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By C. A. Geffen

This report, sponsored by the U. S. Bureau of Mines, presents the results of an examination of the safety of the impactor shaft sinking system in comparison to conventional shaft sinking technology. Detailed study of the impactor system was also performed to identify and recommend design changes for optimum safety conditions. A comparison of the impactor machine and its support systems with conventional shaft sinking was made on the basis of relative risk levels. Risk incorporates measures of both the frequency and the potential consequence of accidents. A safety evaluation of the com¬ponent operations of the impactor shaft sinking system was performed using a Failure Modes and Effects Analysis (FMEA) methodology. The results of this analysis show generally that the impactor shaft sinking system is safer than conventional shaft sinking. The potential risk of conventional shaft sinking operations could be reduced by an average of over 35 percent with use of the impactor shaft sinking system. Design change recommendations to further improve the safety of the impactor system include a revised fire suppression system, improved access to and from the operator cabs, reliable noise attenuation measures and improved communication systems. An operational safety manual was also developed for the impactor shaft sinking system.

Jan 1, 1982

By A. Taylor, E. Thorn Corthay, J. Farrell, L. A. Westfall, S. Borchardt

Mining and metallurgical industries need to minimize their greenhouse gas (GHG) emissions; Hatch specializes in conducting mining and metallurgical energy management assessments and optimizing productivity. Projects executed have demonstrated that there is a wealth of energy management, waste reduction, and process efficiency improvements that require no or low capital investment. Typical energy cost savings are on the order of 5% to 12%, with similar reductions in GHG emissions. Hatch generates Marginal Abatement Cost Curves to optimize the implementation pathway, maximizing carbon abatement and minimizing cost. The findings of a practical case study from Cameco are presented.

Jan 1, 2010

By Manqiu Xu, Songtao Yang, Zongfu Dai, Robert Pelton

"Hydrophobic polystyrene nanoparticle suspensions were evaluated as potential flotation collectors for pentlandite. Experiments involving both clean model mineral suspensions and complex ultramafic nickel ores confirmed that conventional water-soluble molecular flotation collectors such as xanthate could be partially or completely replaced by hydrophobic nanoparticle flotation collectors. The ability of nanoparticles to induce flotation was demonstrated by floating hydrophilic, negatively charged glass beads with cationic polystyrene nanoparticle collectors. Electrostatic attraction promoted the spontaneous deposition of the nanoparticles on the glass surfaces raising the effective contact angle sufficiently high to promote the adhesion of beads to air bubbles. As little as 10% coverage of the bead surfaces with our most effective nanoparticles could promote high flotation efficiencies, whereas conventional small molecular flotation collector requires ~ 20% or higher coverage for a good recovery. Surface functionalized nanoparticles enhanced the ability for nanoparticle collectors to selectively deposit onto surfaces of the desired mineral particles in the presence of gangue. For example, poly (styrene-co-vinylimidazole) nanoparticles were designed to selectively deposit onto nickel mineral (pentlandite) in the presence of Mg/Si slime. Flotation tests of ultramafic nickel ores at Vale with these nanoparticle collectors have shown improvements in both pentlandite recovery and selectivity. On-going work includes attempts to identify specific applications where nanoparticle flotation collectors might be cost effective.INTRODUCTION Most mineral processing operations include multiple stages of froth flotation to concentrate and isolate the desired product. Before flotation, chemical collectors are routinely added to ground ore slurries, selectively binding to mineral-rich particles, increasing their hydrophobicity thus promoting selective flotation. (Fuerstenau, Jameson, & Yoon, 2007) Conventional collectors are surfactants with a short hydrocarbon tail and a head group, such as xanthate. A typical conventional collector is potassium amyl xanthate (PAX), which is a small molecule with an extended molecular length of about 1 nm. Critical characteristics of a good collector include the ability to selectively adsorb onto desired mineral surfaces and to lower the water/mineral surface energy. Despite the extensive role of flotation in mineral processing, some ores are difficult to process by flotation. For example, ultramafic nickel sulfide ore containing both valuable pentlandite and large quantities of unwanted Mg/Si slime [primarily serpentine, (MgFe)3Si2O5(OH)4] responds poorly to flotation. (Mani, Xu, Quinn, & Stratton-Crawley, 1997) Fibrous hydrophilic Mg/Si slime usually masks the surface of pentlandite (known as “slime coating”) due to electrostatic interaction (Edwards, Kipkie, & Agar, 1980) and dramatically depresses pentlandite flotation. Consequently, new approaches are required for processing these difficult ores."

Jan 1, 2012

By R. C. Hickman

Preliminary evidence indicated that the Chattanooga Shale might constitute a potential vast low-grade source of uranium. Investigation by core drilling indicated that while the Chattanooga Shale may constitute a resource for the future, the very low (0.006 percent) average uranium content is not economic when compared with the relatively higher grade western ores. A total of approximately 12,000 feet of test drilling was done in 72 drillholes, and large samples were mined for extractive and metallurgical testing. An experimental mine site was selected on the basis of the drilling project.

Jan 1, 1967

The kinetic and practical aspects of the extraction of copper from copper-rich solutions by cementation on iron was investigated. Tests were made on the effect of stirring speed, cupric sulphate concentration, acid concentration, temperature, and ferric sulphate concentration on the reaction rate and excess iron consumption.Most kinetic investigations were conducted under a nitrogen atmosphere to prevent any oxidation of the iron or copper metals. The stirring mechanism for all tests incorporated the use of a rotating impeller above a static disc in the solution. The activation energy for cementation on the steel disc at high stirring speed was 8·6 kcal/mole, indicating a predominant chemical control.Increasing the pH first decreased, then above pH 3, increased the reaction rate. Additions of sodium sulphate also significantly increased the reaction rate.The use of high temperature and high pH under an inert atmosphere has been suggested for increasing the reaction rate and producing a high purity sponge copper product.

Jan 1, 1972

By Eduardo Lozano, Vilem Petr

This paper provides an overview of a new method for avalanche control using a high explosive charge placed at the avalanche runout zone: the case charge technique. This new avalanche control technique is well-suited to mountain roads presenting several advantages over the existing methods: minimum deployment time, low cost, reduced probability of misfires, and decreased operation time in the avalanche danger zone. The research work presented in this paper was conducted via large scale laboratory experiments where the detonation velocity and the blast physical properties were measured. During the charge design, several parameters were controlled: charge mass, diameter, geometry, density, and external confinement. In addition, the effective range of case charges was increased by the use of the Mach reflection for certain topographical situations. Finally, field test results collected by the Colorado Department of Transportation (CDOT) during the 2017 winter season are presented. The CDOT avalanche control crews have adopted the new case charge as the preferred technique in numerous avalanche locations along the Rocky Mountains roads.

Jan 1, 2018

By Víctor De la Cruz

Dado que la mina Rosaura (Lima) se dedica a la explotación de minerales polimetálicos como el zinc, plomo, cobre y plata, la caracterización geomecánica de su estructura, morfología y reservas demostró una tendencia hacia los métodos masivos -en tanto presenta ventajas técnico-económicas comparativas frente a otros posibles métodos como el corte y relleno y conjunto de cuadros. Por ello, el presente texto describe el método de “Hundimiento por Subniveles” (Sub Level Caving – SLC), como el más indicado. El SLC se basa en la utilización del flujo gravitacional del mineral fragmentado a través de la perforación, voladura, y el hundimiento de la roca estéril principalmente de la caja techo. El diseño del elipsoide de extracción determinará la ubicación de los Sub niveles y Drawpoints, los cuales serán críticos para hacer rentable el minado, de forma que los beneficios actuales del método indican niveles altos de Seguridad, recuperación alta de mineral, bajos costos y mejora constante de la productividad.

Sep 9, 2007

By Christian Neumann, Josef Arnold, Albin Reinhart

The Channel Tunnel Rail Link (CTRL) is the most significant railway infrastructure development project in the United Kingdom since the construction of the Channel Tunnel between France and England. The key element of this project is the 2-mile-long(3.2-km) North Downs Tunnel, which will be the largest and deepest twin-track railway tunnel ever constructed in the United Kingdom. This paper describes the contractual agreement, the design and construction (excavation and lining) of a twin-track rail tunnel with a 166-m 2 face excavated through chalk using the New Austrian Tunnelling Method (NATM). The importance of collaborating with a tunnel contractor/designer who not only is expert in the New Austrian Tunnelling Method, but who was also responsible for the design and installation of the primary lining, will be highlighted in this paper. This paper will also deal with the benefits of partnering in tunnel design and construction, as well as the resultant added values of mechanizing conventional tunnelling methods (Value Engineering).

Jan 1, 2001

By Dennis W. Boehm

The building boom of the late 1970's and early 1980's has all but used up most of the better sites across the more populated metropolitan areas of the United States. This means that current buildings and other types of structures are being founded on more marginal sites. The use of marginal sites has placed ever-increasing quality control on the installation of the deep foundation systems utilized for these sites. Several remedial techniques are available for the repair of the deep foundation systems. These include minipiles, compaction grouting and jet grouting. Eight case histories are cited where these methods have been utilized to repair deep foundations.

Jan 1, 1999

By Juan Carlos Lozada

YURA S.A. es una empresa industrial cuyo principal actividad es la fabricación y comercialización de Cementos Portland y adicionados, conglomerados de albañilería y concretos. Asimismo proyecta la construcción de una nueva línea de producción de Clinker. En ese sentido, el presente texto señala el sistema de gestión que se utilizó para mejorar las prácticas sugeridas por el PMI (Project Management Institute) en la Guía del PMBOK, y cómo se aplicaron las diferentes herramientas a las situaciones particulares del mismo.

Sep 12, 2011

By T van der Meer, A Salokannel, M Martikainen, L M. Nevatalo, J McCulloch

Water use and wastewater management is becoming a focus for many industries around Australia and the rest of the world. Good quality water is increasingly being recognised as a precious resource, and regulations on the bulk storage and discharge of waste streams is becoming more stringent in order to protect the environment, existing water reserves and the communities that use these resources. Components such as heavy metals, arsenic, cyanide, and sulfate from acid mine drainage are some that occur at mining and metallurgical processing sites. Removal of such components can allow safe re-use of these streams, reducing the new water requirements of the process, or else allowing acceptable discharge to the environment. Re-use or discharge of treated water eliminates or reduces the risk associated with storage of large volumes of contaminated water on site.Technologies where a contaminant is selectively precipitated and removed as a sludge are used for many of these treatments. Selection of the best treatment option for wastewater must depend on what is suitable to each site, and consider not only the nature of the contaminant, but also other aspects, including the location and situation of the site, local regulations, cost of reagents, the sensitivity of the local environment and waste sludge disposal options. To outline how an effective and economical solution can be designed and delivered, this paper will present a case study for the removal of arsenic from a site wastewater, from assessment of the problem, selection of suitable technology, design and implementation, to the benefits delivered to the site.CITATION:Salokannel, A, Nevatalo, L M, Martikainen, M, van der Meer, T and McCulloch, J, 2013. Technology selection for removal of contaminants from an industrial wastewater, in Proceedings MetPlant 2013 , pp 531-538 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

Perhaps one of the most important conferences or symposia which our Institute has conducted, was the joint Aus. LM.M./AJ.M.E. meeting held in Canberra in May 1978, with the theme International Resource Management (Woodcock, 1978).We were privileged to witness active participation in the meeting by outstanding personalities from the mining and metallurgical industries of Australia and New Zealand, the United States of America, Canada and the United Kingdom and to hear addresses on subjects of international significance to the mining and metallurgical industries.Our Institute is one concerned with professionalism.The principal objects of The Institute as described by our founders include, "promoting the arts and sciences connected with the economical production of the useful minerals and metals, and the welfare of those in the industries, by meetings for social intercourse, and the reading and discussion of professional papers, and to circulate by means of publications amongst its members and associates, the information thus obtained".Sir Maurice Mawby (1968) said in his Presidential Address to the Institite, "the most important aspect of these objects was the promotion of the arts and sciences of the mining industry".Why is it then, that a large proportion of the papers given at the meeting in Canberra dealt with world wide social aspects of the mining and metallurgical industries, rather than the technology, the arts and sciences of mining and metallurgy as principal factors in international resource management?The answer is quite simple of course, and that is that the social and political factors are the principal factors which create the demand for basic raw materials and in the long term determine the costs and prices of the commodities which our professional abilities are drawn upon to produce.

Jan 1, 1979

By A Teen

An open cast mine on the West Coast of the South Island of New Zealand proposes to remove up to 30 m of overburden to access an ore body neighbouring National Reserve land. Part of the conditions of the mining permit is that no material above natural discharge levels may be released over the Mining Lease boundary onto the adjacent land. In order to meet this requirement, the client has contracted the design and installation of over 2.6 km of high energy dynamic rockfall control barriers. This paper describes how the rockfall hazards were assessed and the rockfall barriers dimensioned. The design involved 2D modelling of over 3000 simulations.   Modelling parameters were calibrated during field trials at a purpose built section of barrier. The resultant energies ranged from 500 to 3000 kJ. The construction phase of the project involved the drilling, anchoring, and installation of certified barriers up to 7 m high in a remote and inhospitable climate with limited machinery access. By exploring best practice in this specialized field of engineering, a novel rockfall hazard mitigation solution was identified.

Jan 1, 2007

By Antti J. Perala, Teemu J. Yli-Kovero

"Efficient use of land is constantly requiring more underground construction. Minimized execution time and disturbance to surroundings and nearby structures are essential benefits for all construction techniques. To meet the demands of a modern construction project, suppliers have to be able to provide high-quality and tailor-made products just on time. RD pile wall is a retaining wall based on drilled steel pipe piles which are connected to each other with special interlocking profiles. RD pile wall is a solution which enables penetration of overburden soil, dense fill layers including stones and boulders, and embedding into the bedrock in one single operation. Several test installations and laboratory tests have been made to develop the system and to test and improve the water tightness of the wall. Beside these tests, RD pile wall has also proven its reliability in almost 70 projects. Largest project so far has been Pasila Tripla project in Helsinki, Finland. A permanent retaining wall with surface area of 18,000 m2 (193,750 ft2), excavation depth of 21 m (68 ft) and over 17 m (56 ft) of water pressure was made with 711 mm (28”) and 406.4 mm (16”) pile sizes. Piles were delivered to site in one piece with lengths up to 33.5 m (110 ft).INTRODUCTIONExcavations in cramped city centers and in between of existing buildings and other structures are facing more and more challenges. Installation of sheet pile walls is often problematic or even impossible due to obstacles in ground from old structures and due to demand to extend the excavations to even deeper and harder soil layers. Also installations of secant pile walls are facing difficulties due to cramped construction sites and constantly tightening execution times.On the other hand, an efficient and reliable piling technique suitable for the demanding soil conditions described above, percussion drilling, has been developed since the 1960’s, and especially from the mid- 1990’s, when the concentric drilling method with the ring bit and pilot was introduced. A new retaining wall application, the RD pile wall, was developed by combining that drilling method with the widely used retaining wall solution based on steel pipe piles and welded interlocks (a pipe pile wall normally installed with vibratory or impact hammers).PRINCIPLE AND MAIN BENEFITS OF THE METHODRD pile walls can be used in all soil conditions. Most beneficial the system is in extremely demanding soil conditions where the installation of traditional retaining walls is challenging or even impossible. The RD pile wall is a combination of drilled steel pipe piles and interlocking sections as shown in Fig. 1.Individual RD piles are connected to each other with interlocks welded to the piles on the automated welding line at the workshop. The matching dimensions of the drilling system and interlocking sections allow the installation of RD piles through stones and boulders and even into the bedrock, if necessary, in a single operation. Installation is done by a down-the-hole (DTH) hammer using the centric drilling system and oversized ring bits or a drilling system consisting of a pilot bit and reamer wings shown in Fig. 2."

Jan 1, 2017

By D. Randolph Berry

The United States Bureau of Mines (USBM) awarded a contract to Foster-Miller, Inc. to develop guidelines for the storage and use of Self-Contained Self-Rescuers (SCSRs) in underground non-coal mines. An SCSR is a device capable of supplying, in an emergency, one hour of self-contained oxygen (no breathing of mine air). The information and recommendations in this report were developed primarily from three sources: discussions with mine representatives (including management, labor, and government), site visits in underground mines I and a detailed analysis of every reported non-coal accident which produced d hazardous atmosphere during the 5-year period 1976-1980 -plus ten other major incidents from prior years. Volume IV has three major sections: Recommendations and Discussion (Section 2), Analysis of Mine Accidents (Appendix A), and a Summary of Discussions with Mine Representatives (Appendix B).

Jan 1, 1983

By James J. Neate

The augered cast-in-place pile system came into use in the late 1940's where various techniques were tried using pressure grouting methods. In the early development stages some piles were installed using the preplaced aggregate concrete system. As development continued it became more apparent that placement of coarse aggregate was more costly than making a pile out of a cement and sand mixture only. Various techniques were tried consisting of pumping structural grout into an open hole through a pipe left in the bottom of the hole, drilling or driving a pipe in close proximity to the tip elevation of the auger or in working a pipe down adjacent to the auger fluting. For these techniques the pipe was usually withdrawn after grout appeared at the surface. In 1951 a patent was applied for by Raymond Patterson describing the above techniques along with a technique for placement of grout using a hollow stem auger and a removable plug or lead bit at the tip of the auger. The plug or lead bit was removed by grout pressure and this would be an expendable item for each pile placed. The patent was granted in 1956 and patent rights were assigned to Intrusion-Prepakt, Inc. Shortly thereafter other contractors were granted licenses to utilize the system. Patent coverage expired in 1973 and this method now is in the public domain. Today the method is in wide use throughout the world and is particularly well accepted in Japan and England.

Jan 1, 1988

By Wade A. Narin, James K. Mitchell

Hydroblasting is considered a distinct soil improvement technique from explosive compaction, though the blast designs for the two techniques are similar. Hydroblasting is a three step process developed for densifying unsaturated, collapsible soils, especially loess. The required steps are: prewetting the soil to an adequate saturation, placing and detonating the explosive charges, and consolidating the soil (squeezing the water out of the pore spaces between the soil particles under gravity) to a denser state.

Jan 1, 1995

By Russel Delmar

Construction of Ontario Power Generation?s 12.8-m diameter, 10.4-km long water diversion tunnel in Niagara Falls, Ontario, is underway. The tunnel is being excavated by means of a 14.44-m diameter open gripper Tunnel Boring Machine. The tunnel lining is constructed as a two-pass system with the initial lining consisting of rock bolts, mesh, steel channels or ribs, and shotcrete, and the final lining consisting of pre-stressed cast-in-place concrete with a waterproof membrane. This paper describes salient design and construction aspects as follows: ? Regional and Site Geology ? Tunnel Layout and Design ? TBM Tunnelling and Cast-in-place Concrete Lining Construction

Jan 1, 2008

By J Wallis

The stability of a raise bore is often assessed using the rock mass classification system published by McCracken and Stacey as a modification of the Q system. Often the assessment is done using a spreadsheet to manipulate geotechnical log(s) of boreholes. This paper discusses the inherent difficulties with this approach. Recent work by others to provide guidelines to the classification system is discussed. A recent example of the design and raise bore performance at Macraes Gold Mine, New Zealand is presented. A key issue is that a visual assessment of the drill core and/or core photographs is necessary to æground-truthÆ the classification.

Jan 1, 2008

By Jim Rix, Ken Been, Nihal Bohra, Anthony Rice, Juan Lopez

"A temporary bridge, supported on steel pipe piles, was built to expedite the construction of a breakwater structure off the western coast of Peru. The bridge provided access for dump trucks to the breakwater across a 342 m (1122 ft.) wide navigation channel from a liquefied natural gas (LNG) loading facility, at the end of a 1.3 km (0.82 miles) long permanent trestle, in 15 m (50 ft.) water depth. After the completion of the breakwater, the temporary bridge was removed, and the piles were extracted approximately one year after the initial driving. The bridge deck was typically supported on pairs of 914.4 mm (3 ft.) diameter, 18 mm (0.708 inch) wall steel pipe piles spaced at 7.5 m (24.6 ft.) across the bridge width and 18 m (60 ft.) along the bridge length. In an attempt to reduce the driven pile embedment, an inner closure plate was installed at 2.7 to 7 m (9 to 23 ft.) from the pile toe to force closed-end behavior. The piles were designed to carry 3400 kN (383 tons) axial compression load, and a minimum of 8 m (26 ft.) embedment was specified to provide sufficient resistance to the lateral loads.The subsurface conditions consisted of cemented conglomerate of sand, gravel, pebbles and some boulders, locally known as the Cañete Formation. The driven pile embedment varied widely, between 8 to 24 m (26 to 79 ft.). A significant portion of each pile was above the seabed, passing through seawater and up to the bridge deck, and was therefore unsupported. The extraction of the piles was challenging due to the subsurface conditions, presence of significant water column, pile weight, and the inner closure plate. Several different approaches were attempted before the piles could be successfully extracted. This paper summarizes the difficulties encountered and observations made during the driving and extraction of these piles."

Jan 1, 2017