself features a robust box section construction, with high-strength steels, additional supporting struts and reinforced bearings for maximum durability. All pins have hard-chromium plating for optimum protection against wear. Stick digging force is a powerful 134 kN, with up to 212 kN of bucket digging force available, for maximum penetration in blasted material. The 328D LCR is also equipped with a heavy-duty dozer blade as standard. This ensures outstanding stability when working and providing a useful secondary tool for clearing and leveling within the jobsite. Two 45° tilting mechanisms in the boom construction, allow the boom to be swung to 45° on either side of the machine. So the specially designed attachment linkage provides increased rollback for access to the roof of the tunnel. A Caterpillar CW45S mechanical quick-coupler allows rapid changes between specialist tunneling attachments, standard Caterpillar buckets and a range of Caterpillar work tools. The machine is powered by a Caterpillar C7 diesel engine. This six-cylinder EU Stage IIIA diesel motor [ ] offers 8 percent more power than its predecessor, with 140 kW (190 hp) available at just 1,800 rpm. Caterpillar?s ACERT combustion technology results in lower fuel consumption and reduced exhaust emissions. However, the tunnel machine is also equipped with a diesel particulate filter as standard, to further cut exhaust gases within the tunnel working. The 328D LCR is designed for use in transport tunnels of 6.8 m (22.3 ft) in height. With the tunneling boom in place, the machine has an operating weight of 42,540 kg (93,783 lbs), yet retains a transport height with the tunnel boom of just 3.9 m (12.8 ft). Transport width with 600 mm (23.6 in.) track shoes, is just 3.2 m (10.5 ft). On the A9 tunnel contract, the machine is being used by a consortium of Swiss and Austrian companies working for the canton of Valais? Routes Nationals Construction (RNC) department. The 31.8-km (19.7-mile) A9 Autoroute construction project will connect Sierre in the west and the town of Brig to the east. The tunnel that is bypassing the town of Visp is just one of a number along the mountainous route.

Jan 1, 2009