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By H. K. Lin, J. L. Oleson

The purpose of this study is to develop a mathematical model to describe the oxidation of cyanide with SO2as proposed in the Inco process. This research employed a direct method for measuring the change in cyanide concentration with respect to time as effected by varying concentrations of SO2, copper and pH. Developing this model may be applicable in determining optimum conditions in a process well known and used in the mining industry. It was determined that the reaction is first-order with respect to cyanide, SO2and [Cu+2].The reaction order is 0.15, or zeroth order with respect to [H+] at pH range from 8.0 to 9.5.The activation energy, Ea, is 21.6 kJ/mol. The overall rate equation, as determined through this study is: [ ]

Jan 1, 2004

By Franz Albert Nonnen

Backfill systems have been used for as long as mining activities have existed. Various backfill methods have been developed over the centuries with consideration for geological necessities, the technical means available, security requirements, and available finances. In the past, backfill systems were introduced and upgraded geographically in accordance with local experiences. In modern times, mining engineers participate in international forums for the exchange of knowledge so that backfill techniques and experiences are shared concurrently in mining areas all over the world. Mine backfilling increases the cost of mining so that great attention must be paid to choose a low-cost, reliable, and low maintenance backfill system. Some methods are described in this paper.

Jan 1, 2001

By David G. Adam

Introduction Syncrude Canada Ltd. is the operating company for a consortium of industry and government participants that produce synthetic crude oil from their leases in the Athabasca Oil Sands. Production from the $2.3 billion (1978) integrated mining, extraction, and bitumen upgrading and utility complex started in September 1978. Production is currently about 6.4 Mm3/a (40 million bbl per year) of high quality synthetic crude oil. This is done by upgrading the extracted bitumen from the oil sands mined. Plans are to increase the production to 8 Mm3/a (50 million bbl pier year) by 1989. At that time, the mining operation will be required to deliver 100 Mt/a (110 million stpy) of oil sand (ore) to the extraction plants, and handle quantities of waste ranging from 50 to 75 Mt/a (55 to 83 million stpy). The Syncrude plant is located at Mildred Lake, 40 km (25 miles) north of Fort McMurray and 480 km (300 miles) north of Edmonton, Alberta. Climate, particularly winter, is therefore a major factor affecting the design and operation of all the Syncrude production facilities. Bitumen production, consisting of overburden removal, oil/sand mining, bitumen extraction, and tailings disposal, account for about half the total SCO production costs. Considerable research and development, therefore, continues to be applied to improve both material handling and bitumen recovery methods. Potential applications for feeder breakers were identified in the material handling aspects of both overburden and oil sand mining to reduce cost and to attain planned production increments. Overburden removal Overburden materials on the leases comprise thin Pleistocene sands, gravel and fill, and sands, silts and clays of the thicker Clearwater Formation with the silt to clay components predominating. The latter contains multiple leases of hard siltstone with unconfined compressive strengths up to 148 MPa and thicknesses up 0.1 to 0.9 m (1 to 3ft). Characteristics of the overburden as well as the climatic environment and scale of operation present unique problems for the efficient removal of the material. In a bucketwheel/conveyor system, the weak silty clay formations require relatively flat working slopes for safe operation, while the siltstone lenses and frozen overburden require blasting or selective removal by other equipment. These factors, combined with the normal bucketwheel/conveyor design parameters, lead to high capital investment and relatively inefficient use of that capital. Hydraulic mining alternatives, including dredging, are constrained by severe clay settling problems in the waste disposal

Jan 6, 1986

By E. Topuz, C. Patrick

Longwall face-to-face transfers can cost more than $100 per minute in lost production potential and $100,000 for personnel and supplies. Such high costs make extensive planning and control of the transfer process a critical necessity for the economic feasibility of longwall operations. Operations research techniques are used for the analysis and modeling of longwall face-to-face transfers. Transfer data has been collected from companies who operate, over 35%, of the total US longwall faces. Comprehensive sequence networks of existing longwall transfers were developed; simulation was used to generate models of transfers under Carving conditions; and the economic feasibility of tine-cost tradeoffs in the transfer procedure was investigated.

Jan 1, 1994

By Carl Pinches

Underground or surface mining is only the first stage in the ore mining process. Once the ore is mined, it is transported to the surface for further processing. Generally, this is done to extract the particular metal or other component of the ore that has commercial value in its purified form. In its raw state, there are typically between 4 and 7 g/t (0.12 and 0.2 oz/st) of valuable material from rock mined. Once on the surface, the ore is crushed and milled in order to obtain smaller rock particles and to expose the minerals that contain the desired metal or component. Mixing the milled ore with water, a process known as ?froth flotation,? can be employed. This technique consists of a series of tanks, or ?cells? through which the process liquid flows. To obtain the maximum recovery, the milling and flotation process will often be repeated a second time. An increase between 100 and 1,000 g/t (2.9 and 29 oz/st) of rock following this stage of the process is typical. Efficient recovery is key to maintaining a profitable mining operation. The measurement and control of the froth flotation process is vital.

Jan 1, 2010

By D. Noon

Mine production crews and drill-and-blast crews may be exposed to unexpected movement of ground when working under pit slopes. Without specialist geotechnical advice and appropriate measurement systems, mine crews are faced with conducting risk assessments and relying on subsequent controls that may or may not be adequate to ensure their safety. Mine crews need an ?early warning? monitoring system to give them the confidence that they will have time to walk out of the danger zone if the pit slope begins to move. Slope stability radar technology is used by mine geotechnical engineers to assess overall slope stability over an extended period, typically days or weeks, and to critically monitor slopes that are actively moving and may become unsafe. The complexity of slope stability radar allows for geotechnical engineers to assess movement types and movement rates across multiple work areas of a mine from long ranges, with alarm capability to a central location. However there are many mine work areas where production and drill-and blast crews are not adequately covered or alarmed by slope stability radar systems. What is required is an easy-to-use, short-range, fast-scanning tool that can be operated directly by a work crew and can provide a local alarm with sufficient warning when a wall movement occurs within the work area. The Work Area Monitor (WAM) concept has been developed specifically to be operated by a mine production crew. The system comprises a sensitive, fast-scanning radar coupled with a high-resolution camera, built into a mine-standard light vehicle. The system has been designed specifically for ease of use with the output being a local area alarm to warn workers of slope movement in their vicinity, as opposed to the broader pit monitoring and long-term deformation measurements of the known slope stability radar systems.

Jan 1, 2012

By H. D. Brenk

"The German Federation of International Mining and Mineral Resources (FAB) is a federation of German companies that are active in international mining and mining related business. The FAB presents a platform for the exchange of information about the worldwide mining commodities in the dialogue with German and foreign institutions. The expertise of the member companies in mining and related activities is based on a long term operation and consulting experience in Germany and abroad. This forms the basis for the special international competitiveness "Made in Germany". The FAB is particularly engaged in the following topics and tasks and acts as a focal point for: • international project developments with the German mining industry, • sustainable mining, consulting and equipment services, • geological and environmental technologies, • project financing and • intermediation of contracts, project enquiries, professional symposia and events. The FAB acts as a contact- and coordination site for international business partners, organizations and governmental authorities. Together with the federal government the FAB organizes bilateral working group meetings in the commodity and mining sector. Project enquiries are being distributed from the FAB among their member companies."

Jan 1, 2011

Draglines are one of the largest land-based equipment moving across the earth. They typically ranging in size from2.5 to 6.5 kt (2,750 to 7,100 st). Their size, though, makes them difficult to maintain. Recently, G&S Engineering Services used an Enerpac synchronous hydraulic lifting system to lift a 3.2-t(3,500-st) dragline at the Curragh Mine in Queensland, Australia’s Bowen Basin.

Jan 1, 2004

By G. P. Tomaino

Talc is a layered, hydrous magnesium silicate mineral. It has a soft, soapy feel and typically a smooth texture. Talc is also known for its insulation, heat resistance, chemical stability, oil absorption and strong covering quality. Talc, Mg3Si4O10 (OH)2, has a theoretical chemical composition of MgO at 31.7 percent, SiO2 at 63.5 percent, and H2O at 4.8 percent. However, talc’s chemical and mineralogical composition can vary depending on its geological history/parent rock association. These mineral associations and variable levels are usually chlorite and carbonates (magnesite, calcite and dolomite). Two key elemental substitutions that can occur in the talc crystal structure are iron for magnesium and fluorine for hydroxyl. These compositional differences may limit or enhance the talc’s usage in specific market niches. The United States remains self-sufficient in most grades of talc.

Jan 1, 2005

By Dean Brox

The use of Tunnel Boring Machines (TBMs) for tunnel construction of long tunnels in the Andes of South America has been of mixed success in the past due to a variety of reasons and key lessons can be recognized. A review of past TBM tunnel projects in the Andes has unveiled some interesting findings for different TBM tunnel approaches with both world records of progress as well as nearly in-completed projects with machines being abandoned. Key considerations for the use of TBMs for tunnel construction in the Andes include geological issues; (faults, rock type, rock strength, rock abrasivity, durability, groundwater inflows),depth of cover and the potential for overstressing/rockbursts, site access and terrain, portal locations, intermediate access possibilities, minimum tunnel size, support requirements, contractor and labour experience, and project schedule demands. TBMs offer highly recognized schedule benefits(high progress, no concrete lining) for a project if intermediate access adits are limited as well as hydraulic benefits for water conveyance projects. Minimum specifications for TBMs can be easily developed to suit the unique requirements of any project so as long as all factors are carefully considered. The overall conditions and factors associated with some projects may suggest that it is not appropriate to use TBMs due to a perceived high risk. Finally, access for geotechnical investigations by drilling in the commonly steep terrain of the Andes is typically difficult and often not impossible. Alternative approaches for geotechnical investigations for TBM tunnels including comprehensive mapping, high-resolution airborne electric-magnetics for delineation of possible fault zones, and rock block sampling is presented and discussed.

By V. I. Lakshmanan, Dan A. Mackie

Traditional vat leaching methods have had limited success, primarily due to the high cost of loading and unloading the vats. In general, such batch methods are labor-intensive and costly. Heap leaching has emerged as a viable, low- cost alternative, but low recoveries, normally in the 70% range, offer opportunities for improvement. Also increased regulatory guidlelines for effluent and spent heap leach pads disposal offer potential for alternative methods. The Mackie Vat Leaching Jig (MVLJ) has had its incubation at Ortech International, where bench scale through pilot scale testing continues. Design developments and testwork over the past two years indicate that the time may be right for field trials.

Jan 1, 1990

By M. K. Eryadin, I. Yildirim, R. Asmatulu

Novel dewatering aids were tested on various coal samples from the U.S. and Canada in laboratory and pilot-scale filtration experiments. The reagents substantially improved the dewatering kinetics and reduced the cake moistures. The cake moistures were typically reduced from 20-30% by weight to 8-14% range in vacuum filtration. When the reagents were used in conjunction with a pressure filter, higher degrees of moisture reductions were achieved. In the present work, the novel dewatering aids were tested using different types of pilot-scale vacuum filters. The results were consistent with those obtained in laboratory experiments.

Jan 1, 2003

By J. Parker

Gentlemen; Rainy day in Upper Michigan, a good time to catch up on reading. Am doing that, and have a couple of questions concerning the K and P paper on roof problems and supports. I wonder if the authors can enlighten me. The compressive strength of the coal was reported as 4.4 MPa (633 psi) and compressive stresses measured in the coal seam were reported at around 27.6 and 48.2 MPa (4000 and 7000 psi ). Can such a soft coal actually contain such a high level of stress? Can it be measured as if the material were elastic, or does the coal behave plastically? Can that stress level be confirmed with hydraulic load cells? And if the coal is so soft, and if it is plastic, why is the stress field not hydrostatic? The intact roofrock appears to be unusually strong, with compressive strength reported at around 145 MPa (21,000 psi), and some failures were noted as soon as the rock was exposed. Were tests run to find out how that rock responded to the addition

Jan 1, 1991

By H. Savasci, G. Yarim, J. S. Chung

As part of ongoing deep-ocean mining research, hydraulic transport systems as well as status of deep-ocean mining systems are reviewed in the aspects of manganese nodules and crusts from 8006,000-m depth. The emphasis of the investigation of hydraulic transport is placed on the shape effect of particles on the pressure gradients and flowrates. Series of tests are being conducted to study the lift characteristics of a 2-phasevertically upward hydraulic transport of 2 types of small solid particles in a PVC pipe of 1-in (2.54 cm) diameter: irregular-shaped silica sands and equivalent spherical glass beads. Pressure drops and mass as well asvolumetric flow rates were measured by electromagnetic(EM) flowmeter and mass flowmeter. The particle sizes used are 8-10 mesh. The results in turbulent flow range of 101045Re show that pressure gradients or friction factors are smaller for the spherical beads than the sands. The larger the concentration of the particles are, the larger the pressure gradients become. The larger the particle concentration is, the less the effect of particle shape on pressure gradients becomes. The shape effect is greater for the minimum particle transport velocities than for the settling velocities.

Jan 1, 1999

By K. Zabrusky

Estimation of high grade epithermal vein deposits can present challenges in correctly representing the continuity of grade within an undulating structure. One solution to this problem is to use dynamic anisotropy to follow local variations in the strike and dip of veins. Dynamic anisotropy (D.A.) allows the search parameters to change block by block throughout the model to account for the local variations. Presented here is a study of a vein that changes orientation down-dip. A traditional resource estimate using one search ellipse orientation was performed. The resulting estimated grades did not accurately reflect those of the sample data. Using a search ellipse with an average value for the two distinct dips caused the grade estimation to be less representative than desired. Rather than performing domain-based analysis with different search ellipses, the issue was corrected by using Datamine Studio 3?s D.A. function. The 3D vein trend was used to estimate the dip and dip direction of the vein in each block. The resulting D.A.-estimated model follows the two dip trends of the vein. This software makes a previously tedious task faster, and allows for more accurate estimations.

Feb 27, 2013

By Eric Eisold

The Wachovia Headquarters and Arts and Cultural Campus project in Charlotte, NC includes a 1.5 million square foot, 48-story office tower, two museums, an Afro-American cultural center and a 1,200 seat theater for the performing arts. Public access to the Cultural Campus is through two pedestrian tunnels constructed under city streets connecting to parking garages. The 5.7 m wide by 4.7 m high mined tunnels were procured through a design-build contract. The tunnels were designed as initial/final shotcrete linings with a sprayed water barrier sandwiched between layers of shotcrete. In addition, the mix design was supplemented with a cementitious admixture to develop internal water resistant properties in the shotcrete.

You have been involved with research activities in froth flotation and size reduction. What do you think the future holds for these technologies? Froth flotation and size reduction are essential processing steps common to almost all current mineral-processing operations. The most significant recent advances in both of these technologies have been in the increased size of equipment and in some alternative machine designs, such as the column cells and the high-pressure roller mills. I believe that the next major area of improvement in size reduction will be at least partially driven by an improved awareness of controlling the conditions that influence the efficiency of particle breakage. This would include factors such as water-chemistry influences, the influence of fines from classification, chemical grinding additives and better rheology control. In froth flotation, significant changes are currently taking place in the plant use of frothers. Also, there will be an increasing number of new collector chemistries for certain types of flotation, such as with oxide minerals, oxidized mineral recovery in sulfide systems and improved selectivity with certain sulfide mineral systems. You have been active in implementing new engineering technology in industry. What do you think will be the technological future of mineral processing? Being involved in the invention and industrial implementation of new technology has been one of the most positive experiences of my career. I also have had the unique experience of working in the chemical and petroleum industries as well as in mineral processing. In my opinion, the future of mineral processing will be an exciting, wonderful work area in which to be involved. The development of new technology in minerals processing offers a special challenge compared, for example, to that of chemistry or chemical engineering. In successful industrial innovation involving minerals, having a sound theory is not enough. Instead, what is required is a valid blend of a good idea, meaningful laboratory characterization and, most key, the experience necessary to adjust the plant in such a way to incorporate the idea. The complexity of engineering systems that contain solids, liquids and gases, as well as highly variable natural mineral properties, means that nothing new comes easily. In some cases, it has been difficult to explain how processes practiced in industry for decades actually work, in terms of physical and chemical fundamentals. On the other hand, when a new idea is successfully implemented, the economic and professional returns can be very rewarding. I know of no more challenging field of engineering than minerals processing. What is your view of the future of the minerals industry in general? The need for minerals, metals and coal will be with us for decades to come. In many aspects, the minerals industry became global much earlier than some of the other industrial sectors that are currently experiencing globalization. I believe that fair international competition is beneficial to the users of minerals, metals and coals and to those involved in producing such materials. The key word here for a global economy to work is "fair." So the various playing fields involved such as finance, profit return, regulation and labor should be relatively level for all the players involved. Competition is an amazing driving force for innovation. This has been true in the minerals industry during the last few decades. The mining industry is producing more at less cost per unit than ever before in our history. I anticipate that this trend will continue as long as the global political situation remains relatively stable.

Jan 1, 1997

By J. H. Adkins

The goal of the project reported in this paper was to make recommendations for changes in roof bolting procedures and bolter design that would reduce roof bolter accident rates. To that end the project identified the major hazards associated with each task a roof bolter operator per-forms, normalized task accident frequencies. by the time spent on each task, reviewed equipment design features and operating procedures related to the identified hazards and developed recommendations for equipment and procedural changes that would reduce, if not eliminate, the hazards. The research steps completed during the project were: a. A review of related literature and re-search including roof bolting time studies b. The collection and analysis of 1975 accident data pertaining to roof bolter activities c. The normalization of the accident frequency data on the basis of time/task data d. A review of roof bolting equipment e. The development of a field data collection instrument f. The selection of mines for bolter observations g. The collection of field data h. Data analysis and problem specification i. The development of recommendations for corrective measures

Jan 1, 1978

By T. Arthur Palm, Stephen L. Bessinger

San Juan Coal Co. (SJCC) operates an underground coal mine near Farmington, NM. Continuous miners and a longwall produce 6.3 to 7.2 Mt/a (7 million to 8 million stpy). SJCC is owned and operated by BHP Billiton. The coal seam at SJCC has been shown to have a propensity for spontaneous combustion. As such, during the feasibility study for this project, it was elected to use a bleederless ventilation system on the longwall. Due to the combination of spontaneous combustion, methane liberation and, to a lesser extent, hydrogen sulfide, a typical wraparound ventilation system would not be appropriate. Three-entry gate roads are developed, and the longwall gob is sealed as mining progresses. SJCC uses a nitrogen injection system to continuously inertize the gob.

Jan 1, 2007

Mine planners must select a single pit for design with the knowledge that the grades on which this selection is made are uncertain. This uncertainty is often ignored through the use of deterministic models of grade. This makes the mine planner?s job simpler but does not necessarily lead to the ?correct? or ?best? selection. Grade uncertainty is typically modelled with conditional simulation which generates multiple possible realisations of grade that are equally probable (or improbable) to occur. Methods for incorporating grade uncertainty into mine planning to date have either been perceived as being too complicated, not accessible or too time consuming. This paper proposes a simple and efficient modelling approach to incorporating conditional simulation into pit optimisation, which would be able to be applied in currently commercially software. An example for Resolute Mining Ltd?s Syama Gold Project in Mali shows the range of ore, grade and value outcomes associated with generating pits through a variety of methods.

Feb 27, 2013