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By David Caiden, Petros Fortsakis, Alan Hodgkinson

"1. INTRODUCTIONDo contractual practices affect project outcome? Can better contractual practices improve the likelihood of project success? The consensus amongst experts is that better contractual practices really do improve project outcomes. With this in mind the members of the International Tunnelling Association (ITA) Working Group 3 on Contractual Practices (WG3) pooled their collective knowledge to publish in 2011 the document entitled The ITA Contractual Framework Checklist for Subsurface Construction Contracts (ITA Working Group 3, 2011). Written for projects involving significant subsurface works, e.g. tunnels and caverns, the ITA Framework Checklist explains the major contractual issues that must be considered to ensure a successful project. Its goal is not to specify how each issue should be resolved, but rather to highlight the issues and give recommendations on how they should be addressed. The Checklist is compatible with, and provides guidance for reviewing, standard contracts such as FIDIC and NEC. One of the authors is a co-author of the Checklist and has contributed to previous papers describing the Checklist and its applicability to hydropower projects (Hodgkinson & Wilson 2014, Hodgkinson & Wilson 2015). The Checklist identifies a series of issues that should be contractually defined, which can be summarized as follows: •,Methods for dealing with geotechnical uncertainties should be defined in the contract •,There should be an appropriate level of geotechnical/geological investigation •,Sufficient mobilization periods should be allowed •,Sufficient time should be allowed for testing and commissioning •,Procedures for timely dispute resolution should clearly defined •,Quality and performance requirements should be clearly defined and measurable •,Provision should exist for cost consequences of unforeseen circumstances •,Dispute resolution processes should be clearly defined •,Payment processes should be fair and clearly defined •,Risk should be clearly allocated and parties should be able to bear the risks they carry •,There should be a mechanism for adjusting payments according to conditions •,The risk management approach should be clearly defined •,Admeasurement or unit price approaches are recommended •,The responsibilities of each party must be clearly defined •,The consequences of non-performance should be clearly defined •,The construction programme (schedule) should be realistic."

Jan 1, 2016

By Jianmin Qin, R. V. Ramani

The major parameters affecting dust flow at a longwall face are dust generation rate, air velocity and quantity distribution at the face, and the characteristics of the dust such as particle size distribution, density etc. Previous studies have identified the longwall shearer as the major source of the airborne dust in the faces. In this study, the effects of dust generation rate and shearer speed on the levels of ambient dust concentration are investigated. A series of experiments were performed under controlled conditions in a full scale simulated longwall face at the Lake Lynn Laboratory mine of U.S. Bureau of Mines using characterized bituminous coal dust. A trickle-duster was moved up and down the longwall face to simulate the shearer. In each experiment, a known amount of dust was dispersed by the trickle-duster into the air and the average dust generation rate was calculated. At the same time, gravimetric respirable and total airborne dust samples were collected and air velocity measurements were made along the face. The experimental conditions, data, and results are presented and discussed in this paper. The airborne dust concentration and air velocity data indicate that the concentration increases and air velocity decreases with distance from headgate for the first half of the face. Towards the tailgate, the air velocity increases with increasing distance but the dust concentration levels off with some variations. The data show that a higher dust generation rate results in higher dust concentration levels. More importantly, the data show that the rate of increase of airborne dust concentration is higher than that of dust generation rate. For the same air velocity distribution and dust generation rate, lower speed of the dust source results in higher airborne dust levels at the face.

Jan 1, 1991

By Terry McNulty

There are many potential pitfalls in the commercialization of innovative technology. The failures often are remembered longer than the successes, thereby serving as deterrents to subsequent attempts. The mineral industry's future depends on effective innovation. So it is essential that the causes of failure are understood. Innovation can be examined equally well in the context of geophysics, geology or mining. However the author's experience has been in mineral processing and chemical engineering. So the following discussion is limited to processes and/or plants for producing mineral concentrates, metals or inorganic chemicals. More of what follows has to do with underachievement or failure than success. But this article demonstrates that there is a strong element of predictability in the former. Furthermore, it is a credit to the minerals industry and to the engineering profession that a very high percentage of projects succeed in achieving design capacity and forecast operating costs. Innovation means the introduction of something new. In this article, the words "innovative technology" are used broadly. They include new processes and novel combinations of established unit operations, as well as novel types of processing equipment or largest-ever equipment models. The discussion of project outcomes is based on personal experience or on published information. Citations are given for technical publications that provide either project information or insights into the methodology used to analyze project performance. However, specific projects have not been identified due to the rather negative connotations of some of the conclusions drawn about the less favorable outcomes.

Jan 1, 1998

By Dong-mei Zhang, Feng Zhang, Hong-Wei Huang, Qiang Huang, Bin Ye

"1. INTRODUCTION Nowadays, many cities around the world have constructed metro tunnels to alleviate transportation pressure from rapid urbanization. In soft soil areas, metro tunnels are usually constructed by shield-tunneling method due to its high efficiency and little disturbance to environment. However, the tunnels may show significant post-construction settlement after several years of operation. Take Shanghai Metro line 2 for example, the maximum longitudinal settlement reached 160mm after ten years of operation, shown in Figure 1. When analyzing varying factors that contribute to the long-term settlement of tunnels, the effect of cyclic loading from train vibration is rarely taken into consideration for most researches only focus on the influence of leakage problems in the tunnel while neglecting train vibration induced leakage and resulting settlement. It’s true that metro tunnels from shield-tunneling method are prone to have leakage problems due to the special structural configuration. Furthermore, trains move hundreds of times inside the tunnel every day, which inevitably will cause accumulation and dissipation of excess pore pressure. When the excess pore pressure dissipates, tunnel settlement induced by train vibration occurs(Deng F H, 2007). Although researchers (Zheng et al., 2005; Wongsaroj et al., 2007; Mair, 2008; Shin et al., 2012; Zhang et al., 2012, 2015) conducted extensive numerical analysis on the relationship between tunnel settlement and relative permeability of tunnel to surrounding soil by treating tunnels as permeable media, their attention was only paid to the tunnel settlement from reduction of hydrostatic pressure in the ground, rather than from the dissipation of excess pore pressure generated by train vibration. Therefore, the influence of train vibration on the long-term settlements of metro tunnels is still not clear."

Jan 1, 2016

By Walter E. Jaworski, William R. Beloff, John Dunnicliff

As a step in the endeavor to reduce future tunneling costs in New York City, the Environmental Protection Administration, Dept. of Water Resources, instituted a program in 1972 to monitor the performance of the lining of one of its tunnels. A monitoring program was included as part of the contract specifications for the East Branch Interceptor Sewer tunnel for the Port Richmond Water Pollution Control Project in the hope that measured data would indicate possible future cost effective design or construction improvements. The monitoring program involved measuring ground deformations, circumferential liner stresses, longitudinal liner stresses, and jacking pressures. This paper presents some of the findings from these measurements, with emphasis on liner stresses. PROJECT DESCRIPTION The 3.05m (10 ft) diameter steel lined tunnel was constructed under two separate contracts. The easterly portion, Contract 3A, was approximately 3109m (10,200 ft) in length and constructed by Peter Kiewit Sons Co.1 The westerly portion, Contract 3B, was approximately 2160m (7100 ft) in length, and constructed by Richmond Constructors, a joint venture of Grow Tunneling Corp., MacLean Grove & Company, Inc., Grove, Shepherd. Wilson & Kruge, Inc., Morrison-Knudsen Company, Inc., and Andrew Catapano Co., Inc. Each contract included three test stations, hence a total of six along the tunnel route. Excavated material along the tunnel route consisted primarily of dense fine to coarse sand with varying percentages of gravel and silt with occasional boulders. Pockets of organic silt were encountered on Contract 3B and a large portion of Contract 3A ran through slightly weathered serpentine and schist. Overlying material and the groundwater level varied considerably along the route as did the height of overburden. Figures 1 and 2 show the generalized soil profiles for Contracts 3A (PK stations) and 3B (RC stations) respectively.

Jan 1, 1979

By F. Allen Meek

The Upshur Complex of Island Creek Coal Corp. consists of approximatly 35.000 acres of both surface and deep mine researves located in Upshur County West Virginia. The principle seams on the researve are the Middle and Lower Kittanning. Other mining in the area during the late 1960's and early 1970's produced surface mines that exhibited severely acidic drainage characteristics both during the mining phase, and after reclamation was completed. The Buckhannon River, the principal drainage for the area, is a high quality, lightly buffered stream, that is periodically stocked with trout. Because past mining had caused post mining acidic discharges and the Buckhannon River was a valuable recreational resource, mining permits for the area were put on hold by regulatory authorities, until solutions to the acid mine drainage questions could be addressed. In 1978, the director of the West Virginia Department of Natural Resources appointed a Task Force consisting of Industry, Regulatory. and Academlc participants. This Task Force was charged with gathering information and evaluating field procedures used during mining to prevent acidic mine drainage. In 1979, the group published a document titled "Suggested Guidelines for Mining in Potentially Acid Producing Overburdens" which summarized material handling and mining procedures that could be employed to help prevent the occurrence of post mining acid mine drainage. In 1982, a Technical Advisory Committee was appointed consisting of well known researchers in the field of acid mine drainage prediction and prevention. The group was charged with the task of conducting research in the field of acid mine drainage prevention. Mining conducted at the Upshur Complex between 1979 and 1986 employed various acid mine drainage preventative techniques recommended in the suggested guidelines manual and techniques concurrently being researched by the Technical Advisory Committee. Costs for the various techniques were documented and the resulting post-mining water monitored. The results of these evaluations are used by Island Creek in the planning of future mining operations in potentially acid prodcuing environments

Jan 1, 1991

By Omar Abd el Fattah Ramly, Abdallah Mohamed Sourour

FOREWORD In 1974, the Ministry of Housing and Reconstruction (The Client) which subsequently became the Ministry of Development and New Communities of the Government of the Arab Republic of Egypt assigned responsibility to the Arab Contractors (Osman Ahmed Osman and Company) for the design and construction of the tunnels under the Suez Canal. For this project the Arab Contractors of Cairo and Tarmac International of London formed a joint Venture, called Osmac. Sir William Halcrow and Partners of London are responsible for the design of the Ahmed Hamdi Tunnel as a Sub-Contractor to the Contractor. The advisory consultant of the client is a joint Venture between Tippetts-Abbett-McCarthy-Stratton (TAMS) of New York and Arab Consulting Engineers (ACE) of Cairo. INTRODUCTION A site investigation was carried out between Km 141 and Km 150 Suez Canal chainage to determine the ground conditions relevant to design and construction of a road tunnel under the Suez Canal. A feasibility study included aerial surveying, geological mapping and the drilling of 8 boreholes. Detailed investigation included the drilling of 105 boreholes, sampling, piezometer installation, pumping tests, and the digging of trial pits and trial excavations. In-situ work comprised SPT, permeability tests and dilatometer tests. Laboratory testing included soil classification tests, compaction tests, California Bearing Ratio tests, shear strength determination and oedometer consolidation tests as well as chemical analysis of both soil and ground water. The investigation revealed that the ground conditions at the first proposed El Shatt site (Km 148.5) were not favourable for bored tunnelling, whereas they were more favourable at the southern El Shatt site (Km 150.0).

Jan 1, 1979

By James D. Bennett, David L. Passmore

The Coal Mining Section of the National Safety Council has selected hand and finger injuries of coal miners as a major topic for safety policy analysis [Tinney, 19851. So that facts about hand and finger injuries can be used to guide the Committee's work and the work of policy-makers, we present in this paper detailed analyses of the following factors related to hand and finger injuries received by coal miners between 1975 and 1983: occupations of the injured miners; activities of the miners when injured; machines involved; objects, substances, exposures, or bodily motions that produced or inflicted the injuries; principal physical characteristics of injuries; and events directly resulting in the injuries. We analyze hand injuries for underground and surface mines separately because of the remarkably different production methods and hazards evident in these two operating environments. We do not, however, provide information about hand and finger injuries that occurred in surface operations at underground sites (such as yards, shops, or tipples), auger mining operations, culm banks, dredging operations, mill or preparation plants, offices, or laboratories. The most comprehensive information about the safety of coal mining in the United States is assembled by the Health and Safety Analysis Center (HSAC) of the Mine Safety and Health Administration of the United States Department of Labor. Mine operators in the United States report to HSAC all injuries as required under Part 50, Title 30, of the Code of Federal Regulations (mandated by Section 103 the Federal Mine Safety and Health Amendments Act of 1977, Public Law 95-164). These regulations stipulate that injuries must be reported within ten days of their occurrence on a United States government data collection form, Mine Accident, Illness and Injury Report (MSHA Form 7000-1). HSAC maintains these data primarily to produce federally-mandated reports. HSAC resolves injury reports that are incomplete, checks for errors in data coding and handling, and corrects inconsistencies in data submitted by

Jan 1, 1986

By John E. Tilton

Mining is one of the oldest human activities. It goes back at least to the Bronze Age and possibly even the Stone Age. The Romans mined copper in Spain and tin in England some 2,000 years ago. The writings of Agricola in the 16th century show that mining was important in the Middle Ages. Today, more mineral commodities are mined in greater tonnages than ever before. This long and fascinating history closely tied with the economic development of the human race is one of the charms of the mining industry. It also, unfortunately, gives rise to some widespread misconceptions. Old industries are generally considered stodgy with mature and stagnant technologies. Costs tend not to decline as in newer industries, and may even increase with real wages. Costs are particularly expected to rise in the case of mining as the best mineral deposits are depleted. Thus, mining is often thought of as a sunset industry, destined to decline over time as the resource base is depleted. These perceptions have several important implications. They argue against economic policies that rely too heavily on mining and mineral processing to foster growth and development. The best and the brightest young people, along with society's other valuable resources, should be encouraged to enter newer industries. There the technological opportunities and the prospects for growth are more promising. These perceptions also suggest that the ability to compete in the mining industry depends largely on the quality of a company's or country's mineral deposits. Mining will take place first in countries with the lowest-cost deposits. Once these are exhausted, mining will shift to countries with the next best deposits. From time to time, new discoveries may also produce a shift in the location of mining, [ ] and may even for a time keep the costs and prices of mineral products from rising. Over the longer term, however, rising costs and prices are inevitable, as the world is forced to exploit poorer mineral deposits.

Jan 1, 1997

By D. Lee Petersen, Charles R. Nelson, Marvin Marshak

INTRODUCTION Construction is underway on a laboratory cavern 713 m below surface at the Soudan Mine, Tower-Soudan State Park, in northeastern Minnesota. The 13.9 in wide by 11.6 m high by 71.8 in long cavern will provide a laboratory space for basic research in physics, in which experiments can be conducted with greatly reduced interference from cosmic radiation. A first generation experiment, called the Soudan 1 detector, is currently operating in a converted drift 591 in below surface at the mine. The initial phase of the Soudan 2 detector will be an 1100-metric ton unit, which will occupy approximately a 19 m length of the cavern. Control and monitoring equipment will be in a prefabricated shop office enclosure erected in the cavern. The location and planned usage for the laboratory cavern present special excavation, lining, and outfitting requirements. Temperature and humidity control, a relatively clean dust-free environment, and a long service life are required. Low cost and risk to the owner were basic requirements due to the nature of the funding. The most common type of site selected to meet these two constraints is either an operational mine or a civil works facility such as a road tunnel. There are often serious problems for such laboratories because of ongoing operations such as blasting, hauling, etc. Most of these problems do not exist for the Soudan 2 laboratory because the mine is used as a historical site with regular tours only in the summer season. The laboratory owner, the University of Minnesota, and the park owner, Minnesota Department of Natural Resources, are both public agencies of the

Jan 1, 1985

By S. D. Morrison, J. L. Watson

It is well known that the density and viscosity of a mill pulp have optimum levels for grinding efficiency, and sophisticated control loops are employed to control pulp density in industry. However, these control loops rely on a number of plant measurements, and often the input data will not permit effective determination and control of the mill pulp density. The use of a single remote pulp density measurement has obvious advantages, and it is suggested and demonstrated for laboratory batch grinding that mill noise measurements can indicate the effective density of the mill pulp. In addition, the mill noise is shown to indicate the actual effective pulp viscosity in the mill and hence permit the identification of the dynamic rheological regime existing in the mill. It is demonstrated that mill noise increases with grind time and, at any given grind time, with increasing pulp density in the pseudoplastic range. This increase in mill noise level with pulp density is interpreted as indicating a decreasing pulp viscosity. The results show that the transition from dilatant to pseudoplastic conditions within the mill, with increasing pulp density, can be identified by this increase in mill noise. When the pseudoplastic pulp started to exhibit yield characteris- tics, the mill noise fell dramatically. The technique of mill noise analysis is then used to investigate the effect of a grinding additive on the batch grinding of two ores. With a magnetite ore, the additive was shown to increase the mill noise, and hence decrease the pulp viscosity, in the pseudoplastic region and to increase the effective grinding. The molybdenite ore, however, did not show significant noise level changes and did not show improved grinding efficiency.

Jan 1, 1987

By K. Adam

The sustainable management of solid wastes, including the wastes emanating from portable batteries, consists one of the main objectives of the current EU Environment Framework Programme. Overall reduction in the quantity and volume of disposed wastes, elimination of dangerous species within the waste streams and wastes recycling comprise specific targets of this policy. Within this framework a Greek funded research project entitled ?Development of an Integrated Alternative System for the Environmentally compatible Management of Used Batteries and Accumulators - DIASBAT?, was recently completed by a research team consisting of major Greek Battery producers and retailers, Research Organisations, Universities and Environmental Consultants. The aim of the project was the development of an Efficient Alternative Management System for spent portable Batteries and Accumulators, (B&A), in compliance with the prevailing EU and national environmental legislation, taking advantage of the state-of the art technology. The present article summarises the research carried out within the DIASBAT project in order to review and develop a set of sustainability indicators for the assessment of the effectiveness of Spent Portable Batteries Management Systems (SPBMS). Based on the European experience and practice, various indicators were initially examined regarding the performance evaluation of SPBMS. Specifically, the indicators used in European studies conducted to assess the environmental, social and economic impacts of the recently issued Batteries Directive 2006/66/EC, as well as the indicators used by European Collection and Recycling Organisations (CROs) to assess the performance of SBPMS across Europe were presented and analyzed. Additionally, the set of indicators used within DIASBAT to assess the effectiveness of alternative Spent Portable Batteries Collection Schemes developed within the project, are presented. The experimental collection networks of the DIASBAT project included schools, selected retail stores and a pilot network set up by the Greek Institute of Geology and Mineral Exploration (IGME). From the evaluation of the various indicators, it was deduced that in order to assess an Integrated Spent Portable Batteries Alternative Management System, a multi criteria analysis approach is required. Within the general principles of sustainable development, there is a need for different qualitative and quantitative indicators to be combined, taking into consideration critical parameters such as: annual portable batteries collection rates, compliance with the targets set up by the prevailing European and national legislation, economic performance of the System - and finally social criteria - environmental sensitization according to age, gender, economic prosperity, educational level etc.

Jan 1, 2007

By James I. Mathis

Should an arbitrary reduction factor be applied to laboratory compressive strengths when designing pillars? The answer is, as is the main contention of Peng's article, probably not. Many factors affect the strength of the material remaining in the pillar. On the other hand, outside influences will influence the strength testing results from the lab. This is not the first article, nor the last, to discuss the discrepancy between the two strengths. As was discussed in the article, actual pillar strength is affected by several factors. The two mentioned were: • The scale effect of discontinuities. How large must the pillar be so that the increase in discontinuity count with size will not decrease the strength. • Non-uniform strengths and lithologic units within the pillar. The scale effect of discontinuities is important. What size block must be tested so that the rock mass strength is actually measured? For a highly fractured rock mass, or coal with a high cleat density, this sample may be quite small. Conversely, if an unaltered, moderately jointed, quartz monzonite was examined, the sample block would likely be very large. This is the subject of ongo¬ing research. More to the point, if the tested sample is sufficiently large to model the rock mass strength, then no reductions should be made in the lab strength based on this factor alone. Non-uniform strengths and variations in lithologic units will also affect the pillar strength. I am not an expert in coal mines, having gained my experience in hard rock metal mining. These problems, though, are commonplace. However, strength sampling for pillar strength determination involves sampling material from within the lithologic unit that will form the pillar, not from pieces of material found on the floor. In addition, this sampling should cover the entire range of strengths of the material in the pillar-hard units (such as the partings described by Peng), as well as soft units. Testing results should then be included in the pillar design. Contrary to statements in Peng's article, at least one rock mass rating system (Laubscher, 1990) allows for the compositing of strong and weak units into a design rock mass strength that can be used for pillar design.

Jan 1, 1993

By Paulo Roberto Pereira

This paper is motivated by the belief that increasing drilling and blasting costs will not necessarily bring about better digging or crushing productivity. As a matter of fact it can be counter productive as the ensuing discussion will show. In the two case studies presented herein when powder factor increased, productivity at a rope shovel and at a primary crusher decreased. Experience has shown that equipment (shovel and primary crusher) productivity increases as the powder factor increases and concurrently operating costs decrease. This is illustrated by Figure 1where the graph shows (assuming drilling costs constant) that for increases in powder factor initially operating costs might fall till a certain point and then they start to go up again. By the same token we need to understand what is the behavior of the operation’s productivity. It seems intuitive productivity goes up for increases in powder factor but when an operation reaches the point of minimum operating cost one could say that productivity reached its maximum. For continuing increases in powder factor can productivity still go up or does it go down? This paper presents two examples where the productivities of a surface coal mine and of a quarry are reduced for increases in powder factor. This indicates that these two operations could be operating to the right of their minimum operating costs and maximum productivity and therefore wasting precious drilling and blasting dollars and resources. Moreover, their productivity is following the red dotted line in Figure 1 and the question becomes can they follow the blue dotted line for increased drilling and blasting costs? The industry owes to itself to determine this minimum operating cost point and what can be done in case that the productivity goes down afterwards despite an increase in drilling and blasting costs. In other words, utilize your drilling and blasting resources correctly. In the two examples that follow single explosive loading strategies make powder factor a valid means of comparing the results of productivity as a function of powder factor. Also, external factors such as equipment operator influence are eliminated due to the long time span considered in the analysis

Jan 1, 2005

By Lawrence W. Teufel

Knowledge of in situ stress and natural fracture distribution at depth improves our ability to stimulate and produce low permeability reservoirs. The focus of this study is three closely spaced, 2.5 km deep vertical wells in the Piceance Basin of Colorado. The wells were completed through the tight lenticular and blanket gas sands of the Mesaverde Group. In situ stress directions and magnitudes were determined from hydraulic fracture tests and anelastic strain recovery measurements of oriented core. The distribution, orientation, and characteristics of natural fractures in the subsurface were determined from detailed observations of over 1300 m of core, of which 400 m was oriented. Stress measurements clearly show that horizontal stresses are strongly influenced by lithology. In a sandstone/shale sequence at a depth of about 2.0 km in situ stresses in sandstone formations are anisotropic, with the average ratios of the minimum and maximum horizontal stresses to the overburden stress being 0.82 and 0.96, respectively. In sharp contrast bounding shale formations are lithostatic. This stress contrast between sandstones and bounding shale formations could act as a barrier to hydraulic fracture propagation during stimulation and impede vertical fracture growth. Natural calcite-filled fractures are present in over 7 percent of the core, with several horizons having a much higher frequency of fractures. Fractures are found primarily in sandstone. The fractures have a strong preferred orientation of N 1060E[+]110, which is aligned with the maximum horizontal stress and direction of hydraulic fracture propagation. The interaction between a well developed fracture fabric and anisotropic stresses in sandstone formations produces a permeability anisotropy, with the maximum permeability aligned with the fracture fabric and maximum horizontal stress.

Jan 1, 1986

By Robert A. Jankowski, Fred N. Kissell

Recent allegations about tampering of coal mine dust samples have led to suggestions that the coal industry needs a respirable dust compliance sampling method that is less subject to tampering. The sampler designs under consideration include fixed location monitors that could be mounted on a mining machine or located at a stationary location in the mine, and samplers that are worn, like the existing samplers. Fixed-point samplers have a design advantage, since samplers worn on the body will have size and weight limitations. On the other hand, in some cases there are respirable dust concentration gradients, which will dictate careful placement of a fixed-point sampler inlet to determine the exposure of workers. This study examined dust concentration-gradient data obtained by the Bureau of Mines and others over the last decade. As an example of spatial gradients at continuous miners, a fixed-point monitor located in front of the operators cab shows a higher dust concentration than a sampler located on the operator and reduced exposure when the sampling location is behind the operator cab. It may be necessary to use a sampling tube with a machine mounted monitor, to sample in the operators breathing zone in the cab to provide a more representative sample of the miners exposure. For face workers on longwalls or on continuous miner sections using remote control, the study shows significant dust level gradients and gradient variations between typical operator positions and mining machine locations. In addition, if fixed-point monitoring is used to monitor an area, vs the exposure of specific workers, dust control technologies currently employed to ensure reduced dust exposure such as the diversion of dust laden air away from the workers, or through the use of remote control of mining machinery may not indicate the same dust reduction obtained with current sampling techniques.

Jan 1, 1993

By Lynn B. Hales, Randy A. Ynchausti

Introduction There continues to be a large economic opportunity associated with improving process performance through advanced process control systems within the minerals industry. The basis for this opportunity lies in the inherently low efficiencies of many of the unit operations found in mineral processing plants as well as the continual variation that is present in the ores being processed. The ageless target of such control systems is improved recoveries and concentrate grades, higher processing rates and lower unit costs. Many plants are enjoying the benefits of modem, well functioning process control systems but few if any have achieved plant-wide optimization in an economical sense. As new process modeling and control technologies, such as neural networks, continue to evolve and develop, the potential for plant- wide optimization is becoming a closer reality. Neural network technology appears to have a significant potential in the general field of process control and control of mineral processing operations. Neural networks are an emerging technology that have been evolving out of the study of biological systems since the early 1940's. The first software simulation of neural computing networks was reported in 1956 by Nathanial Rochester of IBM Research during the first conference on artificial intelligence which was sponsored by the Rockefeller Foundation. Neural Networks Neural networks can be considered to be a class of computer program that perform their problem solving functions based on a rudimentary model of the human brain and how it solves problems. Traditional computer programs and even computers themselves solve problems or process data sequentially and in a deterministic manner. The human brain, on the other hand, processes data and solves problems in a massively parallel fashion. We think of computers normally in terms of having a single processing unit, sometimes a co-processor to assist in certain activities such as mathematical functions or communications, bytes of memory, processing speed and program/data storage size.

Jan 1, 1992

By Zhongxue Li, Wenguang Li, Yiqing Zhao, Shuaiqi Wang

"Faced with the serious managerial situations and diverse conditions and needs for mine safety, occupational health and environmental stewardship in Chinese mining communities, an evidence-based approach is proposed for the management of mine safety, health and environment integrity. By the proposed approach, tangible and effective scientific evidence should be collected and accumulated, and the authenticity, accuracy and applicability of the evidence should be assessed to form an evidence-based approach for characterizing mine safety, health and environmental hazards and risks from multidimensional perspectives. The results are then used to formulate diverse safety, health and environment functional requirements. In an evidence-based approach, the evidence is combined with the professional experiences and the actual economic and technological situations, availability and affordability of a mine. This approach is helpful to establish scientific, reasonable, acceptable and effective solutions for identifying and mitigating hazards and improving the level of mine safety, health and environment integrity of mining operations.Introduction / Background In recent years, economic reforms have opened China's economy so that Chinese society has rapidly modernized. Along with this advancement, the exploitation and utilization of mineral resources continues to be active and the scale of mining production continues to increase, which has created a deterioration in resource reserves and as well as the general condition of mining technology. There are many hazards and safety problems in mine production and occupational health as well as in the community environment in China’s mining industry. These problems threaten the security of China's mines and present serious obstacles and challenges to the industry and the government. According to the statistics from the State Administration of Work Safety Supervision, there were 50,500 mine safety incidents in China between 2001 and 2013, which consisted of 31,439 coal mine safety accidents and 19,061 non-coal mine safety accidents, resulting in 30 deaths (Qin 2014). At the same time, mineral dust and radioactive material from mine production processes have increased the morbidity rate of silicosis and cancer in mining workers."

Jan 1, 2017

By Ralph H. Knode, Stephen P. Collings

INTRODUCTION The Crow Butte uranium deposit is located in northwest Nebraska near the town of Crawford (Figure 1). The deposit was discovered during the fall of 1980 by Wyoming Fuel Company, operator of the Crow Butte Joint Venture. The Crow Butte Joint Venture is owned 50 percent by Wyoming Fuel Company, a subsidiary of KN Energy, Inc.; formerly Kansas-Nebraska Natural Gas Company, Inc., 40 percent by Ferret Exploration Company, Inc., and 10 percent by First Exploration Company. A preliminary announcement made in January 1981 indicated a "probable potential" reserve in excess of 25,000, 000 pounds U303. Drilling during 1981 and 1982 confirmed these reserves and indicated the presence of more than 30,000,000 pounds U308 having an average grade in excess of 0.25 percent U308. Wyoming Fuel Company was initially attracted to the area in 1978 by favorable regional geology for sandstone uranium deposits and weak radioactivity noted in regional oil and gas holes. Exploration drilling began in 1979 following the formation of the Crow 3utte Joint Venture. Drilling has continued up to the present, at which time the Joint Venture is ready to proceed with a pilot scale solution mine. Environmental baseline data have been acquired and the permit applications for the pilot scale mine have been submitted to the Nuclear Regulatory Commission and to the applicable state agencies in Nebraska.

Jan 1, 1984

By A. R. Wagner, E. Berkman

The use of high-resolution seismic surveys in coal exploration and mine development is becoming established as a standard technique in the industry. Their most significant contribution is in the effectiveness of reducing the number of core holes needed to understand the complex geological nature of coal by identifying geologic faults and mapping coal seam continuity and relative coal thickness. With these goals in mind, a high-resolution seismic survey was conducted in 1980 in the Wasatch Plateau coalfield of Utah. As a result of the success of this initial survey, numerous additional surveys have been performed over the past six years.. The interpretations of these subsequent surveys have led to the location of faults, fluvial channel sandstones, and coal thickness trends. This paper presents a review of high-resolution seismic technology as applied to coal exploration followed by three case histories, two of which illustrate the utility of the technique related to coal thickness determination and faulting and one that serves as an example of pitfalls in interpretation.

Jan 1, 1987