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By Peter White

A bridge reconstruction project involved driving pipe piles for the new foundations. Disturbances within soil layers at depth caused sinkholes to open up within the construction site. After a near fatal accident, the pile driving installations were suspended. The solution involved ground im­provement through cement grouting with sleeve pipes and special grout additives to minimize migration of cement grout.

Jan 1, 1997

By D. Küster, G. Franken, P. Schütte, J. Vasters

The CTC (Certified Trading Chains) mineral certification system has been piloted in Rwanda since late 2008. CTC project implementation is jointly driven by the Federal Institute for Geosciences and Natural Resources (BGR) and the Rwanda Geology and Mines Authority (OGMR), in cooperation with other national stakeholders. Five Rwandan mineral producers participate in the CTC project with their flagship mining concessions. Based on independent third-party audits, CTC certifies supply chain due diligence measures of these companies engaged in the artisanal mining sector through on-the-ground assessments of mining conditions, transparency, as well as mineral origin and traceability. The CTC system thus allows responsible mineral producers and their clients to verifiably demonstrate supply chain due diligence and good governance in conflict-affected and high-risk areas.

Jan 1, 2011

By Z. Y. Ding

This paper emphasize two points in piled wharf design which are important than structure calculation. First, during design of piled wharf on soft stratum, the bank slope stability is the first important item. Second, the live load, the backfill and the original ground's settlement will influence the wharf structure causes cracks. Two practical examples were illustrated.

Jan 1, 1991

By Steve Kral

Globalization was the key word for the mining industry during the 1990s, just as productivity was the key word of the 1980s. And globalization will remain the key word as the industry enters the 21st century, according to speakers at the Colorado MPD Meeting held in Colorado Springs, CO in May. The meeting, put on by the Colorado Section SME Minerals Processing Division, drew about 120 people to the Broadmoor Hotel. “Operating Globally” was the theme of the 49th annual conference. Speakers addressed the reasons why mining companies have limited their spending in the United States and have moved into Third World and developing nations.

Jan 1, 1999

By Remo Grandori

The Umiray Angat 13,2 km long tunnel in Philippines have been bored through extremely variable and difficult ground conditions including a number of special events. In particular the following adverse conditions were found: faults in decomposed ground, high temperature rocks, extremely rapid and important convergence phenomena, water inflows up to 800 litres per second. The special El Nino climatic conditions caused a long dry season and lower the level of the lake that was granting the access by barge to the site under the minimum navigable level. Many equipment have had therefore to be transported to site by a 10 ton capacity helicopter, after having been partially dismounted. For the same reason most of the tunnel drive have been bored servicing the site by 1 ton capacity helicopters to transport materials, spares and personnel. In order to overcome the above geological and logistic problems several innovation were introduced and tested in this project. Despite all that difficulties the 13,2 km of tunnel were bored in about 24 months, with a global average of 500 m/month.

Jan 1, 2001

NIOSH research has focused on the monitoring and the control of methane levels in active mine workings. Response times for instrumentation using catalytic heat-of-combustion sensor technology were evaluated. NIOSH research has modelled the flow of methane gas onto long-wall faces and gobs, developed engineering controls to limit methane levels during mining, and designed coalbed and gob degasification systems. Available methane control systems have been challenged by recent developments in longwall and room-and-pillar mining systems. This includes increased face advance rates leading to increased productivities, increased longwall panel sizes, and the generally deeper workings of U.S. coal mines. The potentially violent nature of any underground explosion or ignition requires the measurement, control, and reduction of methane emissions into the mine environment for continued worker safety.

Jan 1, 2008

By Jeff Kravitz, John Kovac, Wayne Duerr

Since 198 1, Federal mining law has required every miner working in underground coal mines to have a self-contained, self-rescuer (SCSR) available for use in emergencies. Some miners that have escaped from fires using SCSR's have reported that they had to remove their mouthpiece to talk during escape, thus compromising the protection afforded by the SCSR. If miners are in thick smoke during an escape, they may have trouble if they become separated from their group. The visibility can be so poor that separation can occur at very short distances. To address this problem, two-way, FM radios were built into the SCSR to improve the ability to communicate should the miners be separated over relatively short distances. The SCSR prototypes built and used in testing included both two-way radios and improved mouthpieces. Comparison studies were conducted using combinations of the new and old mouthpieces, and trials using the radio or not using the radio. Subjective judgments indicate that communication ability was significantly improved using the prototype devices. Communication problems have been encountered with teams using standard voice- powered communications systems. Mine rescue teams perform rescue and recovery work under extremely hazardous conditions, life lines are a standard part of mine rescue team equipment. Leaky feeder and quasi-leaky feeder life line communications systems provide significant improvements over standard systems. These improved systems allow all members of the team to communicate with each other and their base of operations. These innovations will significantly enhance the safety of mine rescue operations.

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By W Valery, S Morrell

In the mining industry blasts are usually designed to fracture the in situ rock mass and prepare it for excavation and subsequent transport. The run of mine (ROM) fragmentation is considered good when it is fine enough and loose enough to ensure efficient digging and loading operations. Mining optimisation strategy is hence usually focussed on minimising total mining costs and maintaining these ROM fragmentation characteristics. Although this approach ensures an efficient mining operation it ignores the potential impact on crushing and grinding. Investigations by several researchers have shown that designing blasts to produce ROM fragmentation to optimise crushing and grinding performance enhances the overall efficiency and profitability (Eloranta, 1995; Kojovic et al, 1995; Bulow et al, 1998; Kanchibotla et al, 1998; Scott et al, 1998; Simkus and Dance, 1998). Field experimentation in this area is often found to be difficult because of high implementation costs and insufficient understanding about the effect of fragmentation at different stages in a comminution circuit. Modelling and simulation of blasting and comminution processes provide a more economic alternative to explore the impact of blast design changes on the down stream operations (Kanchibotla et al, 1998; Kojovic et al, 1998; Adam and Siddall, 1998; Bulow et al, 1998). However, the reliability of such simulations depends on:the ability of the models to reproduce the physical processes that take place; characterisation of rock mass in terms of its blastability and comminution characteristics; and in the case of blast modelling the ability to predict fines (-10 mm) has been found to be particularly important as this fraction has a significant effect on mill throughput.

Jan 1, 1999

By X. Shi

This paper presents design and implementation details of a fuzzy-behavior-based controller for an automated excavator. The robotic excavator is equipped with sensors, actuators and an embedded control system. The excavator controller uses neural-networks to interpret forces and torques gathered during the excavation process from bucket-mounted force sensors. Implementation details card experimental results using the fuzzy-behavior-based excavation controller are given for several excavation tasks. These excavation tasks demonstrate some of the complex skills that are essential for an autonomous mining-excavator controller.

Jan 1, 1997

By J Parnell, B Manson

Bitumen occurs in the basins in reservoir sandstones, in veinlets close to hydrocarbon source rocks, in veins through lava beds and in sulphide-mineralised veins where it is closely associated with, but predates, the sulphides. The role of organic matter was probably in enhancing metal reduction by creating a low-Eh environment rather than in metal transport. Coeval euhedral quartz crystals or albite in sulphide-bearing carbonate veins provide evidence of an aqueous component to the hydrocarbon fluid

Aug 1, 1995

By Christophe Bragard, Brett Robinson

This paper reflects the challenges encountered during the construction of the light rail tunnels under Boyle Heights, in Los Angeles, California. Equipped with two state-of-the-art EPB TBMs, the construction team undertook the mining of twin bored tunnels in the Los Angeles alluvium. The gassy underground conditions dictated many aspects of the design of the tunnels, as well as the tools and means used for their construction. This paper will detail the challenges encountered during construction, as well as the means, methods and logistics used on the project. Discussion includes: EPB TBM machines with some very unique/specific features; complex assembly sequence due to limited shaft access; final precast concrete liner with double gaskets; NATM cross passage excavation in soft ground and below the water table; compensation grouting; mucking shaft arrangement.

Jan 1, 2007

By A. F. Banks

"Potash processing in Canada commenced on a commercial scale in 1962. Over the last 25 years it has grown into a world-class industry with many advances in processing technology. As it is a relatively young industry, many more advances can be expected. Unlike much of the mineral production in Canada, potash is sold as a range of finished products. The processing involves potash recovery and finishing in about equal amounts in terms of the effort of processing. Environmental concerns are not insignificant and are being treated uniquely in some areas. Research and development efforts, while not carried out on a large scale, are attacking industry problems on a wide front.THE INDUSTRYThe Canadian potash industry has 12 producing mines, 10 in Saskatchewan and 2 in New Brunswick. The total productive capacity of the industry is 18,300,000 tonnes of products per year. At capacity, the industry 1•ill process the equivalent of about 53,000,000 tonnes of ore per year. Plants range in size from 8,000 tonnes to 24,000 tonnes of feed per operating day. In product terms this is from 2,500 to 3,500 tonnes of products per day.Of the 12 mines, 11 are conventional underground mining operations with potash recovery principally by flotation supplemented by crystallization and one is a solution mine where mining is achieved by dissolving the potash and salt in underground caverns and then treating the solution in an evaporator/ crystallizer circuit. In all plants there is commonality of unit operation in the product screening and compaction sections. There are three principal ores being treated in the conventional plants. These may be characterized in general terms as follows:"

Jan 1, 1987

By Boden A

A procedure was developed for recovering metal values from copper-smelter fume. The fume is first leached to neutrality with dilute sulphuric acid to obtain a solution of zinc sulphate containing a low level of impurities. The tailings from this leach are treated with hydrochloric acid in two stages, in which tin and zinc are quantitatively leached and recovered as a tin concentrate and a zinc sulphatelzinc chloride solution.About 80 per cent of the lead sulphate is converted into lead chloride, which can be recovered as a pure product.Data on the effect of temperature, acid concentration, aeration, and solid/liquid ratios on the hydrochloric acid leach are presented, and the fate of the most important metals during the recovery process is described. Alternative treatments of the tailings from the neutral sulphuric acid leach were briefly investigated.

Jan 1, 1977

Mine ore, reduced to minus 71/2 in. by primary crushers, is stockpiled. Size reduction of the reclaimed material by secondary and tertiary crushers is achieved in a closed circuit crushing and screening plant. Screen products of minus 30 mm plus 6 mm lump, and minus 6 mm fines are stockpiled by conveyor and stacker systems prior to rail despatch 10 port facilities at Dampier. Crusher settings, determined from experience, are closely maintained to obtain the desired lump/fines ratio. Chemical and sizing analyses from automatically taken samples are used to maintain product specifications. The beneficiation plant upgrades the fines product when this is necessary. The recorded wear life of individual plant components is the basis of a planned maintenance programme.

Jan 1, 1970

By B. Beatty

Discussion by B. Beatty This is a response to M.J. Hrebar's paper, which tracks in detail the highly productive stripping capabilities of modern large bulldozers at two separate installations. It proves the old adage "economies of scale" and quantifies the advantage of being able to move large loads of dirt over comparatively short haul distances by sliding rather than carrying the load. This discussion examines whether a bulldozer is the most efficient way of using this geotechnical principle. Case 1 - Study eastern US: Contour coal stripping application The energy consumption for the Case 1 mining method (eastern US contour stripping operation) shows the D11 averaged 117 L (31 gal) of diesel fuel per scheduled hour, and produced 333.3 bank m3 (436 bank cu yd) per scheduled hour (0.351 L/m3). Assuming 1 L (0.26 gal) of diesel fuel contains 10.4 kW-hr of energy, the unit expenditure of fuel energy for Case 1 Study was 3.66 kWh/m3. Another way of shifting this material is by using an overburden slusher (OS), as shown in Fig. 1. The OS as shown in Fig. I. The OS is electrically powered and consists of a manned low wall winch (LW ), a remote controlled (radio telemetry) highwall winch (HW) and a hoe. The winches operate to pull the hoe back and forth across the pit. The hoe carries load in the forward direction ahead of a rear mounted blade and returns empty. A spreadsheet (Lotus 123) simulation package, BOSSIM, models the OS operation on a load by load basis over a wide range of pit configurations. The geometry shown in Fig. 2 of the paper was modeled using BOSSI M and the results are summarized in Table1. Table 1 shows a LW with 150 kW (200 hp) and a HW of 120 kW (160 hp) installed power, towing a 15-m3 (19-cu yd) hoe, would accomplish the Case 1 stripping task at about the same scheduled stripping rate (D11=333 m3/hr or 433 cu yd/ hour, OS=342 m3/hr or 447 cu yd/ hour). It was assumed the winches in this equipment have an electromechanical efficiency of 90%. This gives an average electrical energy expenditure rate of 151 kW-hr, and a unit energy expenditure level of 0.44 kWhr/m-3(0.57 cu yd/kWh)-an improvement of 8291%- over the D11 alternative. The energy comparison illustrates the importance of using more efficient electric power if possible, ahead of the internal combustion engine, and delivering power from a fixed ground position rather than through a moving track system. Another important energy observation is the comparative action of the dozer blade and the OS hoe. The former implement continuously digs and spills as it works the load forward. The OS hoe digs the load until full, the blade then lifts due to the contained load pressure and a shear plane forms under the mass, enabling it to slide forward in a force reduced - transporting mode. Economic comparison Table 2 operating cost per scheduled hour and unit cost comparison follows a format used in Tables 2 and 3 of Hrebar's paper and compares Case 1 Study with the OS alternative. Drill and blast costs are kept constant in both cases, although when larger OS units are considered, it is expected these costs will reduce because bigger hoe sizes will permit larger rocks to be transported efficiently.

Jan 1, 1995

New Zealand has been a significant producer of gold for over a century. Total recorded production is over 850 tonnes. There were three major periods of production: the first and biggest was between 1860 and 1880, the second was between 1895 and 1920 and the third was between 1930 and 1945. After 1945 gold production fell continually until 1980 when the major upward adjustment in gold price led to renewed interest. There have been important new developments in each of the known gold-rich areas: Westland, Otago and Coromandel and exploration for gold in these areas and in previously unprospected regions has reached unprecedented levels.

Jan 1, 1988

By Michael Lane

With the success of their existing casino operation on the Ohio River in Lawrenceburg, Indiana, the Indiana Gaming Co., LP planned a major expansion of the current facilities. This expansion includes a second 1400+/- car parking garage, a new surface parking lot, elevated walkways, and a new floating casino that will double their present square footage and consolidate all of the gaming activity to one floor. In March of 2006 Richard Goettle, Inc. was awarded the general contract to construct a 260? x 520? boat slip for the new Argosy VII floating casino. An Open Cell® bulkhead system was specified as the means for constructing the new slip. Our contract included the purchase and installation of 300,000 square feet of PS27.5 sheet pile, excavation of 230,000 cubic yards of soil, and a 3300 square foot Mechanically Stabilized Earth wall.

Jan 1, 2008

By F. Lindroos

A cornerstone in the LKAB Green Pellet concept is to produce pellets with a small footprint in terms of energy con-sumption, CO2 emission and emission of other elements harmful to the environment, like dust, sulphur dioxides, nitrogen oxides, chloride and fluorine. The concept also encompasses our determination to make pellet products that contribute to low environmental impact and low energy consumption in our customer?s processes. The presentation will focus on the pelletizing process. It will describe both how we have attempted to decrease the generation of unwanted components in the process gas, and how we have tested or evaluated equipment for external gas cleaning. We will discuss and give examples from recent and on-going efforts and outline some of the future challenges we see, to meet our own environmental standards and also the tough demands imposed by EU and national legislation, while striving to boost production.

May 1, 2011

By Kira Mizell, James R. Hein, Tracy Conrad

"The Ninetyeast Ridge (NER) extends roughly N-S as a topographic feature for 5000 km, from 31° south to 10° north (Fig. 1) where it becomes buried beneath the Bengal Fan at its northern end. These two geographic characteristics make the NER an ideal natural laboratory for determining the influence of latitude and terrestrial input to ferromanganese (Fe-Mn) crust formation and composition. In addition to study of geographic controls on crust composition, the NER is the largest feature in the Indian Ocean that may host crusts of economic interest.Crusts were collected from 9 of 33 dredge sites from 1.4° north to 26° south latitudes during the 2007 R.V. Roger Revelle Knox06 cruise. Nineteen samples were analyzed for 69 elements each. Nine bulk crusts and 10 layers from four crusts were analyzed. Three of the crusts sub-sampled for layers did not have the bulk crust analyzed and the weighted means for those layers were calculated to obtain bulk compositions. One sample was left out of the statistical analyses because it is phosphatized and chemically quite different from the other samples (Table 1).In order to determine changes in composition with latitude, Pearson product-moment correlation coefficients were calculated for the chemical dataset and latitude of dredge sites, as well as water depth. At the 95-99% confidence level, the following elements increase in crusts moving north along the NER: Mg, Ti, S, Cd, Ni, Tl, Mn, Ba, Co, Cu, In, Li, and Zn; and the following elements decrease northward: Fe, Fe/Mn, P, As, Sc, the rare earth elements plus yttrium (REY), Bi, Ge, and Pb. These correlations indicate that the iron oxyhydroxide component and its associated elements are more prevalent to the south, and the manganese-oxide phase and associated elements increase toward the north end of the NER. This change occurs between dredges D20 and D14 (Fig. 1), with crusts from D20 and south having Fe/Mn !1.0 and those north of D20 ""1.2, with the exception of the phosphatized crust. Crust composition also changes with water depth: Th, Ge, Pb, and the middle rare earth elements (REEs) increase with increasing water depth. Thorium commonly increases in deeper water crusts, which explains the higher Th concentrations in Atlantic and Indian ocean crusts in general compared with Pacific crusts (Fig. 2 and Hein et al., 2012), including the samples analyzed here with a mean water depth of 3584 m. However, water depth does not explain the latitudinal changes because the mean water depths of samples along the northern and southern segments of the NER are roughly comparable. Surprisingly, Si and Al, representing the aluminosilicate/detrital phase, do not correlate with latitude; that is as the ridge approaches and is buried by the Bengal Fan the Si and Al contents do not increase. However, overall, Si and Al have higher concentrations in NER crusts than in central Pacific crusts. Ba can be used as a proxy for primary productivity and statistically does increase to the north along the ridge in the direction of the equatorial zone of high biological productivity. Correlations of Mg, Li, and Zn with latitude may also reflect increased primary productivity at lower latitudes."

Sep 1, 2014