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By J. G. Henning

Following completion of planned mining operations at the Goldcorp Dome Open Pit Mine, a high-grade Shaft Pillar located in the pit highwall was recovered. Mining of this Shaft pillar faced numerous rock engineering design and implementation challenges due to its remote position on the highwall and the presence of mine workings within the wall. The case example presented in this paper discusses the geotechnical investigation performed at the site, novel measures undertaken for installation of ground support required for rockmass reinforcement and for worker protection, as well as operational challenges to successful mining of the Shaft Pillar.

May 1, 2009

All development proposals have to run the gauntlet of the approvals process. Major resource projects are generally subject to particularly intense scrutiny. The key element in the approvals process is that it is about making decisions that take into account the benefits or otherwise to society as a whole - the interests of any one group do not take precedence. Most groups tend to see their relatively narrow interests as representing those of the broader society. Each group develops their arguments for or against a project in isolation, and then presents these to an arbiter in an adversarial situation. From this mire of argument and counter-argument it is often difficult to discern just what the real benefits of a project are, and opportunities for agreement and constructive modification of proposals to meet real concerns are often missed. The contention made in this paper is that the inevitable differences between these various viewpoints should be harnessed to help the proponent to come up with a proposal that is clearly of overall benefit to society and which gains approval. It is better to accept that no one group has a monopoly on wisdom in this area and to engender an environment of creative tension in which the pros and cons can be broadly considered and good planning and design used to produce a proposal that has a high chance of success. There are a variety of ways in which this approach can be implemented. Some of these options will be discussed in terms of their likely applicability to energy projects and their potential for success.

Jan 1, 1992

By R. Adsero

The analysis of equipment trends in AUSIMM?s Revision of Monograph 19; Australasian Mining and Metallurgy Operating Practices (AMMOP) in the paper by Dight et al (in press) raised some interesting and in parts disturbing trends in the Open Cut Mining Industry. According to the US Bureau of Labour Statistics the US mining and petroleum industries? productivity is down by 12% since 2004 while the Australian Bureau of Statistics shows the productivity of the Australian mining industry is down by 34% since 2001. In terms of open cut equipment median output for draglines is down by 15% since 2003; electric rope shovels are down by 41% since 2003; hydraulic excavators are down by 39% since 2008; front end loaders are down by 39% since 2007 and trucks are down by 41% since 2006. Clearly the boom has not been good for the efficiency of the mines. During this same time, best practice (defined as the average of the top 10% by annual output per unit of input) has declined but not by as much as the median (eg. shovels down by 8%, excavators down by 19% and FEL?s down by 5%). This paper will build on the analysis of AMMOP to understand the differences occurring between median and best practice and identify the factors contributing to the decline in performance. As the industry enters a period of potentially lower prices for commodities and reduced margins pressure will be brought to bear on mine sites to start moving more with the equipment they have. An understanding of where efficiency has been lost will be a key component in that. The information contained in AMMOP, and the subsequent analysis of that information in papers such as this one will be crucial to reversing the decline in open cut equipment performance.

Feb 27, 2013

By D. A. Buckingham

Engineering and economic evaluations were performed by the Bureau of Mines on 14 Frasch sulfur, 1 native sulfur, and 21 metal sulfide operations in 11 market economy countries. The evaluation included discounted-cash-flow rate-of-return economic analyses at 15 pct to determine the average total cost of production of these two commodities and the potential availability of elemental sulfur (8) and pyrite concentrate. The Bureau evaluated the potential availability of elemental sulfur and pyrite concentrate. Approximately 279 million metric tons (Mmt) of pyrite concentrate at 46 pct 8 is potentially recoverable from 422 Mmt of in situ metal sulfide ore. Nearly 89 pct of the total pyrite concentrate is available at an average total cost of production below the January 1984 pyrite concentrate market price ($43/mt). About 185 Mmt 8 is potentially recoverable from 253 Mmt of in situ elemental sulfur. About 99 pct of this sulfur is available at an average total cost of production below its January 1984 market price ($131/mt).

Jan 1, 1986

The use of scrapers in mining and earthmoving operations is not new, in fact they are one of the earliest methods of bulk earthmoving. A single machine which can load, haul, and dump material with a minimum of ancilliary support is a highly productive and cost-efficient method of earthmoving. In recent times scrapers have been unpopular due to perceived problems and operational limitations, but the last couple of years have seen a resurgence in the use of scrapers in the Bowen Basin as a primary prestripping tool. The main operational limitation of scrapers is the economic operating range. maximum productivity and lowest cost per bcm is achieved on short leads, as the lead distance increases the cost per bcm quickly reaches and then overtakes that of an truck-excavator fleet. The geometry of a ætraditionalÆ coal mine does not readily allow short leads for prestrip fleets due to the nature of dragline stripping operations. The strip arrangement means that material has to be taken around the end of the pit, meaning a longer haul distance than the actual point-to-point distance between load and dump. This can be alleviated by using pit bridges, however these can cause spoil problems for draglines if not properly planned and have been avoided by many mines. Due to the economic haul distance limitation of scrapers, truck-excavator fleets have become the normal method utilised. Currently more geologically complex mines are opening up, which do not allow traditional down-dip strip mining to occur. Cross-dip mining methods allow for short leads between prestrip loading and dumping areas, hence scrapers and bulk doze are realistic alternatives to a truck-excavator fleet in the prestrip environment. Keeping the lead distance to a minimum a fleet of 657Æs can move material at a very low cost. The other main operational limitation of scrapers is the type of material that can be economically excavated. Hard material can lead to damage to the bowl, free-flowing sand will not readily stay in the bowl leading to reduced load factors. Ripping the material with a dozer prior to excavating can lead to improved loading time, and greatly reduced GET consumption. When considering scrapers for prestrip operations a number of things must be considered: is the lead distance within the economic haul distance? should twin power (push-pull) or single power (dozer pushed) scrapers be used? do I need to rip, what should I rip with? what ancilliary support is required? is there another system already available on-site which is currently under utilised? This paper considers the parameters under which large twin power scrapers are the most effective way of undertaking prestrip operations.

Jan 1, 2003

By P. Grainger, P. G. Kalaugher

Paper presented at conference and first published in preprint volume of: Risk assessment in the extractive industries, held in University of Exeter, 23-24 March 1994. London: IMM, 1994. Large, unpredicted ground movements resulting from open cast or underground mining present risks to the safety and economy of extractive industries. As large, sudden failures are usually preceded by small displacements at a much slower rate, the detection and monitoring of these minor changes to the ground surface provides a means of assessing the risks. It is recommended that a visual approach is often preferable to surveying or fixed instrumental measurements. An optical system has been devised, incorporating a 35 mm camera, which allows an immediate comparison on site between a colour transparency taken on a previous inspection and the scene it represents. The observer fuses the transparency stereoscopically with the directly viewed scene. The impression is close to that of normal vision except that differences in detail which have occurred since the transparency was taken are immediately obvious, enabling a qualitative assessment of changes to be made on site. If repeat photography is required it can be taken with exactly the same alignment and coverage. The two images are then available for office analysis using simple micro-photogrammetry

Apr 1, 1996

By Paul M. Wiltcher

This paper discusses how benefits in engineering design can be achieved from combining existing GRP concrete design guidelines with carbon steel design codes primarily made possible due to the increase in the constitutive properties of modern composite rebar or GRP. It also examines the technical and practical considerations necessary to both construct and ensure the integrity of composite rebar during transportation and handling on site and the measures taken by Franki-Cementation Joint Venture to ensure the safe deployment of the GRP in the workplace on the Noord/Zuidlijn Project in Amsterdam between 2003 and 2006.

Jan 1, 2006

During recent years there has been a marked increase in the use of explosives in Queensland coal mines. Delay detonators have been introduced and their use has extended with the wider application of mechanised methods of mining.The need for careful study of the characteristics of delay detonators is stressed so that the advantages of simultaneous firing, from the points of view of safety and efficiency, may be obtained. With their use new potential hazards are introduced. These hazardsare considered and means whereby the overall safety may be improved are discussed.The increase in the number of misfires since the introduction of delay detonators is shown and the examination of misfired detonators is described. Lessons to be learned! from these misfires are noted and details are given of the essential requirements for safe and efficient blasting using delay detonators.INTRonUCTIONOne of the aims of mechanization in coal mines is to reduce the physical effort applied to the winning of coal. Explosives play an important part in achieving this and, following the introduction of power borers for the drilling of shot-holes in Queensland coal mines, much of the arduous work associated with coal getting has been eased. During recent years there has been a marked increase in the consumption of explosives, as shown in Table 1, and it must be the aim of all to use these explosives safely and efficiently. That there are dangers associated with the use Of explosives cannot be denied. The shotfiring operation is fully covered by legislation and, being under the control of one man, shQuld be capable of being carried out with a high degree of safety. The main source of accident appears to be the failure to take proper cover and this has resulted in...

Jan 1, 1958

Coal has become an enormously important export industry. Owing to a range of mainly natural advantages, Australia has been able to almost treble its exports in a little over the last decade. Australia is now the world's second largest exporter and coal is now the nation's largest single export earner.Despite this very significant growth, Australia's competitive position is in jeopardy.

Jan 1, 1984

By Mikhail P. Nesterov

The paper presents the results of the research that can forecast the development of subsidences and deformations of the earth surface with time in the permanent marginal areas of the movement troughs arising when mining sylvinite beds in the Upper Kama deposit of potash ores where the rock formation support is made by means of interchamber (rib) pillars of various yieldability.

Jan 1, 1997

For the purposes of this discussion it is assumed that contributors should express the thoughts that arise from their personal experience. So wide is the range of mineral deposits, and so varied the methods employed in their discovery and development, that no two geologists are likely to have been impressed with the same applications of their science. The author's own personal experience has been, during recent years at least, very largely concerned with the broader aspects of the employment of scientific method and geological knowledge to the problems of exploration and exploitation, for the guidance of the general public and governmental authority rather than of mine executives and directors. The view-point thus reached is likely to differ in many respects from that of men who are much more intimately concerned with the mining problems of a single metal or a single mining field, and for this reason a statement may perhaps supplement those from others whose experience has been markedly different.It may well happen that, at some not distant date in the future, when systematic and comprehensive instruction in economic geology is embodied in the courses- prescribed for mining engineers during their years of training, the author's comments will be quitesuperfluous; but at the present time they appear to him to call for expression.The Need for Training of Mining Men in Economic Geology.Contact over a period of many years with mining men who have had different kinds of training and experience has been convincing that there is a general reluctance to acquire a full rational understanding of the geological factors involved in exploratory and developmental problems. The correction of this attitude is regarded as vital to the industry and it is necessary to insist that the outstanding requirement of the present day is the utilization of all branches of geological, investigation in the field and the laboratoryby men who have had systematic and specialized training in these matters. The science of geology is many-sided, but is, nevertheless, whole and essentially indivisible. No one can afford to disregard any fraction of its content 'or any of its methods of investigation.The greatest advances have been made in the understarnding of the occurrence of mineral deposits by those whose knowledge Qfbasal principles, has been soundest, whose endeavour has been to ascertain all their relationships in space and time, whose attention to detail of all kinds has been keenest, and at the same time, whose capability to distinguish between major and minor features has been most marked.With the passage of the years and the accumulation of data from many lands, it has been possible to build up a great body of information regarding the primary deposition and secondary alteration of mineral occurrences, which is of the utmost value in guiding thesearch for new deposits to take the place of those that become exhausted. This heritage is due not only to the efforts of gifted in...

Jan 1, 1950

By Brad E. Melanson

Because mine haul trucks consume considerable quantities of fuel, they are ideal candidates for the adoption of cleaner and cheaper fuels like natural gas. Impressive fuel cost savings will be realized in regions where liquefied natural gas (LNG) has cost advantage to diesel fuel, while also providing significant reductions of air contaminants and greenhouse gases. High Pressure Direct Injection (HPDI) of natural gas utilizes the diesel cycle combustion process and therefore retains the diesel engine?s high performance and efficiency characteristics. HPDI has been demonstrated in on-road Class 8 trucks since 2001 accumulating almost 10 million kilometres to date. The supply of LNG fuel will be an essential parallel aspect in the introduction of HPDI to mining. LNG can be transported to site as diesel is today, or may be produced on or near mine operations that have access to methane sources or pipelines.

May 1, 2006

By David Estrella, Hector M. Lizama, Jhonny Carrión

"Microcel™ sparging systems were installed on one column of the molybdenum cleaner circuit and one column of the copper first cleaner circuit at Antamina. The Microcel™ system is known to generate finer bubbles than jetting-type spargers, and smaller bubbles have been associated with higher recoveries in flotation. Alternating tests were carried out on the molybdenum column, using either jetting-type spargers or the Microcel™ system. Experimental conditions of gas flow rate, wash water rate, and froth depth were tested. Use of Microcel™ decreased the bubble sizes from 2.6-2.9 mm to 1.5-2.0 mm. In addition, Microcel™ improved both unit molybdenum recovery and unit molybdenum concentrate grade. In the copper first cleaner circuit, side by side tests were carried out that compared the Microcel™ column with a parallel columns fitted with jetting-type spargers. Best results were obtained at manifold pressures of 260-290 kPa, where bubble sizes of 1.6-2.6 mm were observed. In either copper or molybdenum flotation, the Microcel™ system required only 50-60% of the gas flow used by jetting-type spargers.INTRODUCTIONAntamina is a copper-zinc mine located in the Peruvian Andes. Compañía Minera Antamina is owned by BHP Billiton (33.75%), Xstrata (33.75%), Teck Cominco (22.5%), and Mitsubishi (10%). The mine was commissioned in 2001 with a capital investment of US$2.3 billion, and has a nominal 100,000 t/d mill capacity. Mining, milling, flotation, and tailings impoundment take place at the mine site, which sits at an altitude of 4,300 m above sea level. The deposit is a polymetallic skarn ore body with intrusive phases of quartz-monzonite porphyry into Cretaceous aged limestone [Evans et al, 2005]. Ore body thickness is 100 to 150 m and has the shape of a flat-lying crescent. Copper is present mainly as chalcopyrite with a minor bornite component. Zinc is present as sphalerite. Molybdenum is present as molybdenite. Some lead, bismuth, and silver are associated with the sulphides. The deposit is currently classified into six main ore types [Dechert, 2006], grouped into two categories: copper and copper-zinc. The mill produces four concentrate types: copper, molybdenum, zinc, and lead-bismuth. Copper, zinc, and lead-bismuth concentrates are transported by pipeline down to the port of Huarmey. Molybdenum concentrates are bagged and trucked to port."

Jan 1, 2008

By Daniel Mageau

Ground freezing has been used for over 100 years to provide shoring and ground water cutoffs for hundreds of projects worldwide, including drilled shafts, tunnels and cofferdams. Typically, these cases involved difficult soil/water problems where ground freezing was likely the only solution. This paper discusses a recent ground freezing project where a frozen soil wall was used for a more conventional problem. A 4-foot-thick frozen soil wall was used to provide shoring and groundwater cutoff for a 20-foot-deep excavation during construction of a cast-in-place concrete storm water detention vault. The site is located along the northbound on-ramp to I405 from westbound SR522 in Woodinville, Washington. The frozen soil wall was successfully formed in soils consisting of till fill over soft organic silt and loose saturated sand in about 3 weeks. The depth to ground water varied from about 4 to 8 feet over the site. The unfrozen soil inside the frozen soil wall was excavated vertically to the frozen soil boundary. The vertical excavation remained open for approximately 2 months with no dewatering required. On one side, fully-loaded dump trucks and other construction equipment operated within 6 feet of the wall face with zero wall movement. This paper addresses the construction issues related to installation and operation of ground freezing shoring. The overall wall performance of the frozen soil wall as well as basic geotechnical design issues are also discussed.

Jan 1, 1998

By Rozbeh Moghaddam, William D. Lawson, Priyantha W. Jayawickrama, Hoyoung Seo, James G. Surles

"This study provides calibration of resistance factors (?) for design of driven piles to implement Load and Resistance Factor Design (LRFD) for bridge foundations using Texas Cone Penetration (TCP) Test data. The basic research approach was to compile a database of published full-scale load tests including projects from the Texas Department of Transportation’s (TxDOT) historical archive and projects from neighboring state DOTs. Load test results from neighboring states were leveraged by performing new geotechnical borings with TCP tests at the project sites. The final dataset consisted of 30 load tests performed on precast square concrete piles, with pile widths ranging from 356 to 508 mm and penetration depths ranging from 5.2 to 25.5 m, driven in soils. Ultimate capacities for each load test were interpreted based on Davisson, 5%, and 10% settlement criteria. These measured ultimate capacities were compared against predicted capacities estimated from TCP blow count values (NTCP) and design charts following the procedures outlined in TxDOT’s Geotechnical Manual. From the comparisons, statistical parameters of the biases (??= measured capacity/predicted capacity) such as mean and coefficient of variation were obtained. Resistance factors (?) for LRFD were then determined using Monte-Carlo simulations for each ultimate capacity criteria with the target reliability indices of 2.33 and 3.00.INTRODUCTIONThe Texas Department of Transportation (TxDOT) has used the Texas Cone Penetration (TCP) test since its development in the 1940s. The TCP test is an in-situ penetration test to characterize the materials encountered during geotechnical exploration. Texas currently maintains over 53,000 bridges in the National Bridge Inventory (FHWA 2016), and most of these bridges plus other transportation infrastructure in Texas are supported by foundations designed using the TCP test and its associated foundation design method. The Oklahoma DOT adopted the TCP test and foundation design approach in the 1970s, so the foundations for most of the 23,000 bridges in Oklahoma’s inventory were also designed using the TCP method. With this significant body of experience, the TCP method has been viewed as a straightforward, relatively easy-touse foundation design method that consistently yields safe, serviceable, economical, and maintainable foundations. TxDOT’s deep foundation design method is documented in the TxDOT Geotechnical Manual (TxDOT 2012) and currently employs the allowable stress design (ASD) approach. However, the Federal Highway Administration (FHWA) has mandated that the states begin to implement the LRFD method in place of the older ASD approach (Densmore 2000). This paper presents resistance factors at ultimate limit state (ULS) for design of driven piles using the TCP test, resulting from efforts to be in compliance with the FHWA policy."

Jan 1, 2017

By Met M, Orr C. W, Met B. E

As was mentioned in the last paper of this series(l), magnesium was added to lead with the idea that it would act as a de-oxidiser. The magnesium lead alloys give rise to an inter-metallic compound of the composition Mg2Pb(2) and it has some remarkable properties. It is known to disintegrate on standing in the atmosphere and it confers this property also on lead alloys in which it occurs. Magnesium forms a solid'solution with lead, and according to Kurnakow, Pogodin' and Vidusova(S) the limits of solubility are as follow...In conformity with the practice used in preceding series, the limit of concentration used in the present investigation was 0.1 %. Accordingly, it would be expected that all the alloys used would consist of the solid solution and the detrimental Mg2Pb would be absent. Whilst this was the case, it...

Jan 1, 1939

By Tristan Worsey, Nathan Rouse, Kyle Hall

Drilling accuracy is the foundation to any successful blast operation. Even the best blasting practices cannot overcome poor drilling and still obtain desired results. Inaccuracies in boreholes can result in flyrock, increased vibration, uneven floor, and other undesired effects. As depth increases, variation in actual burden and spacing is expected even if collars are located precisely. Problems arise when this deviation reaches a point where it adversely affects the function of the blast design. Not only can unsafe conditions such as insufficient burden at the face develop, but poor fragmentation can compound adverse effects. As with any troubleshooting, problems cannot truly be fixed if they cannot be measured. As a result, significant work has been done in the past on this subject. Currently, there are both cheap and expensive methods used to quantify deviation for a given borehole. However, implementation of these techniques is limited. In general production blasts, little is known about the variance in designed versus true borehole geometry. This is especially true if the blaster does not see telltale signs of drilling deviation. However, losses in blast performance may exist and provide an opportunity to obtain better fragmentation and reduce fines. As drill and blast operations strive for better optimization, greater focus is being placed on drilling accuracy and solutions to this problem. The following paper details the use of several current methods for deviation measurement in order to help prevent compromises of safety and improve overall blast performance.

Jan 1, 2018

By J. C. Bokros, A. S. Schwartz

The irradiation-induced densification of pyrolytic carbon has been shown to take place by a simple first-order rate process. The values of the densification constant, kd, for isotropic carbons are 1.0 x 10-22, 1.4 X 10-22 and 2.8 X 10-22 (nut)-1 at irradiation temperatures of 520o, 670°, and 1000oC, respectively. The apparent activation energy obtained from the temperature dependence of kd for isotropic carbons is about 0.2 ev. Estimates of the maximum stresses that develop in isotropic carbons owing to shrinkage onto an unyielding support show that stresses in excess of 15,000 psi may be avoided during irradiatian at 600" and 1000°C if the initial coating density is kept above 1.5 and 1.9 g per cu cw, respectively. If a carbon coating on an unyielding support is not completely isotropic, stresses may continue to build up at high neutron exposures after densification is complete because of continued anisotropic distortion. Stresses in excess of 15,000 psi from this source may be avoided during irradiation at 1000°C if' the Bacon anisotropy factor is kept below 1.3. A variety of applications of carbon and graphite in nuclear technology has stimulated numerous studies of the effect of neutron irradiation on these materials One of the most interesting problems associated with the use of carbons and graphites in the high fast neutron fluxes of nuclear reactors arises as a consequence of the neutron-induced dimensional changes that occur during irradiation. Energetic neutrons displace car- bon atoms from their lattice positions; and, depending on the temperature, the interstitials and vacancies produced migrate to form clusters, recombine, or are annihilated at dislocations or crystallite boundaries. The competition of various sinks for the point defects results in structure-sensitive bulk-dimensional changes that vary with temperature in a complicated way. This paper deals with the neutron-induced dimensional changes in turbostratic carbons that are being used as coatings on nuclear fuel particles. Details of the structure of these carbons and the variations of their structure with deposition conditions have been reported.'-3 It has been shown in previous work that the neutron-

Jan 1, 1968

By T. L. Johnston

The Dobbins property, about 4-1/2 miles northeast of Cartersville, Ga., was fist operated in 1866, it is the oldest manganese mine in Georgia and one of the oldest minus in the United States still producing manganese ore. Changes in ownership, lessees, and operators and lack of records prevent the compiling of statistics regarding total production of ore from the property.

Jan 1, 1942

By T. L. Johnston

The Dobbins property about 4-1/2 miles northeast of Cartersville, Ga., was first operated in 1866. It is the oldest manganese mine in Georgia and one of the oldest mines in the United States still producing manganese ore. Changes in ownership lessees and operators and lack of records prevent the compiling of statistics regarding total production of ore from the property

Jan 1, 1942