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By Jean-Luc Cornet

As modern conveyors are increasing in size and complexity, their control requirements are becoming more and more critical. In addition to the safety and equipment protection requirements, control systems are now called to implement intelligent drive controls derived from dynamic analysis modelling, as well as to provide fast and accurate diagnostics while keeping operator controls simple. These requirements led to the development of a new and innovative approach to control system development. This paper describes the control philosophy used by Conveyor Dynamics, Inc. (CDI) and some of the key features of our approach to the architecture of control systems.

Jan 1, 1993

By K. Hanumantha Rao, K. S. E. Forssberg, H. R. Manouchehri

The responses of calcite, feldspar and quartz minerals in a laboratory free-fall electrostatic separator after tribocharging with stainless steel, PVC and copper plates were investigated. The effects of H3BO3 and BaC12 chemical pretreatment on the electrical properties of the above minerals were examined. The changes in the electrical properties are discussed along with the determined charge, dielectric constant and electrical conductivity of the mineral samples. The electrical properties of the minerals and their responses to the electrical field during separation after tribocharging and chemical pretreatment are explored relative to the electrical behavior of the minerals.

Jan 1, 2000

By Ignacio González, Marcos Monroy, Valerie Bertrand, Roel Cruz

Results of an electrochemical study using carbon paste electrodes of pyrite and pyrrhotite samples suggest that the mineralogical impurities associated with these minerals are the determinant factor on their reactivity under alteration systems. These results were supported by mineralogical and leachate chemistry data from leach cell tests run on these samples. Pyrite reactivity decreases in the presence of associated impurities due to a galvanic effect whereas pyrrhotite reactivity appears to be controlled by the formation of a passivating layer, which overcome impurities effect. Electrochemical responses of sulfide-bearing samples provided valuable information on the prediction of ARD generation.

Jan 1, 2000

By Angus Campbell, Michael J. Gobla

Numerous techniques for treating, controlling, and preventing acid rock drainage have been applied at the Summitville Mine Superfund Site. Challenging aspects of the remote mine site include the wide-spread occurrence of acid-generating soils and rocks, extensive surface and underground mine workings, and a cold and wet climate. Water treatment was an immediate necessity when the Government took control of the abandoned site in December of 1992. Subsequent reclamation activities have emphasized prevention and control of ARD to minimize future water treatment requirements. A combination of conventional, innovative, and experimental methods are being applied to successfully mitigate ARD at Summitville.

Jan 1, 2000

By R. H. King, R. E. Cameron

Mine managers need better information to locate new opportunities and then to assess the effect of their decisions. We are developing the Intelligent Decision Support System (IDSS) and its two major modules, the Pattern Recognition System (PRS) and the Knowledge Representation Subsystem (KRS) to automatically provide the information from monitoring system sensors. This paper focuses on the KRS Algorithms that extract key information from lists of time-study type event sequences. Because a static system cannot operate effectively in a dynamic mining environment, we are prototyping an index- based technique that allows the system to adapt itself to this dynamic environment.

Jan 1, 1991

By Kurt Zeidler, Vojtech Gall

London Underground Limited are currently constructing an extension of the Jubilee Line. The approximately 16-km long Jubilee Line Extension Project connects the existing Green Park Underground Station with the Canary Wharf area and Greenwich. Being a part of the project, the London Bridge Station (Contract 104) was built using a combination of the New Austrian Tunneling Method (NATM) with Compensation Grouting. NATM was successfully applied in softground and urban areas under restrictive requirements regarding settlement limitation. Information on the flexibility of the method and the influence of Compensation Grouting on ground and tunnels are given.

Jan 1, 1997

By Gus Van Weert, Roy van Lier

It has been demonstrated for two totally different silver bearing and cyanide refactory concentrates that the formation of silver jarosite can be prevented through the addition of iodide to the autoclave feed. A molar ratio of r/ Ag+ of no more than 1 was sufficient to raise silver extractions in a subsequent cyanide leach from 4% after autoclaving without iodide addition to 98% for the sulpho-salt concentrate and from 15% to 97% for the pyritic acanthite concentrate. Flowsheet proposals will be discussed to prevent loss of the iodide additive. The use of chloride instead of iodide will also be reviewed.

Jan 1, 2000

The American Mining Congress International Coal Show, this year’s largest gathering of coal industry leaders, convened May 5-8 in Chicago. Against a 73 000-m2 backdrop of the coal industry’s most productive equipment,* some 23 000 people heard government and industry executives give guardedly optimistic reports of coal’s near future gains. Although a rocky road lies ahead, operators and suppliers still continue their search to improve efficiency. Among the ideas discussed at the show were better underground communications systems, continuous on-line coal analysis, and recovery of hard-to-float coal.

Jan 7, 1980

By F. F. Aplan, C. E. Raleigh

Three run-of-mine bituminous coals, ranging in rank from low volatile to high volatile A, were floated at nominal -28 mesh (590 µm), -100 mesh (150 µm), and -400 mesh (37µm) feed particle sizes with selected pyrite depressants and a dispersant. For the three coals tested, pyrite and ash -forming minerals were usually rejected best at -100 mesh feed particle size. Depressant additions tended to improve flotation selectivity between pyrite and coal. When joint dispersant-depressant systems were used at -100 mesh (150 µm) feed particle sizes, the total sulfur content of the clean coal decreased further. For a comparable coal yield, less fuel oil collector was required for the flotation of -100 mesh coal than was required for the flotation of either -28 or -400 mesh feed.

Jan 1, 1992

By M. R. Fletcher

Slags generated by the ferrous metals industry can he used to produce high-value ceramic materials. The properties of these ceramics can be controlled by judicious choices of composition, additives, and processing parameters. Standard methods of materials handling, such as comminution and mixing, are as applicable to slag as to any other mineralogic raw material. In this study, foundry slag was ground, homogenized, melted, and, formed to produce a glass, and then heat treated to crystallize it into a high-strength glass-ceramic. The product shows promise as a low-cost, wear-resistant tile material that (-an he custom cast. This and similar materials made from slags and natural rocks are candidates for use as construction materials, acid-resistant piping, shock-resistant sheathing, rot-proof pilings, and, when foamed, even as pontoons.

Jan 1, 1990

By G. D. Ritson

Gold surveys were sent to 21 gold operations around the world. Eleven different surveys were sent, each targeting a dif­ferent unit operation used commonly in gold processing. On a monthly basis the individual reports were returned to the opera­tions. Empirical data collected during the surveys has con­tributed to more effective engineering design. Graphical rela­tionships established have been used by the operations to "benchmark" performance against the industry and identify areas of possible improvement. This paper presents some of the findings related to the fol­lowing four surveys that investigated parameters specifically relating to carbon processing. Rescan Gold Survey GO 1 - Carbon Management practices Rescan Gold Survey 003 - Carbon Stripping Rescan Gold Survey 006 - Carbon Loading Isotherms Rescan Gold Survey 007 - Screening A final report documenting all the surveys will be compiled

Jan 1, 1998

By Shelley M. Burg, Dennis K. Poulton, Robert B. Gordon

This project includes the excavation and concrete lining of approximately 18 900 m (62 000 ft) of 5.5 m (18 ft) finished diameter subway tunnel for the Los Angeles MTA. The project required that four soft ground headings be excavated from a single shaft located near the mid point of the tunnels. The tunnels were classified "gassy" during the excavation phase. Because of the contract schedule requirements and the limited urban work site available, many logistical problems had to be overcome during the project while excavation was accomplished at a record setting pace. Some unique project features include the muck handling system and an access shaft using a high strength tieback support system. In order to accomplish the work, an extensive effort to plan and construct the main work site was required.

Jan 1, 1995

By J. E. House

Creative ideas and endeavors require imaginative and positive responses, if they are to be reduced to practices. This lecture will define the plurastic roles of various technical disciplines which were important in the development of the LIX reagents. Specific personalities, facts, and events will be used to trace the development from an idea, to the exciting acceptance and practice of the technology. An objective analysis of the entire LIX reagent development, spanning twenty-five years experience of the author, will be given, these will be used as a basis for critical examination of how the various technical disciplines could improve their effectiveness in advancing future technologies.

Jan 1, 1990

By David R. Zuchelli, Elio L. . Checca

Two case studies of methane gas explosions and their effect on the operation of underground coal mines are presented. The studies detail the recovery operations and investigations at each mine site. These include the circumstances prior to the explosions and the effects on the surface and underground ventilation control systems. Various ignition sources such as surface and underground electrical power systems, degasification sites, ventilation shafts, test well casings, and lightning activity were investigated. In each case, a lightning report from the National Lightning Detection Network1 was used in conjunction with the physical evidence and eyewitness accounts to confirm lightning strikes as the ignition source for the explosions.

Jan 1, 1995

By Roy J. Leonard

Two small diameter sewer tunnel projects being hand dug under major highways in the Greater Kansas City area encountered problems which were unforeseen from the geotechnical engineering information supplied with the contract documents. Both tunnels were being excavated by experienced crews using steel liner plates. One required the use of compressed air for completion, while the other required poling boards. Both contractors overran their budgets and filed changed condition claims, and this promoted further geotechnical engineering investigations. Fissured clays beneath a water table were encountered at both sites, but the character of these clays differed; however, both were inadequately described in the original geotechnical engineering reports.

Jan 1, 1987

By Lee W. Abramson, Glenn M. Boyce

A dowel testing program was conducted as part of the Interstate Route H-3 Trans-Koolau exploratory tunnel project on the island of Oahu, Hawaii. The testing evaluated the performance of dowels to be used as initial ground support for two 12- by 15-meter (40- by 50-foot) tunnels within weathered basalt. The program tested four dowel types of three different lengths. Both grouted and friction dowels were tested. The program determined which dowels were more effective in carrying load and noted any special procedures that would be required during construction. This paper presents the test results and discusses how these results were used in the design.

Jan 1, 1991

A roof rating system has been devel¬oped for upper seam damage prediction during mul¬ti-seam mining based on structural and geologic conditions in the upper seam. Two primary consid¬erations -geologic and spatial - form the basis of the classification system. It includes factors commonly found in geomechanics classification systems as well as factors which are peculiar to multi-seam mining, such as those which define the two adjacent seams and the innerburden. This rating system has been applied to numerous case studies to form empirical relationships for quan-titatively predicting potential upper seam damage based on anticipated subsidence and strain values and vertical movements.

Jan 1, 1988

By Rick L. Williamson

International lending institutions have charters requiring projects that are seeking loans to adhere to certain environmental performance standards, including compliance with host-country environmental laws, as well as observance of international environmental policies and guidelines. The most commonly applied international environmental policies and guidelines are those established by The World Bank. Lenders require a review by an independent engineer to determine that the feasibility study plans have been developed in accordance with the applicable environmental commitments. Lender agreements require independent engineer evaluation of environmental performance through the construction phase and initial operations phase of the project, culminating in the issuance of an "Environ- mental Completion Certificate."

Jan 1, 2001

By Anna Arkhireeva, John N. Hay

Considerable interest has been shown recently in organically modified silicates (ormosils) because of the wide range of possible applications for these interesting organic-inorganic hybrids. These applications include the use of the hybrids as modifiers of a range of host polymer proper- ties. The ormosils can be synthesised by the conventional hydrolytic sol-gel process, as well as by the non-hydrolytic sol-gel route. To date, however, there are relatively few reports of the synthesis of sub-micron size ormosil particles of well-defined spherical morphology. Here, we report work to date on synthesis of such nanoparticles and also introduce our own work in the area.

Jan 1, 2003

By Jürgen Brune, Purushotham Tukkaraja

This editorial introduces a special focus issue on mine ventilation innovations. It highlights key areas such as ventilation on demand, automation, thermal management, atmospheric monitoring systems, and prevention of mine fires and explosions. The issue aims to address the critical role of mine ventilation in maintaining the health and safety of miners.

Mar 21, 2022