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By David A. Grisafe

Divided opinions concerning dredging-permit locations and boating uses on the Kansas River in northeastern Kansas led to a study of the recreation potential on the river by a legislatively mandated interagency group (five agencies) that included the Kansas Geological Survey (KGS). In addition, the KGS conducted its own study of the river corridor, encompassing the development, geology, and economic resources of the corridor (Brady and others, 1998). The corridor area is 12 mi wide and 140 mi long (171 river miles). Included in the study was the potential impact of restric¬tions to river dredging. The Kansas River and its floodplain in northeastern Kansas are underlain by Lower Permian and Upper Pennsylvanian limestones and shales. The river and its floodplain are the major sources of sand and gravel for northeastern Kansas, and the limestones along the river bluffs supply crushed stone and building stone. The population of the 10-county area bordering the river has grown by 20% since 1980, and now comprises nearly 40% of the state's population (U.S. Bureau of the Census, 1996). Projections (Floerchinger, 1992) indicate close to 50% of the Kansas population will reside in these counties by 2025, with a continued increase in the demand for aggregates. Factors such as floodplain width, price and availability of land, and overburden ratios tend to favor river dredging on the lower part of the river, and floodplain or pit dredging on the upper portion. The use of alternate sources of sand and gravel such as the Missouri and Arkansas Rivers would increase sand prices due to transportation costs to much of the 10-county area. In 1996, river and pit dredges along the Kansas River supplied more than 3 million tons of sand and gravel valued at about $8 million to northeastern Kansas. As a result of its study, the KGS had concerns with the idea of large recreation zones on the river that excluded river dredging in areas of presently large population and projected population growth. This controversial issue is likely to recur elsewhere.

Jan 1, 1999

By M. P. Evans, Rainer Kahrger

During the last decade or so great advances were made in the solvent extraction, electro winning technologies. They, combined with heap leaching, made it viable to exploit large, relatively low grade oxide copper deposits. The El Abra mine is a good example for such a deposit. Situated in Northern Chile at an elevation of about 4000m (14000 feet), 70 krn north of Calama, the El Abra deposit has been known for many years. In the early 1990's Codelco decided to sell a major holding in the deposit to international mining companies. After lengthy negotiations Cyprus Minerals finalized in June 1994 the purchase of 51% of the deposit with Codelco retaining the balance. lance. Already in 1993 Cyprus and the engineer on the project, began discussions with international materials handling companies with regards to the materials handling system required for the project. These early discussions were considered critical for this fast track project. Immediately after the notice to proceed with the project, several companies were invited to submit competitive conceptual proposals for that portion of the material handling system which was to transport crushed and treated ore from the plant to the leach pad and build the leaching heaps at a rate of up to 150 000 tons per day. A supplier was selected. Additional studies were made for the conveyor system from the mine to the fine crushing plant. Due to the extremely rugged terrain and high altitude at the mine, a decision was made to locate the plant and the leaching operations 15 km east of the mine at an elevation of 3400m. In July 1994 the supplier started the conceptual engineering with a design team at the engineer's San Francisco office. The undertaking was unique in the sense that the supplier's engineering team was integrated into the project for the duration of the conceptual engineering. The open and continuous communication greatly contributed to the success of the design work.

Jan 1, 1996

By W. A. Cincilla, S. C. Tadolini

INTRODUCTION Resin bolting systems continue to gain popularity in underground coal mines in the United States, and their general success under a wide range of geological and operational conditions is well documented. In 1984, 36% of all bolts used were resin-grouted systems. However, many questions dealing with basic support mechanisms and the influence of various factors on bolt effectiveness in situ remain only partially answered. The Bureau of Mines' Denver Research Center conducted a major research project to investigate the influence of installation procedures on the effectiveness of resin-grouted roof bolts. The project consisted of two main studies: the first dealing with the contribution of bearing plates to the load-carrying capability of the bolt; the second examining the relationship between installed grout column and the anchorage capacity as measured by the standard pull-out test. Additionally, a finite-element computer model and other analytical and empirical techniques were applied to aid in the basic understanding of the test procedures and to examine the load transfer mechanism in resin-grouted bolts, which to date has not been comprehensively assessed. The plate study includes field test results from two mines (Fig. 1). At these test sites two behavioral parameters were measured: the actual loads that bearing plates were subjected to when installed in conjunction with full-column resin grouted bolts, and the roof movements generated by the applied loads. Results indicate that bearing plates are subjected to varying degrees of loading, which range from conventional installation pressures of 2.2 kN (500 lb), up to a measured load of 142.4 kN (32,000 lb) when the immediate roof is shifting and deforming. These measured loads indicate that the bearing plate is an integral part of the support system. Differential sag stations, installed to monitor roof displacements in the test sites, show the highest degrees of loading occur in conjunction with the largest amounts of movement. The column-length study addresses possible reductions in anchorage capacity of "full column" bolts. These reductions could result from such factors as the loss of grout to surrounding strata, or improper mixing of catalyst and resin. Field test sites were established at eleven mines located in major coal mining districts throughout the United States (Fig. 1). Four major roof-rock types were represented in the study: shale,

Jan 1, 1986

By S. G. Vick, K. E. Robinson, W. D. Webb

INTRODUCTION This paper discusses two uranium tailings waste disposal studies that reflect the United States Nuclear Regulatory Commission (NRC) regulatory actions and their changing requirements during the mid to late 1970's. Present guidelines require that all new uranium tailings impoundments be designed and constructed to eliminate, to the extent that it is reasonably achievable, exposures and risks to the public from the tailings. This includes positive measures for control of seepage losses from the impoundment and for control of radiological releases caused by wind and water erosion. Long-term stability of the reclaimed impoundment is also a very important requirement. That is, it is intended that the tailings impoundment, once it is reclaimed, will require little or no care or maintenance as long as the uranium tailings remain a hazard. Principally because of the long-term stability objective, the NRC has now identified subsurface burial of the tailings as the "prime option" for tailings disposal. The environmental implications of these proposed regulatory actions are obviously desirable. The economic implications the actions may have on a particular project are not always so obvious because they are so dependent on environmental suitability of site conditions. Selection of a site with favorable topographic, geologic and hydrologic conditions will usually result in the most economically and environmentally attractive alternative for tailings disposal. The first project discussed in this paper was initiated before the NRC guidelines had been developed to favour subsurface burial. At the beginning, seepage and radon emission control requirements were moderate. Constraints were imposed on the design by site topography, geology, and project capitalization considerations, factors which were dealt with according to straightforward engineering and design principles. More serious constraints were imposed by changing regulatory requirements. Unlike the more usual engineeringrelated constraints, regulatory requirements were upgraded during the design process, causing the design itself to undergo numerous modifications. The second project was initiated after the NRC proposed regulations had become better defined and below grade burial appeared to be the preferred

Jan 1, 1980

By Daniel Hodouin, Claude Bazin, Sami Makni

SCOTT COULTER: Thanks, Eric. Thank you all for coming. Our first speaker today is Claude Bazin. Claude received a degree in metallurgical engineering in 1980 from Laval University in Quebec. He worked for a short time in a mineral processing plant and then returned to Laval to complete graduate studies in the field of process modeling and control. He obtained his master's degree in 1983 and his Ph.D. in 1990. In 1987 he joined Brunswick Mining, New Brunswick, as research metallurgist and subsequently process control engineer. In 1990 he joined Helzfield Mines, New Brunswick, as senior metallurgist. In 1991 he accepted a position of professor at the department of mining and metallurgy at Laval University, a position he is still holding. He's a member of the CIM, TMS, and the Society for Mining, Metallurgy, and Exploration. Claude's topic today is "On-Line Material Balance for Flotation Plants." INTRODUCTION CLAUDE BAZIN: During the last two decades, the on-stream analyzer (OSA) has gained the stat& of key instrument for the control of flotation plants. The OSA is currently used in almost every sulphide flotation plant (Leroux and Franklin 1994), and its application to oxide mineral flotation plants is increasing. The OSA assays are sent to the flotation operators via an operator console or to control loops of various degrees of complexity (McKee 1991) implemented in a distributed control system (DCS). Operators and/or controllers take control actions based on these assays to ensure an adequate operation of the plant. Although this application pays off very rapidly for the purchase of the OSA, one could ask, "Could we get more from the OSA?" Some plants reported the use of OSA measurements for process optimization (McKee 1991). The optimization strategy is based upon economic indices calculated from metal recovery using the 2-product formula (Wills 1992, p. 124). The 2-product formula is sensitive to measurement errors in the assays and can lead to considerable scatter in the calculated indices (Hodouin et al. 1993). Least squares algorithms provide a robust alternative to filter out measurement errors (Spring 1992). This paper presents some applications of a recursive least squares algorithm that provides real-time estimates of the mass flow rates within a flotation plant using OSA and mass flow rate measurements.

Jan 1, 1998

By Rong Guo, Qi He, Jinsuo Zhang

"Coal mine ranks No.1 among the 6 major high-risk industries, so it is no doubt that the senior managers in the coal mine bear more stress than other industry executives. The massive working stress results in serious influences on the physical and mental health of the senior managers of coal mine, which might also induce the safety risk in the coal mine. Therefore, to evaluate the senior managers’ working stress and put forward strategies of mitigating the stress is of great theoretical and practical significance in improving the physical and mental health of the senior managers and reducing the safety risk in the coal mine. The research on the working stress has been made in the western countries for almost 50 years, China began the research in the mid and late 1990s, the research is spread across multiple industries including education, medical treatment, computer and aviation. However, there is little research on the senior managers’ working stress of the coal mine, so the available literatures are few. In the paper, we, based on the working stress model of Robbins and through questionnaire survey, analyze the element composition of the senior managers’ working stress of the coal mine; then, we construct the evaluation indicator system of the senior managers’ working stress of the coal mine based on the individual factor, organization factor and environment factor; after that, we determine weights of each evaluation indicators by using the improved triangular fuzzy number weight method, and set up the evaluation model of the senior managers’ working stress of the coal mine on the basis of the fuzzy comprehensive assessment method. At last, in accordance with the model, we evaluate and analyze the working stress for the senior managers of some typical coal mines, and diagnoses the major sources and intensities of the senior managers’ working stress, and then propose corresponding strategies of mitigating the stress."

Jan 1, 2017

By Carlos A. Jaramillo, Seng Hing Ngu

"The Murum Hydroelectric Project is a 944-MW development consisting of a 145 meter high RCC dam, two 2660 meter long, 9 meter excavated diameter upper pressure tunnels, surge shafts, two 950 meter long 7 even meter OD penstock tunnels and a surface powerhouse. The project is located in the eastern section of the State of Sarawak, Malaysia, about 200 kilometer from Bintulu, in the Rajang Fold-Thrust Belt, an Upper Cretaceous to Upper Eocene fold and thrust belt that extends under most of Sarawak. The Belaga Formation consists of a thick sequence of deep marine sediments currently appearing as steeply dipping strata of thin to thick bedded, fine to medium grained sandstone interbedded with argillaceous rocks, resulting on a “Flysch” type geologic environment. The project pressure tunnels were excavated perpendicularly to these strata resulting on frequent change on rock conditions and behavior, and required rock support. This paper describes the characterization of the rock mass, design of rock support, and incidents during construction. Particularly interesting were convergence issues in Tunnel 1 resulting from Tunnel 2 excavation. INTRODUCTION The Murum Hydroelectric Project is located in the eastern section of the State of Sarawak, Malaysia, about 200 kilometers from Bintulu, and upstream of the Bakun Hydroelectric Project. The project consists of a 145 meter high RCC dam, a 50 meter high intake tower, two nine meter OD and 2660 meter long upper pressure tunnels, two nine meter OD and 175 meter long vertical shafts, two 25 meter diameter and 80 meter deep surge tanks, two seven meter OD and 950 meter long penstock tunnels and four seven meter OD and 50 meter long branch tunnels, two 8 meter diameter to 3.4 meter diameter and 1400 meter long penstocks installed within the shafts, penstock tunnels and branch tunnels ending in a powerhouse with 944 MW installed capacity. LAYOUT OF THE WATERWAY TUNNELS The two waterways tunnels are basically parallel as shown in Figure 1, with each tunnel supplying water to two units in the powerhouse. The tunnels start separated 25 meters center to center, but 250 meter from the intake the separation increases to 35 meters. The tunnels are lined with reinforced concrete until they reach the surge shafts and steel lined from there to the powerhouse. The tunnel profile is shown in Figure 2."

Jan 1, 2016

By Laura J. Carroll, Gordon A. Goldsmith

Experts, like many of the speakers at the SME Annual Conference, are frequently called upon by lawyers to assist them in litigation. Due to the technical nature of many cases, the testimony of an expert with knowledge and experience in a particular field is necessary to help a judge or jury understand and decide certain issues. Environmental litigation is no exception. Experts routinely are called upon to offer testimony to establish the existence of contamination and its source, as well as the potential health and environmental risks associated with the contaminants. This article will briefly discuss the factors courts apply to determine whether to admit expert testimony after the recent Supreme Court decision in Daubert v. Memell Dow Pharm., Inc., 509 U.S. 579 (1993). The Court's decision in Daubert overruled a long-standing test that had based the admissibility of scientific evidence on its "general acceptance" in the field in issue. Next, the article will discuss in general terms what a party must do to "link a particular defendant's conduct to the contamination involved in order to recover from that defendant. This link, known as causation, varies depending upon the type of claim being asserted. Expert witnesses are used extensively to help establish causation. JUNK SCIENCE OR GOOD SCIENCE- HOW DOES A COURT DETERMINE WHAT TO LET IN A frequent complaint in litigation involving technical or scientific issues is that one party or another is trying to use so-called "junk science" to prove its case. While some expert testimony might be so clearly lacking in support or so "off the wall" that a court can easily determine to exclude it, other testimony, especially testimony on the "cutting edge," is much more problematic. In 1923, the District of Columbia Circuit Court of Appeals decided the case of Frye v. United States, 293 E 1013 (1923). In deciding whether to admit certain expert testimony, the court in Frye stated that while a court will "go a long way in admitting expert testimony deduced from a well-recognized scientific

Jan 1, 1998

By J. E. Powell

Introduction The disposal of mine tailings, development rock, and other unwanted refuse material underground in mines by using pneumatic conveying techniques has been undertaken in the coal industry for many years. Similar equipment has been utilized for backfilling hard rock mines and is currently being applied in a gold mine in South Africa where development rock is being stowed in the mined-out stopes to help reduce the incidence of rock outbursts. On a limited scale, pneumatic conveying has been applied for backfilling uranium mines and one particular mine in New Mexico, U.S.A., has used this technique for 8 years. Other uranium mines in this area are now considerinq the dry backfill technique to eliminate the problems associated with hydraulic fill. The need to backfill in uranium mines is primarily of importance to improve ventilation, stabilize the pillars and roof, and possibly to extract a larger percentage of the uranium ore. If this can be achieved by utilizing the tailings from the beneficiation plant and using rock from the development headings which in itself may be slightly radioactive, then a greater benefit can be derived. Backfill can be achieved with hydraulic fill methods by running slurry into the stopes and allowing the water to decant and return through the footwall development entries to sumps for pumping to the surface. However there are several disadvantages associated with this method in that water is percolating throough the mine workings; it is necessary to build bulk heads in flat lying deposits; it is difficult to fill right to the back; and the decanted water takes with it quantities of the finer sand particles which results in maintenance problems with the mine pumps. Pneumatic conveying can overcome these problems in that the voids can be completely filled with high degree of compaction, heavy bulk heads are not necessary, the development rock can be added to the pneumatic system for disposal underground so eliminating hoisting cost to the surface, and cement can be added to the wetted material. To

Jan 1, 1980

By D. Tao

Coal is a major source of energy in the U.S. and more than 51% of the electricity used in the country is generated from coal. Coal cleaning prior to combustion is necessary and often accomplished using wet physical processes at coal preparation plants to remove impurities such as ash, sulfur, mercury. However, the resultant clean coal product still contains a significant amount of impurity due to the fact that impurities are not well liberated from coal particles ranging from several millimeters to inches in size at which wet cleaning processes take place. A cleaner coal product can be obtained if a cost-effective dry process is developed to further clean pulverized and thus better liberated fine coal at the power plants prior to its combustion. The benefit of such a process is a significant reduction in the cost of expensive post-combustion chemical cleaning processes such as flue gas scrubbing employed to meet the stringent environmental air quality regulations. In this study, a novel rotary triboelectrostatic separator (RTS) was investigated for its application to dry cleaning of fine coal samples acquired from the power plants in the state of Illinois. The pulverized fine coal contains well liberated ash and pyrite minerals and is an ideal feed to the triboelectrostatic separator for further cleaning without the use of water or any chemical reagents. The proprietary rotary triboelectrostatic separator (RTS) is characterized by an innovative high efficiency rotary charger, charger electrification, laminar air flow, and specially designed electrodes. Compared to existing triboelectrostatic separators, the rotary triboelectrostatic separator offers significant advantages in particle charging efficiency, solids throughput, separation efficiency, applicable particle size range, etc. Testing with several fine coal samples has demonstrated that this technology can significantly reduce ash content with a process efficiency similar to or better than froth flotation. Important process parameters such as charger rotation speed, injection and co-flow rate, feed rate were investigated for their effects on separation performance.

Jan 1, 2010

By Pooyan Asadollahi, Praveen Krishna, Michael Joye

"Durability design for underground structures is an increasing focus of designers and owners in the underground construction industry. Many owners have expanded their requirements for durability design, with specific requirements for structure lifecycle and designer certification of structural durability. This paper describes current trends and best practices including: defining the underground structure lifecycle, historically durable underground structures, design methods for underground structure durability built of reinforced concrete, and durability of materials. Criteria to be used for defining end of structure life and owner’s maintenance responsibilities are crucial to lifecycle contract requirements. Current practices of several major owners are presented. Design methods are presented including United States code requirements. Current best practices for enhancing the durability of materials used in underground construction are discussed including: low permeability concrete, steel reinforcement concrete cover, the use of steel fiber, and testing for verification. INTRODUCTION Durability design is increasingly being recognized as an essential component of good design practice. Infrastructure owners recognize that to serve the public interest, constructed facilities must be lasting and durable. The public understands that structures with limited service life result in increased costs and add to their daily inconvenience with frequent repair and reconstruction. Engineers are increasingly asking not only is the structure strong enough but will it last for generations. Durability design requirements are no longer just adherence to some accepted practices, but are based on analytical approaches, with results that can challenge our beliefs in what construction materials and details result in a durable structure. This paper describes current industry requirements and practices for durability design of underground structures, and offers some suggestions regarding future trends and developments. SERVICE LIFE DEFINITION The service life of a structure is the sum of the time to onset of deterioration, called initiation period (ti), and the subsequent time period of deterioration ending when the structure is no longer functional, called propagation period (tp). Figure 1 shows a conceptual service life diagram. These time periods can be substantially affected by the level of maintenance performed during the life of the structure."

Jan 1, 2016

By George M. Potter

During the late 1960s the mining industry became interested in USBM's efforts to develop the gold-silver heap leaching process. In the last 10 years, successful commercial heap leaching applications increased. The process provides a relatively low-capital means of processing treatable ores with reasonable operating costs. Present gold and silver prices compared to capital and operating costs favor the continued growth of the heap leaching method. The heap leaching process is defined as the percolation leaching of relatively coarse gold-silver ore piled on an impervious surface. To date, dilute alkaline cyanide solution is the lixiviant of choice. Other leaching reagents such as thiourea and hypo have been suggested, although they are not currently used in heap leaching practice. Ores may he run-of-mine in size or crushed as fine as about 10 mm. Gold and silver-bearing so¬lutions draining from the heaps may be processed in activated carbon columns to recover the metals, followed by stripping and metal recovery, or treated by the Merrill-Crowe zinc dust precipitation method. All solutions are generally recycled to the leaching step, and the heap leaching system is relatively easy to control from an environmental viewpoint. One advantage of the heap leaching process is its flexibility. Plants may be very simple, comprising leaching of uncrushed ore on a locally-obtained clay-lined pad and shipment of gold and silver recovered in the form of loaded carbon or zinc precipitates; such a plant would have a relatively low capital investment. More elaborate plants for larger ore bodies may be planned to include crushing, cyclic pad use, and done gold-silver recovery. General planning is similar in each case. This article outlines some key factors in designing heap leaching operations and discusses how these factors are applied to develop a working operation. Since individual design requirements and local costs vary so much, only a few general comments on costs are included.

Jan 3, 1981

By R. W. Henn

Introduction Shotcrete, by the American Concrete Institute definition, is mortar or concrete pneumatically projected at high velocity onto a surface. The term gunite is still common in literature. It is a trade name established by Cement Gun Co. of Allentown, PA, around 1911 for a dry mix of fine aggregate material, hydrated at the nozzle, and pneumatically projected at high velocity onto a surface. This article will discuss shotcrete applications, ingredients, mix proportioning, batching and mixing, admixtures, testing, and steel fiber vs. conventional shotcrete. Applications Shotcrete is used primarily by the mining and underground construction industries to temporarily stabilize an excavated rock surface until a permanent cover can be installed. It may also be used as the permanent covering material. Other uses include refractory material, architectural finishes, slope stability, wearing surfaces, repairing existing concrete structures, fireproofing, and corrosion protection of steel. Wet Versus Dry Process In the wet process, all ingredients, including water but not accelerator, are mixed the same way as normal concrete before its placement by pneumatic projection. The accelerator is added in a liquid state through the nozzle at the point of placement. In the dry process, all ingredients, including acceleration in dry form but not water, are mixed just before placement by pneumatic projection. Water is added through the nozzle at the point of placement. Liquid accelerator may be added at the nozzle in the dry process. Ingredients Shotcrete consists basically of the same ingredients as concrete with some limitations. Type I, II, and III cements are used. However, Type II seems to be used most in underground applications. This can be attributed to ground water at most sites having slight to moderate concentrations of sulfates. Air-entraining cement or air-entraining admixtures are generally not used in dry mix shotcrete. It is generally agreed that it is impossible to entrain air due to the absence of the usual concrete mixing action, and the high velocity of impingement of the material on the application surface. Air-entraining cement or air-entraining admixtures are used in wet mix shotcrete. Their use, however, is not widespread due to the placement method and the fact that high velocity air drives off most of the entrained air. Test results are not conclusive in showing any durability increase of shotcrete to freezing and thawing by using entrained air. In spite of current practice, the trend is toward additional research, with more agencies and owners requiring the use of entrained air. The philosophy behind this is that some entrained air is better than no entrained air to increase durability to freezing and thawing. The aggregates used in shotcrete are the same as those used in concrete. However, the largest coarse aggregate presently used is 19 mm (0.75 in.). A typical gradation requirement is shown in Table 1. The water quality requirement for shotcrete is the same as that for concrete. Accelerators are by far the most important admixture in shotcrete.

Jan 6, 1984

By Jim Salley, Mohammad Saleem, Indra Banerjee, Kevin Sapp

"On underground construction projects, effective Quality Management is essential for ensuring facility durability, life cycle performance and low maintainability. Furthermore, follow on contracts also rely on an effective quality management system for interface congruency. An effective Quality Management System (QMS) is also essential in mitigating risks and meeting schedule and budget performance objectives. For the past 15 years Central Puget Sound Regional Transit Authority’s Link Light Rail extension has successfully completed over 10 miles of twin bore tunneling and associated underground features including cross passages, deep sump structures and shafts. After the completion of each segment, lessons learned have successfully been implemented to improve the quality of delivered projects. This paper presents the Sound Transit QMS with regard to a number of project elements of tunnel construction projects, with specific focus on quality performance of slurry wall construction, TBM tunnel excavation assessment, segment production and segmental lining installation, and other associated construction features. A collaborated total QMS will be presented in this paper that will serve as a guide for successful implementation of Quality Assurance and Quality Control processes. INTRODUCTION Implementation of a robust Quality Management System reduces defects, errors and omissions, identifies and addresses nonconformance in a timely manner and increases stakeholder confidence in the project. In fact and effective QMS helps ensure that optimal project outcomes are realized both in terms of project delivery and life cycle performance. The two key components of QMS are quality control and quality assurance. Quality Control (QC) is the procedure implemented to achieve a certain level of quality and ensure that products, processes and services meet specific requirements. Quality Assurance (QA) activities are carried out to evaluate the effectiveness of the quality control measures and ensure that the QC process is working. A team obligation that recognizes that quality is built into every aspect of a project is the basic concept of a successful QMS."

Jan 1, 2016

By Tyler A. Dawson, Ryan P. Butler, Timothy Gualandri, Jason R. Edberg

"In the early 1920’s, the City of Tulsa, Oklahoma constructed an approximately 8,238-foot long tunnel, the Tiawah Tunnel, through bedrock. Voids behind the concrete tunnel liner were detected via probe drilling in early 2000 as part of an interior visual condition assessment. In 2012 and 2015, conditions along the entire tunnel were efficiently assessed through geophysical investigation using ground penetrating radar (GPR) along the inner tunnel crown and at various select locations within the tunnel. Fifty-seven (57) potential voids, extending up to 19 inches in depth and 12 feet in width, were detected with 1,000 MHz GPR and confirmed through probe drilling with approximately 80% accuracy. GPR proved to be an efficient and reliable technology for void detection behind concrete tunnel lining. This paper highlights the geophysical investigation and how geophysical efforts were combined with other investigation efforts to definitively determine the presence of voids outside of the tunnel lining.INTRODUCTION The city of Tulsa, Oklahoma has a population of about 400,000 people. The original source of water for the city was the Arkansas River. The first pumping operation provided untreated water to homes and businesses in 1904. The residents of Tulsa found this water to be unacceptable due to the high levels of salt and gypsum present. As the city grew, land and storage/treatment facilities were acquired in order to obtain and distribute a more suitable raw water. The raw water needs for the city are currently satisfied by transport and treatment of about 100 million gallons per day (MGD) of water from surface water sources. Water is transported many miles from Spavinaw/Eucha and Oologah lakes to Yahola Lake and the Lynn Lane Reservoir (totaling over 3-billion gallon capacity). From here, the raw water is treated and transported to the various customers (City of Tulsa 2015). The Tulsa Metropolitan Utility Authority (TMUA) is responsible for the operation and maintenance of the raw water transport system."

Jan 1, 2016

By Eivind Grøv

"INTRODUCTION Tunneling and underground excavation is related to handling of uncertainties, risks associated with geological conditions are significant and ‘unexpected geological conditions’ often claimed. This fact was brought to the table long ago, and ITA (the International Tunnelling and Underground Space Association) published its 25 Recommendations on Contractual Sharing of Risks in 1988 (Ref. 1). This public-cation constitutes an important asset to the tunneling industry in terms of being a guideline for those working with contractual issues, even today almost 30 years after being published. A more recent document is the ITIG code of practice for risk management of tunnel works from 2015 (Ref. 9). Various countries or geographical regions have their own view and tradition on risk sharing and tunnel contracts. In Scandinavia unit rates contracts are most commonly used with bid-build model, it shares risk between owner and contractor, owner retains the risk for geological conditions while contractor carries risk for performance efficiency. Rock strengthening is determined assessing rock mass quality encountered at tunnel face. Grouting is applied to stem water. Actual quantities may differ from the contract’s BoQ but a flexible contract with remuneration is installed to enable adjustment of actual quantities. Variations of quantities involve a clause to adjust construction time. Unit price contracts deals with expected and foreseen still ‘unexpected geological conditions’, if the ‘unexpected’ element results in variations in quantities. Work activities have quantities and ‘standard capacities’ for regulation of construction time. Variations in quantities are expected in tunnelling and hardly deserve the term ‘unexpected’. If truly unforeseen geological features necessitate work not included in the BoQ, then the contract must be supplemented and can be said to be inappropriate. Fixed price contracts may not provide the intended predictable cost and is as such also inappropriate in the view of a risk sharing principle, once the geological baseline proves to be incorrect. ‘Adjustable fixed price’ contracts, combining unit rate and fixed price, may prove suitable."

Jan 1, 2016

By Kevin Fitzpatrick, Carmen Scalise, Patrick Jensen

"The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) owns and operates the Tunnel and Reservoir Plan (TARP) system which was adopted in 1972. TARP is a network of 110 miles of deep tunnels and ultimately 3 large reservoirs to combat waterway pollution and flooding within a 350 square mile area served by combined sewers. The original TARP concept included additional tunnels to convey CSOs from the largest storms to the reservoirs. With the initial TARP tunnels complete and the reservoirs nearing completion, MWRDGC commissioned hydraulic and hydrologic modeling studies to analyze the benefits of additional conveyance tunnels. These updated studies optimized the configuration of additional tunnels considering integration with potential future local sewer system upgrades. The alternatives considered several routes of 25, 30, and 35 foot diameter tunnels, ranging from 10 to 18 miles. Alternatives were analyzed based on projected reductions to basement flooding compared to the relative costs. TUNNEL AND RESERVOIR PLAN After World War II the Chicagoland area underwent rapid growth and development. With the Metropolitan Water Reclamation District of Greater Chicago's (MWRDGC) service area becoming increasingly impervious, the flat Chicago landscape was increasingly at risk of significant flooding. In the mid and late 1950's, Chicago experienced multiple extreme storm events that had significant impacts on the city and generated the momentum necessary to initiate what would ultimately become one of the world's largest civil works undertakings. In 1957 a Flood Control Coordinating Committee was formed, consisting of representatives of the MWRDGC, Illinois Department of Public Works, Cook County, and the city of Chicago, to review various plans and develop recommendations for a course of action. With more than 50 alternative concepts being identified, the Tunnel and Reservoir Plan (TARP), which itself is a composite of various alternatives, was adopted the by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) in 1972. The need to adopt a long term plan was further influenced by the Clean Water Act, which was enacted only 8 days prior."

Jan 1, 2016

By Rory P. A. Ball, Mark Briggs, Martin Dix

"Tunnel professionals should inform project stakeholders on the reality that tunnel projects are not 100 percent devoid of the need for excavations or public inconveniences during both design and construction phases. Competing stakeholder objectives to limit these disruptions must be weighed against the need to mitigate risks and to produce a constructible, operable and maintainable end product. Perhaps the approach we should take with stakeholders, also known as Authorities Having Jurisdiction (AHJs), is sharing memorable case studies that bring to life the potential risks so often buried within lengthy risk registers. This paper provides a sobering case study describing what can occur if the presence and/or location of utilities and other obstructions are not fully understood due to restrictions placed on exploration or mining operations. In this instance, the Microtunnel Tunnel Boring Machine (MTBM) encountered a buried concrete structure, followed by rows of abandoned wood piles, before finally colliding with an active high-pressure gas main under a bustling coastal highway. Multiple stakeholders imposed tight logistical and other work restrictions, compounding the difficulties experienced during the drive. However, the difficulties were effectively managed through the project team’s proactive collaboration and communication with everyone involved. INTRODUCTION Some of the most important decisions that influence the ultimate success or failure of a project may not be made by design engineers. Instead, these decisions are often made by project stakeholders and third-party agencies. Tasked with protecting the best interests of their users, these agencies are cautious of potential impacts associated with project construction and subsequent use. Unfortunately, actions required (or restricted) by stakeholders often result in unwanted ripple effects that negatively affect the very users they are trying to protect. For example, a mandate limiting a shaft site to an unreasonable size may be intended to reduce local business impacts, but may actually increase impacts as more supply and truck hauling is required."

Jan 1, 2016

By Peter Moser, Michael Hitch, Michael Tost, Susanne Feiel

"Impact and Benefit Agreements (IBAs) are intended to be a negotiated agreement between an industrial proponent and a community, local or regional citizens’ organization. Although the elements have grown over the past two decades from a simple agreement to exceedingly complex legal frameworks, the intention remains the same: to outline the roles and responsibilities of the two stakeholders and the natural resource development on their lands beyond environmental assessment. These agreements were born out of comprehensive indigenous land claims and have become the cornerstone of community engagement today in most indigenous nations. In the case of mixed communities, those that have beneficiaries of land claims and those who are not, social acceptance remains uneven and reflective of an unequal distribution of decision-making power (political ecology). This Differential Social License can cause conflict and a breakdown of the societal fabric that binds communities of diverse populations, resulting in inequality, fictitious wealth generation and failure of infrastructure. This paper presents a case study of how the development of Differential Social License developed in the Hamlet of Cambridge Bay, Nunavut as a result of an IBA negotiated between Tahera Diamond Corp. and the Kitikmeot Inuit Organisation in 2004 for the Jericho Diamond Mine.Introduction / Background Social license (social license to operate or SLO) has become an essential part of the social governance ‘toolkit’ demanded by mining stakeholders in today’s world. Stakeholders are now insistent that companies operate more closely under the tenets of sustainable development and provide for an increased level of community participation. Social license is not simply a matter of communicating with a community, to earn its consent for or acceptance of a project. It requires that we engage with the individuals and organisations who ally themselves with communities, or who sometimes side with dissident factions of a community. SLO is a process associated with and informed by political ecology or the recognition that unequal decision-making power exists amongst stakeholders."

Jan 1, 2017

"INTRODUCTION Foam, unless intentionally created, in any industrial process presents operational problems, or at a minimum, is a nuisance. Some foam problems are unique to a given industry and others are common across many industries. A few problems foam presents to any particular industry are: (a) Poor Housekeeping, (b) Environmental impact, (c) Safety Hazards, (d) Slower Production Rates and, (e) Reduced quality of the end product. Defoamers address these issues. Sadly, the assumption in most industries is all defoamers are alike. In reality, a lot of chemistry is involved in the manufacture of even the simplest defoamer sold today and rarely are any two defoamers “just alike”. Today’s defoamers can include polymer chemistry, fatty esters, alkoxylated alcohols, silicone chemistry, silicone surfactants, ethoxylated and propoxylated block polymers, and a tremendous amount of emulsion chemistry just to name a few. This paper will discuss the various types of defoamers, defoaming mechanisms, the advantages and disadvantages of defoamer selections, and how to choose the proper defoamer for your application. Before a discussion of defoamer can be brought about, foam generation and composition must be discussed. WHAT IS FOAM? Foam is a colloidal suspension of a gas dispersed in a liquid. Most often foam consists of air dispersed in water. If a stream of air is introduced into a liquid, the bubbles produced assume a spherical shape. As the density of the bubble is less than the liquid the bubble rises. When the individual bubbles reach and pass through a surfactant free liquid they collapse. Air from the bubble dissipates and the liquid previously surrounding the bubble flows back.It should be noted a pure liquid will not foam. In the case of air dispersed in water a surfactant is necessary to make the water support a stable foam. A surfactant is a term used to describe a surface active agent; a compound with a hydrophilic end and a hydrophobic end on the same molecule."

Jan 1, 2016