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The evolution of surface mine layout configuration is a function of the schedules and sequence of material excavation within the optimized layouts. The production schedules and sequence of materials movement from multi-bench and multi-face operations are difficult to plan and execute. However, the ability to maximize the profit or net present value of an orebody is largely dependent on the mining schedule. The mining schedule will determine the life of the mine, the projected cashflows, and the investment requirements over the mine life. The pit geometries, pit expansion rates and the periodic volume of materials from different benches in a multi-bench, multi-face open pit mine determine the equipment requirements. The volume of materials excavated, as well as pit layout changes from circular and elliptical geometries of an oil sands mine were modeled using analytical geometric and parabolic partial differential equations (PDEs) and solved within Matlab. The results show that the geometric values are almost the same as those obtained from PDEs for different pit configurations. The economic analysis shows that both the current mining system (CMS) and the cyclic excavator conveyor belt control system (CycEx CBCS) are viable with high NPV (= $3.20 × 1010), PI (> 19%) and IRR (> 29.02%) with short discounted payback periods (= 3.24 months). The CycEx CBCS option is more economic than the CMS option. Its NPV is 1.27 times that of the CMS option. The PI and IRR for the CycEx CBCS option are respectively 2.24 and 1.13 times that of the CMS option. As well, the CycEx CBCS option has almost half the DPBP of the CMS option. The CMS option has an operating cost of $1.386 per tonne ($2.774/barrel) while that of the CycEx CBCS option is $0.779/tonne ($1.558/barrel). These results show that the CycEx CBCS option is the better option for mining companies working on oil sands deposits to invest in.

Jan 1, 2011

By Donald E. Garrett

Sodium sulfate is one of the larger tonnage industrial minerals. A little more than half of this tonnage — 3 Mt/a (3.3 million stpy) of natural product— is recovered from ore deposits. Most of the rest is produced as a byproduct from other manufacturing operations. Sodium sulfate is mined in a variety of ways. These include conventional room-and-pillar mining, strip mining, in situ leaching of thick ore beds, solar evaporation and cooling-crystallization of lake brine, and the pumping of brine from complex salt deposits. There is also a variety of commercial sodium sulfate ore sources. They include thenardite (the mineral form of sodium sulfate, or Na2SO4), mirabilite (glauber salt,Na2SO4•10H2O), glauberite (Na2SO4•CaSO4), astra-kanite (bloedite; Na2SO4•MgSO4•4H2O), burkeite(2Na2SO4•Na2CO3), sodium sulfate-containing caliche and various brines.

Jan 1, 2002

By Bernhard Leist, William D. Leech, Johann Kröyer, Holger Evers

Landsvirkjun—the national electric power company of Iceland—is building the Kárahnjúkar Hydroelectric Project in eastern Iceland. Two glacial river systems will be dammed and channeled through a series of tunnels into a 690 MW underground powerhouse. The Project has a total of 73 km of tunnels to be excavated of which mosthave been completed. From three access adits, three large diameter (7.2 m to 7.6 m),main-beam, gripper-type, Tunnel Boring Machines (TBMs) are being used to complete50-km of the waterway tunnel. Using the TBMs was a first in Iceland to excavate the complex Icelandic basalt formations, which consist of inclined layers of hard basaltic flows with weaker scoriaceous and sedimentary interbeds. Faults, fissures and dykes that frequently cross the lava flows posed both geologic and hydrogeologic difficulties to the TBM tunneling. This paper describes the extreme challenges that the men and equipment had to endure to complete the tunneling, including the harsh winter weather on the surface and the cold, abundant ground water inflows within the tunnels.

Jan 1, 2007

By D. M. Avant, S. M. Pickering

A variety of grades of very white muscovite mica are now being produced from sedimentary sands and clays in Central Georgia. The mica is naturally concentrated near the base of the lens-shaped kaolin deposits and also disseminated in associated quartz sands. The same weathering and bacterial alteration processes which have transformed the kaolins from dark organic muds to white pigment-grade industrial clays have also removed discoloring iron from the micas and developed unusually white muscovite. Further, chemical alteration has removed some potassium from the muscovite atomic structure, resulting in an easily delaminated mica which can be cleaved to unusually fine, high bulking, high aspect ratio products. The peculiar alteration history of these sedimentary micas enables production of some of the whitest, finest particle size, and thinnest aspect ratio muscovite mica products on the world market today. Raw mica feed is obtained from kaolin and sand processing by-products, and also from beneath the useful base of abandoned kaolin mines. The processed ultrafine and filler grade muscovite mica products are used for paint, plastics, cosmetics, mold release, thermal and electrical insulation, epoxy, and dry wall joint cement markets.

Jan 1, 2002

By Yifan Ding, Shemek Oginski, Patrick Finn

The Manhattan section of the New York Water Tunnel No. 3 constructed by the Schiavone/Shea/Frontier-Kemper Joint Venture is a $668 million project. The contract includes a tunnel drive of 8.85 km (29,045 feet), tunnel lining of 14.77 km (48,468 feet)and construction of nine shafts ranging in depth from 143 m (469 feet) to 169 m(555 feet). Construction methods for excavation of the shafts are presented including raise bore, ground freezing, soil excavation, blasting, slashing, muck handling, rock support and shaft final concrete lining.

Jan 1, 2007

By Ivo Dreiseitl, Kondratenko. Anatoly

"The second prime area within the Interoceanmetal Joint Organization exploration area named H22 was delineated in 2013 with the goal to ensure sufficient nodule reserves for profitable mining operations and processing.The knowledge base for area H22 has been obtained from archive materials. The geological situation can be characterized as follows: the sea bottom is represented by tectonic blocks oriented in a sub-meridional direction. According to swath mapping, the depressions (troughs) are contoured at depths of 4500-4600 m while the tops of horsts occur at 4300-4350 m. Volcanic relief occupies 6% of the H22 area; in the eastern part a multicone volcano was detected. Its area at the base is 153 km2. The maximum height of a cone above the base is 850 m. The crystalline basement composed by tholeiitic basalts of late Oligocene age is covered by about 100 m of sediments. Semi-consolidated to consolidated calcareous nanofossil sediments of the Marquesas formation are deposited on the basement. Higher up in the profile sediments of the Clipperton formation occur. They are represented by unconsolidated siliceous (Radiolaria, Diatom) ooze. Sediments containing calcium carbonate have not been detected. Where opaline silica (or CaCO3 if any) content is below 5%, the sediments belong to zeolitic clays or red pelagic clays. Grain size composition of the seabed and the near-seabed sediments in H22 classifies them into clayey silts."

Sep 1, 2014

A glance at the following chart reveals that because of the continued poor economy, the slump in industrial mineral production continued into 1980. Gypsum was down 17% from 1979; cement down 9%, sand and gravel, 17%, and crushed stone, 11%. All these downward trends reflect the high interest rates and high costs that slowed construction starts. Domestic fluorspar was down 21% and imports off 14% due to the steel iudustry slump. However, potash production was up 8% and phosphate, 5%. Increased drilling activity spurred au increase in barite production of 25%. Most other industrial minerals posted losses with only a few insignificant increases. As expected, prices were higher, reflecting increases due to high costs for labor, supplies, and above all, energy. Increasing energy and transportation costs also had their effect on industrial mineral production. Railroad freight rates increased 16-22% including fuel surcharge; truck rates increased 11-14%a; and ocean freight rates increased 20% for finished goods. The 1979 shortage of boa and hopper cars did not continue into 1980-most likely due to low production of many of the hulk industrial mineral commodities. All in all, 1980 was not a good Year for industrial minerals.

Jan 5, 1981

By Paul Hewitt, Tim Smirnoff

Design and construction of the Epping to Chatswood Rail Line tunnels in Sydney, Australia required an innovative approach to define hydrogeological properties of the Sydney Hawkesbury Sandstone and provided an insight into the hydraulic behaviour of fractured sedimentary rocks. To meet restrictive water inflow and infiltration criteria both the pre-treatment of zones of fractured or highly jointed rock, and waterproofing using an interior spray on membrane for the finished drained tunnels and stations was required. Methods typically used to address the interaction of groundwater and tunnels in the Sydney Basin are demonstrated by case histories from major design-build tunnel projects.

Jan 1, 2005

By M. J. Fairweather, J. R. Egan, W. A. Meekel

Cominco Metals, in cooperation with two Canadian Universities and the Government of Canada, is developing applications for column flotation in the treatment of lead and zinc ores. Plant scale results at Polaris and pilot plant studies of Sullivan, Pine Point and Red Dog ores show column flotation to have significant advantages over conventional mechanical flotation for lead and zinc cleaning. Results from these ongoing studies are discussed in relation to ore texture, mineral recovery, impurity behaviour, scale-up and control.

Jan 1, 1988

By B. Anameric, S. K. Kawatra, K. B. Rundman

The iron nugget process is an economical, environmentally friendly, cokeless, single-step pig iron making process. Residence time dependent process requirements for production of pig iron nuggets at a fixed furnace temperature (1425 C) were investigated. Three chemically and physically different products were produced after complete reduction to iron, depending on the residence time in the furnace. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and pig iron nuggets (PIN). The increase in the carbon content of the system as a function of residence time was detected by optical microscopy and Microhardness measurements. Sufficient carbon dissolution for the production of pig iron nuggets was obtained after 40 minutes residence time. The pig iron nuggets produced had chemical and physical properties similar to blast furnace pig iron. They were liquid state products and slag was completely separated from the metal.

Jan 1, 2005

By R. L. Howell, L. C. Atkinson

Typical sedimentary sequences overlying coal seams consist of interbedded sandstones, siltstones, shales, and rider coal seams. In many surface coalmine settings, these sediments are saturated; and prior dewatering of them is necessary for effective and economic mining, including the stacking of saturated spoils. Such sedimentary sections usually have a very low vertical hydraulic conductivity that does not allow them to drain in a timely manner prior to their being stripped. One potential solution is installation of drainwells. Drainwells are small diameter wells that can collect water laterally from the various more permeable layers in the overburden and then gravity drain it to a lower layer – often the coal seam being mined – where it can be removed by pumping wells or sumps located in the bottom of the pit. A ground-water flow model utilizing the 3-dimensional finite element code MINEDW has been used to evaluate the effectiveness of usingdrainwells in a hydrogeologic setting that is typical of the Powder River Basin. A series of numerical simulations were completed using various combinations and spacings of drainwells and pumping wells to dewater the overburden and coal seams. The numerical simulations suggest that drainwells can be a very effective method of overburden dewatering.

Jan 1, 2000

By C. Sun

The Leeville underground mine has been in operation since 2006 and currently produces 3,500 tons of ore per day with an average gold grade of 0.34 opt. The mine has a large horizontal extent of 2,500 feet by 500 feet and a vertical extent of 20 to 200 feet. Based on the characteristics of the ore bodies, a long-hole stope and cut-and-fill mining methods are used at the deposits which are divided into several mining zones. Cemented rock fill (CRF) is used as the backfill in the open stope. CRF design includes the aggregate design, the ratio of cement and fly ash design, and strengths for the long-hole stope and cut-and-fill. In the aggregate design, the particle size distribution is one of the most influential aggregate characteristics in determining how it will perform as a basic backfill material. Gradation helps determine durability, porosity, cement and water requirements, strength, and shrinkage. To cut the backfill cost, fly ash usually is added into the binder to replace some part of cement. However, adding fly ash can affect the strength of the backfill. The reasonable percentage of fly ash is also important for making a good and low cost backfill. Based on the different mining method, the different backfill with different strength is designed. A systematic quality control procedure for aggregate and backfill is followed. After four yeas application, CRF system in Leeville achieved very good results.

Jan 1, 2011

By A. Ayoubian, V. Nasri

This Tunnel Connection project will include construction of two short tunnels to connect the existing subway tunnels (Red and Blue lines) in the northern loop area of downtown Chicago through a new station. The Southeast Tunnel will connect the Red Line to the new station below the intersection of State and Washington Streets and the Northwest Tunnel will connect the Blue Line to the new station below the intersection of Dearborn and Randolph Streets. The connection tunnels are located in a very dense urban area of downtown Chicago and under several important historical buildings. Both tunnels are curved at the intersections and located at a depth of about 7.5 m below ground surface in saturated soft clay with an average undrained shear strength of approximately 25 kPa. The design calls for minimizing surface disruption and ground displacement while maintaining normal operation of the existing subways during the construction of the connections tunnels. This paper presents mining and cut and cover tunneling alternatives for the project.

Jan 1, 2007

By D. Craig Camp

conditions. The soils included 65 m of rock not exceeding an unconfined compressive strength (UCS) of 200 kgf/cm2, 130 meters of soft clay, silt, and sand not exceeding 30standard penetration test SPT blows per 300 mm, and 220 m of rock ranging between an UCS of 400-600 kgf/cm2. The river crossing, utilizing 1778 mm OD x 19 mm wall x600 mm steel casing pipe without intermediate jacking stations, was part of a seven kilometer liquefied natural gas (LNG) transmission line in South Korea. This 440-m, 1,442-ft, river crossing was microtunneled through three different ground conditions and completed in just over three months. The crossing was achieved with an average of 25 m of ground cover and 15 m of water cover. The Kwang Yang River Crossing was part of a 7 km liquefied natural gas pipeline project for POSCO, a Korean steel producer. The microtunneling machine was custom built for this project. The microtunneling machine selected for this project was tooled with 7 button bits and 2 roller bits. None of the cutter bits were replaced during the drive. Inside the machine, before the spoils laden slurry was pump back to the surface, it would pass through an independent cone crusher. The crusher is placed in the slurry flow to make sure that none of the spoils are so large as to stop the return flow of the slurry. An additional requirement was for the inclusion of a compressed air lock. The air lock was required in the event that the cutter tools required replacement. The cutters were back loaded so that the workers would have access to change the cutters in the event of cutter failure or wear out. No intermediate jacking stations were installed for the drive. The soils included 65 meters of rock not exceeding an unconfined compressive strength (UCS) of 200 kgf/cm2 with production averaging between 7 and 20 mm/minute. The second zone contained 130 meters of soft clay, silt, and sand not exceeding 30 standard penetration test (SPT) blows per 300 mm with production averaging between 80 and 180 mm/minute. The third zone contained 220 m of rock ranging between an UCS of 400-600 kgf/cm2 with production averaging between 7 and20 mm/minute. The steel casing pipe was 1778 mm OD x 19 mm wall x 6000 mm long. The project profile, see Figure 1, shows the soil conditions. The hand written numbers locate just above the pipeline are the production dates. The circled numbers are the 10 pipe joint increments. The project required 74 pieces of pipe to span the440 m drive. Figure 2 and Figure 3 are the jacking information. Figure 3 is a continuation of the information from Figure 2. The top section of the graph is the jacking force. The jacking

Jan 1, 2001

By X. Zhou

In this study, the cyclonic static microbubble flotation column (FCSMC) was investigated for fluorite beneficiation. The structure and principle of the specially designed column are described. Fluorite samples from the tungsten separation tailings of the Shizhuyuan Mine, Chenzhou, Hunan Province, P.R. China, were tested using a small-scale continuous flotation test unit, and concentrates with a fluorite grade higher than 98% were obtained. One rougher and three cleaner stages in the FCSMC achieved the same separation performance as one rougher and eight cleaners in conventional flotation cells. This greatly simplified the flotation circuit and reduced operating costs.

Jan 1, 2007

By A. Fred Gelding

Introduction In preparing this paper considerable time was spent attempting to find some upbeat data about the mining industry, so those of us in the field could feel somewhat better about future prospects. Much to my regret, I failed to uncover substantial evidence that our near-term or, for that matter, our long-term opportunities appear all that bright in North America. That is certainly not the kind of assessment anyone likes to hear or accept as even a possibility. Those remarks may, on the surface, appear far too pessimistic. This industry will experience a recovery and most likely will see conditions begin to improve later this year or early next. The kind and degree of recovery, however, will more than likely differ from those experienced in the past. Fundamental Changes Clearly, the fundamentals on a world scale of our business have undergone important changes. In recognizing these fundamental changes, mining authorities believe productivity advances are needed to change the direction mining has taken in recent years. The really tough question is whether increases in productivity will be enough to change the course of events that has dominated the mining sector for the past decade. Before one can provide an honest answer, an appraisal of what has and is happening now is necessary. Here are some changes and events that have taken place that effect domestic mining and will probably continue: • Mineral-rich lesser developed countries (LDCs) in Africa, South America, and Asia-Pacific have reached a point where they have developed the needed mining infrastructure to not only produce at a high rate, but in many instances, at a lower cost than fully developed countries. Just as importantly, these countries, even if they do not enjoy lower costs, will produce for world export with government subsidies because min¬ing products are key in obtaining badly needed foreign exchange. • These producing countries also have the distance advantage of lower labor, environmental, and other important regulatory costs. If that were not enough, these same countries have minerals with considerably higher grade ore and, in some cases, much lower cost accessibility. • Exporting North American commodities is impaired by a dollar that continues to strengthen against other important currencies around the world. There are other impediments to overcome, but these represent some of the realities our industry faces. Can those obstacles be overcome through improving productivity? In the past, this industry has offset the impact of these events to a sizeable degree through innovations of mining techniques, equipment and processes, and by increasing the size of its individual operations to reduce costs. Will further enhancements along these lines be enough to alter this changing balance in the future? While there is no answer, it is apparent that if we do not mount a full-scale assault in some key areas, our prospects will not be encouraging. Productivity improvements throughout the entire chain of the mining industry most certainly rates as a high priority. Every link in that chain from mine planning, equipment selections, and transportation considerations needs to be examined and reexamined to assure the lowest effective cost is developed. Quality, while oftentimes costing a little more initially, is still the most cost effective purchasing decision to make. Regulations Another area of concern is regulations, be they environmental or those that dictate what must or must not be done in running our business. Certainly, I do not suggest that we not protect our environment. However, there is an acceptable balance that has, over

Jan 11, 1983

By O. A. Bascur

The lack of integration of mining and metallurgical information with sufficient detail for analysis causes inefficient operation and hence sub-optimal energy and water use. It is difficult to analyze the performance of mining and metallurgical processes without an integrated view of mine transactions, stockpile inventories, process flows and assays. To take action requires real time information from manufacturing assets, corrected for gross errors from trucks, shovels, conveyors, faulty sensors, bad instrument calibration. This paper presents an infrastructure with advanced tools that sift through available data, identify and eliminate gross errors, and transform the data into business information for continuous improvement and optimization. Collaboration is a key component of improving efficiency of energy and water use, and the evolution of Web technology enables collaboration and troubleshooting of plant information to more quickly act on issues to reduce wasteful operation. Keywords: Mine Concentrator Optimization, Real Time Performance Management, Data Unification, Integration of Operational and Business systems, Mass and Energy Balances, Real Time Web Services, Equipment Availability, Efficiency.

Jan 1, 2009

By R. Kaushik

According to the U.S Department of Energy (DOE), mineral processing activities including comminution (size reduction) uses 4% of the world electrical energy consumption. Such numbers reinforce the need to invest in energy savings initiatives in order to produce more using less. ENERGY EFFICIENCY OPPORTUNITIES AND CHALLENGES IN MINING OPERATIONS In addition, DOE, in its Mining Industry Energy Bandwidth Study, has identified huge potential for energy savings for the coal, metals and mineral industries. Even knowing the overall causes of energy waste and some potential tools for remediation, mining companies may struggle to apply such tools and get the desired results due to the following reasons: ? Limited staff ? Lack of accurate economic and investment analysis to justify energy savings projects ? Lack of knowledge to identify low or no-cost savings opportunities ? Internal competition for resources According to the workforce and talent management experts, the Talent Strategy Advisors, the demand for mining engineers is expected to exceed supply by 30% by 2013. Mining personnel are likely to be burdened with increasing and varied workloads with limited training. This will result in the need for automated and simple tools to support energy efficiency activities. Mining engineers will simply not have the time and resources to create such tools, collect and analyze the data to make decisions, and track results.

Feb 27, 2013

By G. S. Takenaka

When Bridger Coal Company transformed their operations from surface mining to an underground longwall operation their plans included not only the addition of new mining equipment but also surface fans for a blowing (supply) air ventilation system. The original system concept included a propane gas fired air heater to preheat the intake air during cold weather and a dual parallel fan and duct system. One fan operated to ventilate the mine while the other fan was for stand-by emergency operation. Equipment proposals were submitted in March, 2005 based on the dual parallel fan system. Discussions conducted during the equipment selection process revealed that several alternative system design concepts were available. The alternative concepts included innovation features that not only saved space and cost but also reduced operating expense as well. Many of the features were incorporated into the final design of the system. A comparison of the original system concept and final installation design are presented in the paper in addition to details of the features and the derived benefits.

Jan 1, 2009

By David M. Jurich, Randy J. Essex, Alex de Aboitiz

An Automated People Mover (APM) transit system is planned for the growing Phoenix Sky Harbor International Airport. The APM will improve passenger movements between the terminals, and provide a link to parking facilities, a new rental car facility, and the planned metro Light Rail. The underground works will include shallow twin bored tunnels, taxiway crossings, and underground stations constructed beneath critical airport facilities. Challenging soft ground conditions will require extensive underpinning and ground improvements. Design is underway, and construction is scheduled to begin in 2007 with project completion in 2015. The owner’s planned delivery method for the APM Project will be Construction Manager at Risk (CMAR) with a Guaranteed Maximum Price.

Jan 1, 2005