Search Documents

The development of technologies to improve mining and mineral processing is an ongoing process. These new technologies are the result of the industry’s drive to lower costs and improve productivity. Many technical conferences allow mining industry professionals to learn about these new technologies and possibly implement them in their own operations. In early November 2005, The 14th symposium on Mine Planning and Equipment Selection (MPES) was held in Banff, Alberta. It was jointly held with the Fifth International Conference on Computer Applications in the Minerals Industries (CAMI).

Jan 1, 2006

By R. J. F. Goodfellow

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

By R. Snoby

Since its introduction in 2002, the modern air jig has processed a wide array of coals throughout the world. This paper explores the reasons and justifications for the installations and provides case history performance data. Specifically highlighted are air jig plants processing metallurgical coal in Colombia, bituminous coal in the United States and India and lignite in the United States and Spain. Each installation has unique reasons to justify an air jig facility. It is important to note that not all of the justifications were based on the ?most cost effective yield?, normally a mantra for coal preparation plant designers and owners. Dry jigging of coal has long been a proven technique for upgrading coal, the modern air jig, with its improved efficiency and operating systems simply extended the range of applications. In some cases, it even allows market quality coal to be produced when no other option is possible.

Jan 1, 2009

By Martin Stone

Industrialized countries, particularly the United States and the United Kingdom, remain at the forefront of international efforts to control the potential disruption from computer malfunctions caused by the date change from1999 to 2000 — widely known as the millennium bug or Y2K. Disruption is least likely in the developed world, including the United States, Canada, western Europe, Japan and Australasia. However, the picture is potentially different in developing countries where many mining companies operate. The less developed the country, the greater the chance of some form of Y2K-linked disruption.

Jan 1, 1999

By Michael J. Robison, Wojciech F. Klecan, Robert L. Horner

Since 1928, nearly 64 km (40 mi) of tunnel have been excavated within the relatively soft Cooper Group, more commonly known as the “Cooper Marl,” for water supply and transporting wastewater in the Charleston area. The majority of these tunnels are unlined and still in operation, while others collapsed shortly after excavating. Tunnel behavior and support requirements vary considerably in this material due to differences in geotechnical properties. The 4.8 km (3 mi) long, 2.4 m (8 ft) diameter Bushy Park Water Tunnel, completed in 1997 for Charleston’s Commissioners of Public Works(CPW), required no ground support. By comparison, the 1.6 km (1 mi) long, 2.4 m (8 ft)diameter Harbor Wastewater Replacement Tunnel now under construction needs continuous support close to the advancing face, despite being located in the same geological formation. Case histories and general guidelines for designing tunnels in the Cooper Marl are presented.

Jan 1, 2001

Lime production is the largest single chemical use for limestone and dolomite. The term “lime” in this review refers to high-calcium and dolomitic quicklime, their hydroxide forms and dead-burned dolomite. This review is restricted to a discussion of the U.S. lime industry. Production and consumption In 2004, according to preliminary data, U.S. lime production was about 20.1 Mt (22.1 million st), an increase of 900 kt (990,000 st) compared with 2003. Production in2004 was valued at about $1.4 billion. Commercial sales of lime totaled 18.6 Mt (20.5 million st) and captive production was 1.5 Mt (1.65 million st). Total U.S. consumption was about 20.2 Mt (22.2 million st). The majority of U.S. lime trade was with Canada.

Jan 1, 2005

By Michelle L. Ramos

INTRODUCTION The Ballard Siphon was built in 1935 and consists of two 91.4 cm (36-inch) diameter wood-stave pipes. These pipes convey sewer flowsunder the Ship Canal from northwest Seattle and the Ballard Regulator to the North Interceptor and the West Point Treatment plant. The siphons were constructed using open cut construction, are now buried in the sediment on the floor of the canal, and have severely limited ability to be dewatered, inspected, or cleaned. The existing siphon is 394.7 m (1,295 feet) long from the junction structure on the southern shoreline to the regulator structure on the north. The location of the Ballard Siphon is shown in Figures 1 and 2. The area around the Ballard Siphon has become more populated and developed since the siphon was built. Additionally, the Ballard Siphon is subject to high flows that are greater than the capacity of the pipelines. This has resulted in predict-able Combined Sewer Overflows(CSO?s) whenever a large, long duration rain event occurs. The aged pipeline of uncertain viability has become a critical piece of the sewer system infrastructure. Because of the age of the pipelines and their importance, a sonar survey was completed on both barrels of the Ballard Siphon in December of 2005. The sonar images appeared to indicate crown intrusion of the wood-stave pipes, which suggested that the pipes were in imminent danger of collapse. As a result, an Emergency Declaration was executed by King County and the Ballard Siphon Replacement Project was initiated. Staheli Trenchless Consultants was retained to perform feasibility studies to deter-mine the viability of using microtunneling and horizontal directional drilling (HDD) for replacement of the Ballard Siphon. For the evaluations, the preferred site location was determined to be at or near the site of the existing Ballard Siphon in order to minimize the ancillary sewer work which would accompany moving to a new site. To meet flow demands and hydraulic requirements, the replacement siphon needed a mini-mum equivalent diameter of 182.9 cm (72 inches). This could be accomplished with a number of different siphon diameters and configurations including, but not limited to, three 106.7 cm (42-inch) diameter pipelines, two 152.4 cm (60-inch) pipelines, or two 91.44 cm (36-inch) pipelines and a 121.9 cm (48-inch) pipeline.

By G. A. Gamble

Fans used to ventilate subway, passenger rail and vehicular tunnels are similar to the fans used to ventilate underground mines. However, tunnel ventilation fan systems are typically designed to meet NFPA 130 or 502 standards, while mine ventilation fan systems must comply with the appropriate federal mine safety regulations. As a result, fan operation requirements and performance criteria, as well as typical fan and duct configurations differ significantly for tunnel and mine ventilation applications. Variations in environmental conditions in tunnels as compared to mines also result in differences in fan performance and material specifications. The need to enclose tunnel fans within building structures creates space restrictions impacting fan size selection that are not commonly encountered in mine fan installations, resulting in different approaches to selecting fans for the two types of tunnels. This paper discusses the various similarities and differences in design considerations for tunnel and mine ventilation fans.

Jan 1, 2009

By Raja V. Ramani

As the new millennium approaches, it is appropriate to assess the progress that has been made in mine health and safety, a matter of concern to management, labor and government. One can hardly look at the major events of the last century — from the birth of the US Bureau of Mines through the enactment of the modern health and safety laws — without realizing that the march has been relentless toward eradication of health and safety threats in mining. The progress is spectacular in mine safety and significant in mine health. In looking at the future, it is safe to assume that societal demands will increase for improved health and safety conditions in the workplace. So will the demands for greater technological leaps. The standards will for measuring success and the expectations of progress in creating a safer and healthier mine environment will grow. The possibilities are enormous of meeting these exacting requirements in the 21st century.

Jan 1, 1999

By C. James, J. Siefke, D. Shumway

The Mojave Desert is a particularly fragile ecosystem that faces several significant impacts. These include rapid housing development, overdrafted water supplies, and loss of wildlife habitat as a result of mining, industrial activity and urban sprawl. Over the past three years, a diverse group of educators, natural resource managers and business leaders has been assembled under the auspices of a local college to provide unique natural resource education opportunities for the region. By leveraging the collective experience of these present generation natural resource professionals, the Mojave Sustainability Project hopes to provide the next generation of professionals with that knowledge and those technical skills upon which tomorrow’s community can rely. This paper is a case study of how partnerships between academia, government, industry and the community can serve to address the regional social, environmental, and economic needs of today, while investing in the development of those professionals who will balance these needs tomorrow.

Jan 1, 2005

By Paul C. Schmall, Thomas Tuozzolo, Arthur B. Corwin

The Lenox Avenue Reconstruction Project involved the excavation and replacement of 750 m (2,500 ft) of deteriorated subway invert concrete, 5 to 7 m (15 to20 ft) below water table in very permeable ground. The Replacement work was done over an 8 month period, while maintaining track service through this subway section. The project was dewatered with a single 125 l/s (2,000 gpm) wellpoint system,750 m (2,500 ft) in length, which was installed from inside the active tunnel structure and configured to coexist in the subway tunnel with operating trains as well as the construction activities. A thin diaphragm jet grout wall was utilized on one end of the site to cut off the flow of water across a difficult geological interface that was situated immediately below the tunnel invert. The thin diaphragm jet grout wall permitted the large 116th Street Station area to be dewatered completely with well points from outside of the excavation.

Jan 1, 2001

By D. M. Loring

Radon progeny have been a health and safety concern for miners since the mining of radioactive minerals began. Through the ?nuclear age?, it has become better understood and the regulations have become more robust. Ventilation and control practices have improved, thus reducing miners? exposures. This paper provides an overview of radon in mining, the progress of the regulations, and discusses some of the uranium miner studies that contributed to the knowledge of the pathology of radon.

Jan 1, 2009

By B. A. Osei

Research to evaluate possible metrics for predicting dredgeability of compact aggregates, by hydraulically actuated clamshell dredges, shows work done by the pistons as a viable metric. Analysis of field data shows that there is a low, positive, correlation between cycle time (CT) and work done. If this correlation exists, then CT has to be considered an independent variable affecting work done during dredgeability assessment. Further research is required to elucidate the relationship between CT and work done during dredging. The objective of this paper is to test the hypothesis that work done during dredging increases with increasing CT. Kinematics and dynamics of the hydraulic clamshell were modeled and implemented in Simulink® in MATLAB. The model was validated using field data. The model was then used to test the research hypothesis. The results show that work done increases with increasing CT. This work confirms that work done during dredging increases with increasing CT. This result indicates that though an operator can increase the CT to deal with difficult digging, inputting unduly high CTs results in higher energy consumption during dredging.

Jan 1, 2011

By John E. Rourke, O&apos

This paper describes some of the results of a project for the design and demonstration of subsidence monitoring systems for underground coal mines. The project was designed to test monitoring systems described in an earlier feasibility report (O'Rourke and others, 1979). General objectives of the project were to develop reliable cost- effective monitoring systems for use above caving- type mining operations, over supported mines, and in urban undermined areas. Topics selected for discussion in this paper include a description of the instrumentation systems, the site conditions, problems of installation, resulting recommendations and an over- view of subsidence performance data obtained. There were some particularly difficult problems of installation to overcome at this site. Some of these could be experienced at any surface or under- ground project, others are probably more directly related to Western coal fields. Almost any subsidence monitoring program may face the following difficulties:

Jan 1, 1982

By D. G. Klaren

Self-cleaning fluidized bed heat exchangers are conquering the world for reason that they are able to solve any severe fouling problem in indirect heat transfer due to the circulation of cleaning particles through the tubes of vertical shell and tube exchangers. In most cases, these particles consist of chopped metal wire. Moreover, self-cleaning fluidized bed heat exchangers perform with excellent heat transfer at very low liquid velocities, which makes completely new designs of shell and tube configurations possible. Further, self-cleaning fluidized bed heat exchangers show a strong shear thinning effect in non-Newtonian liquids. All the above characteristics make the self-cleaning fluidized bed heat exchanger an ideal tool for the indirect heating of laterite nickel slurry in High-Pressure-Acid-Leach (HPAL) plants. Preliminary tests and evaluations of these heat exchangers have shown that the performance and price of these heat exchangers used for the production of nickel and cobalt from a laterite slurry, cannot be matched by existing conventional heat exchange systems. This article explains the principle, design, lay-out and enormous advantages of the self-cleaning fluidized bed heat exchange technology in a plant suitable for an annual production of approx. 45,000 ton nickel and 4,500 ton cobalt from laterite slurry through high pressure'acid leaching.

Jan 1, 2002

By W. A. Wilkinson

In creating a surface mine design, a complicated series of events may be required to meet both mining and environmental objectives. Envisioning the mine at every step of the operation can greatly assist the engineer to identify design and operational problems that might otherwise go undetected until the field operations reach the problem. Providing operations a visual progression of the mine ensures that critical designs generated by the engineer are understood and effectively communicated to operations. Providing the plan as electronic data to the surveyors and/or on-board GPS systems can ensure successful implementation of the design. This paper discusses using computer technology to generate a virtual mine plan and strategies to consider when communicating a virtual mine plan through electronic and paper formats.

Jan 1, 2002

The Pogo Mine, near Delta Junction, Alaska is a new 2500 STPD gold operation. The control system of the mine and milling operations are a hybrid of DCS (Distributed Control System) control and PLC (Programming Logic Controller) control. A DeltaV DCS system serves as the main control and operation platform while the PLCs operate a multitude of vendor specific packages. The communication backbone of the DCS system is a hybrid of star and ring fiber optic topology, which provides reliability and flexibility. The communication between the DCS and PLCs is typically facilitated by serial communication. This communication insures the integrity of the whole control system.

Jan 1, 2008

By Werner Burger

The Hallandsås project with a long history, first started in 1991, is well known in the tunneling community. In the past it has been stopped twice for technical and environmental reasons. The third attempt started in 2004 using a dual mode rock TBM. The heterogeneous highly fractured and abrasive rock mass as well as large areas of water bearing zones present most difficult subsurface conditions. The tunneling concept is based on the use of watertight segmental lining and a TBM able to operate in open mode, possibilities for extensive pre excavation grouting and high pressure closed mode operation up to 13 bar to cover exceptional conditions.

By E. V. Manlapig

This review paper describes recent advances that have been made at the Julius Kruttschnitt Mineral Research Centre (JKMRC) in Brisbane in developing a framework for simulating the flotation process. The work has been carried out collaboratively with the Mineral Processing Research Unit of the University of Cape Town in South Africa (UCT), as part of the Australian Minerals Industries Research Association (AMIRA) P9 Project. The framework consists of four components, namely – the mathematical model of the flotation process, suitable measurement tools for characterising the flotation cell, a computer program for modelling and simulating the process and the plantas for testing and validating the flotation models. A brief description of the model is first presented, then a number of applications of the model are described. The paper shows how the model can be used to optimise the performance of flotation cells, and then two case studies on the modelling methodologies are described. Finally the current and future plans of the project are outlined.

Jan 1, 2001

By Refik Elibay, Lawrence A. Williamson, George D. Barnes

Under an extremely aggressive schedule, final design of 13.5 km (8.4 miles) miles of 8.2 m (27 ft) diameter deep rock tunnel, 322 ML/day (85 million gallons / day)submersible pumping station and associated facilities were accomplished ahead of a federal court mandated consent decree schedule. Challenges overcome by the project team in enabling timely completion of the construction documents will be presented. Discussion includes evolution of final design, consideration of future O&M requirements, and risks identified for construction and operations, together with measures to manage and proactively prepare for such risks.

Jan 1, 2005