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By Hasan Nizamoğlu, Z. Abidin Sarı, Aslıhan Demiraslan, M. Deniz Turan, Tolga Depci

In this study, recovery of copper from solid material (obtained by leaching of chalcopyrite with oxalic acid in the presence of hydrogen peroxide) with a copper oxalate structure was carried out selectively using HCl. The chemical composition of the solid was as 29.3%, 9.7%, and 13.3% for Cu, Fe, and S, respectively. Selective recovery of copper by degrading the copper oxalate structure with a low-solubility product (Ksp = 4.43 × 10−10) was performed by conventional leaching in the presence of HCl. The optimum leaching conditions were determined as 5 M of HCl concentration, 318 K of leaching temperature, 120 min of leaching time, 25 ml/g of liquid–solid ratio and 400 rpm of stirring speed. Under these conditions, approximately 77% of copper and 3% of iron were taken into the solution. According to the characterization of the leach residue that was obtained, the oxalate structure was degraded. Moreover, the results of XRD analysis showed that the sulfur (S) and cubanite (CuFe2S3) phases were mostly observed in leaching residues, and this was supported by the SEM-EDX data. Based on the results, it may be stated that selective copper extraction can be obtained from a chalcopyrite concentrate by a two-step leaching method using a conventional hydrometallurgical technique.

By Arthur D. Silber

The economic success and growth of any metropolitan region depends on mobility. Today, mobility between New Jersey and New York is threatened by a transportation system that cannot meet 21st century travel demands. The transportation bottleneck created by the Hudson River threatens the viability of one of the world?s great centers of commerce and culture. Fortunately, there is a solution: The Access to the Region?s Core Mass Transit Tunnel. The US$8.7-billion Mass Tran-sit Tunnel?s (MTT) new two-track line will double commuter rail capacity under the Hudson and create a new, state-of-the-art cavern station in Midtown Manhattan, with wide platforms, high-speed escalators and other features to improve riders? travel experience. The capacity and other benefits of the MTT project will launch a new era of prosperity for the region, just as the Pennsylvania Railroad did almost 100 years ago when it built the existing two, single-track rail tunnels that now form the sole commuter rail link between New Jersey and New York. The existing tunnels run from North Bergen, NJ, under the Hudson River to Pennsylvania Station at 33rd Street in Manhattan. Construction on the MTT, the largest public works project in the United States, is scheduled to start this year and continue through 2017. The MTT is ready to go to construction thanks to a major commitment of financial, engineering, project management and other resources from NJ TRAN-SIT, New Jersey?s statewide mass transit agency, and the Port Authority of New York and New Jersey, a bistate agency that operates the Holland and Lincoln tunnels, the George Washington Bridge and other major transportation facilities in New York and New Jersey. The project is also strongly supported by the state governments of New York and New Jersey, as well as that of New York City. The MTT is New Jersey Governor Jon Corzine?s number one transportation priority.

Jan 1, 2009

By Chaoxun Zhao, Daniel Tao, Craig Blue, Narendra B. Dahotre, Rick Honaker, Bhupendra K. Parekh, Hongyang Han

Equipment wear and corrosion have significant adverse impacts on the operating cost and efficiency of mineral processing plants. In this project advanced surface enhancement technologies are being investigated to decrease the wear and corrosion rate of metal surface. Enhanced metal surfaces are achieved through surface conversion, enrichment, and coating by use of advanced High-Density Infrared (HDI) and other technologies. Studies have been done to determine the effects of process parameters on surface properties and identify optimum conditions. The microstructure of the enhanced metal surfaces was characterized by SEM, EDS, and microindentation. Laboratory wear testing was carried out to investigate the wear performance and the viable coating candidate was determined.

Jan 1, 2005

Equipment-washing facilities at Freeport-McMo-Ran?s Sierrita Mine in Arizona produce a mixture of oil and water that was difficult to dispose of easily or cheaply. However, after some changes in the facility, waste oil is now used as part of the mining process. Freeport-McMoRan Copper & Gold Inc., head-quartered in Phoenix, AZ, operates copper, gold and molybdenum mines. It is the world?s largest producer of molybdenum. Heavy equipment used at the mine is hosed off periodically in the wash bay. The dirty water and oil mixture drains into the sump next to the bay. Oil was manually collected for disposal. This was a tedious and dirty process Mine managers sought a more efficient method of removing the oil. Instead of spending the time and effort skimming the tank with vacuums or sorbents, they enlisted the help of Abanaki Corp., manufacturer of the Model 4 Oil Grabber. Engineers designed the sump to utilize prevailing winds to blow the oil to one corner. This was the ideal place for the Abanaki skimmer. The skimmer removes the oil and discharges it into a plastic storage container. ?This reduces the time needed to keep the area clean, and the staff can focus on cleaning the equipment rather than worrying about the oil,? according to Jay Salerno, construction manager at the Sierrita Mine. Salerno is considering adding an optional oil concentrator to the skimmer to make the process even more efficient. The concentrator would remove any water picked up by the belt and return it to the sump, leaving nearly pure oil for disposal. Because the mine is located in the Sonoran desert, most of the water evaporates in the hot, dry air and is not reused.

Jan 1, 2009

By Nick Salisbury, Alan Howard, Scott Tunison

INTRODUCTION Geotechnical investigations for tunneling projects typically use vertical test borings and, to a lesser extent, angled borings. Horizontal drilling applications were often limited to specialty testing programs and to perform probe drilling from a tunnel boring machine (TBM) as part of production tunneling. The former often involved cumbersome setups with skid rigs and cribbing in a pilot tunnel or shaft. The latter usually was limited to generic probing for rock quality and ground water conditions with no sampling. Neither yielded continuous core at production rates suitable for design and construction planning. Conventional vertical investigations still make sense in many instances, particularly for tunnels planned beneath urban settings where truck access is convenient and where the tunnel horizon is not readily accessible via a portal or shaft. However, equipment is presently available to conduct horizontal geotechnicall investigations at reasonable production rates and cost. Advantages include continuously sampling the tunneling horizon and minimizing “access drilling” to get the zone of interest at the underground construction horizon. Horizontal boring lengths of up to approximately 800 m are considered feasible and those in the range of 150 to300 m are now routine. These capabilities make horizontal borings an attractive option to consider when looking at deep tunnels beneath ridges, especially where access is limited. Fewer drilling staging sites can also mean reduced environmental impacts when investigating tunnels proposed beneath sensitive lands such as public wilderness areas. Investment in early construction packages to develop portals for investigation access and, possibly in excavating test shafts for the same purpose should even be considered. Potential benefits in the form of achieving improved overall project costs using horizontal borings exist because of the significant additional data collected in the tunnel horizon. For this reason they should be considered during the routine cost-benefit analyses generally conducted for planning geotechnical investigations for tunneling. The authors also believe that collection of such data will reduce Geotechnical Baseline Report (GBR) conservatism and lead to lower potential for

Jan 1, 2005

On Nov 1, 2007 House Resolution 2262 ? The Hardrock Mining and Reclamation Act of 2007 ? was passed by the U.S. House by a vote of 244-166. HR-2262, among other things, would impose a 4-per-cent royalty on existing mines with commercial production and an 8-percent gross royalty on all new claims. Not surprisingly, this possible new law was one of the hottest topics of discussion at the Northwest Mining Association?s conference that this year returned to Spokane, WA for its 113th annual meeting on Dec. 3-7. More than 1,800 delegates attended the conference that was held under the banner theme of ?Mining ?. For today and tomorrow.? Northwest Mining Association executive director Laura Skaer was one of many speakers during the three-day conference to respond to the threat to the industry posed by HR-2262 with a presentation titled ?Potential changes to the 1872 Mining Law.? In the presentation that she first unveiled at the Alaska Miners Association?s convention and trade show on Nov. 8, Skaer laid out a comprehensive list of problems with HR-2262. In addition to the association?s obvious concerns about the proposed royalty, Skaer noted that the bill includes a mine veto provision that would allow the Secretary of the Interior the authority to deny an operations permit to a project if the secretary determines that the operation would cause undue degradation to public lands and resources. Potential massive withdrawals from mineral entry are also included in HR-2262. Among the lands that could be off limits to miners under HR-2262 are wilderness study areas, areas of environmental concern and 23.6 hm2 (58.5 million acres) identified as Roadless Rule. States, political subdivisions and Indian Tribes would also have more authority to withdraw lands, she said. To combat the proposed changes, Skaer made 10 trips to Washington D.C. on behalf of NWMA members in 2007. In her presentation at the annual meeting, she also objected to provisions that include no life-of-mine permits and uncertain permit renewals and new and duplicative environmental standards that she said are vague, ambiguous and inconsistent with current federal and state environmental laws. Debra W. Struhsacker, an environmental permitting and government relations consultant, also spoke on the issue of HR-2262 with a presentation titled ?The House mining law bill ? Rip van Winkle is back ? and he?s meaner than ever.?

Jan 1, 2008

By Timothy P. Smirnoff

Sustaining the region?s mobility needs, achieving projected economic growth, and maintain Midtown Manhattan as a center of regional, national and global importance has led to continued investment in commuter rail and transit infrastructure in New York City and resulted in design and construction of large underground caverns. The current plans for stations in Manhattan include New York Penn Station Expansion (NYPSE) caverns for Trans Hudson Express (THE) Tunnel Project for New Jersey Transit (NJ Transit) and the Port Authority of New York and New Jersey (PANYNJ), Metropolitan Transportation Authority Capital Construction Long Island Railroad (MTACC/LIRR) twin caverns for East Side Access (ESA) Project, and station caverns of the No. 7 Line Subway Extension Project and Second Avenue Subway Project for Metropolitan Transportation Authority Capital Construction/New York City Transit (MTACC/NYCT). This paper provides a general overview of these large caverns now in design or construction in Manhattan, the area?s geologic setting, the geotechnical factors considered and approaches commonly applied for cavern design.

By R. Patterson

Tracer gases have been utilized successfully in a variety of industries, each with specific releasing and sampling methods. The various attributes of tracer gases are dependent on the industry the tracers are utilized in. Tracers must be chemically and thermally stable, safe, odorless, detectable at low concentrations, have a low background concentration, and should not be naturally occurring in the environment if they are utilized in underground mining applications (Thimons et al., 1974). In addition, the tracer gas should be inexpensive, non-corrosive, non-toxic, easily transportable, readily attainable, and non-radioactive (Kennedy et al., 1987). Sulfur hexafluoride (SF6) met many of these above requirements and therefore was introduced as an ideal tracer gas to use in mining industry in the early 1970?s (Thimons et al., 1974). Due to the nature of underground mining including complicated geometry, irregular flows, turbulent flows, obstructed airways, and leakages it is difficult to use conventional anemometer and smoke tube techniques to accurately measure the effectiveness of ventilation controls (Thimons et al., 1974; Klinowski and Kennedy, 1991). There have been several applications of SF6 as a tracer gas in underground metal/non-metal and coal mines. Thimons et al. conducted early testing of SF6 in an underground limestone mine and determined that it is an effective technique for evaluating auxiliary fans, estimating volumetric flow rates in large areas, and measuring low flow velocities. A rapid face ventilation measurement method (FVM) utilizing SF6 was developed by the Bureau of Mines to make face measurements in underground coal mines (Timko and Thimons, 1982). When measuring the effectiveness of jet fans in dead headings SF6 was proven more effective than smoke tubes (Timko and Thimons, 1982). Experiments related to determining methane liberation in the gob were also conducted by injecting SF6 into a borehole (Timko and Thimons, 1982). Also, in an emergency situation where the gob had to be sealed due to a fire, SF6 was released to determine the effectiveness of the seals (Timko and Thimons, 1982).

Jan 1, 2011

Steady increases in longwall production have required operators to apply greater quantities of ventilating air in an effort to control and dilute respirable dust. Significant increases in shearer speeds necessitate that longwall supports also be advanced at a faster rate. Both of these factors may contribute to overall respirable dust levels on the longwall face because as supports are lowered and advanced, broken material falling from the top of the canopy is entrained directly into the air stream. To address this issue, the Pittsburgh Research Laboratory collected respirable dust samples from four longwall faces to characterize shield-generated dust. This paper investigates the influence of air velocity and shield advance rates on respirable dust levels. Also discussed are engineering controls currently used to reduce shield dust and alternative controls being investigated by the National Institute for Occupational Safety and Health (NIOSH).

Jan 1, 2009

The theme of the 2012 North American Tunneling conference (NAT) was ?Tunneling: Driving Value.? This theme best reflects where the tunneling and underground construction industry is to-day. Major advances that have been made in technologies have provided tremendous improvements in productivity, which, in turn, have allowed the industry to deliver more cost-effective and less disruptive solutions to the nation?s infrastructure needs. Despite a weak economy, domestically and globally, cities and states continue to spend billions on infrastructure improvements. For the underground construction industry, that means more transportation and water, wastewater, storm water projects and other underground structures. And, for each project completed, underground construction and tunneling technology grows. The NAT conference, put on by the Underground Construction Association (UCA) of SME, provides an outlet for technology transfers among professionals. This year?s conference, held in Indianapolis, IN June 24-27, attracted 918 attendees, up from 803 at the last NAT in 2010. The accompanying exhibit also featured 116 exhibitors occupying 140 booths. That was up from 108 booths in 2010. So, the meeting continues to grow as underground construction professionals throughout the world seek to learn from their peers.

Jan 1, 2012

By David Hake, David Salisbury

The Drainage Services Department (DSD) of the Hong Kong SAR Government commissioned the design and construction of the West Kowloon Drainage Improvement, Stage 2, Phase 2, Kai Tak Transfer Scheme (KTTS) project in 2000 to relieve potential flooding in Mong Kok caused by the insufficient capacity of the existing storm water drainage system. The KTTS involves construction of a 1.5km,4.4m drainage tunnel and a 450m long box culvert, running from Waterloo Road near Hereford Road to the existing Kai Tak Nullah in San Po Kong. This paper describes the design and construction of; the bored tunnel through both hard rock and soft ground using a slurry Tunnel Boring Machine (TBM), six associated access shafts, a connection structure at Waterloo Road and the box culvert connecting the bored tunnel to the outfall at Kai Tak nullah. Details will be provided on the contractor’s alternative designs adopted during the contract including the use of fibre reinforced shotcrete as one-pass temporary and permanent support for three of the shafts and modifications to the Engineer’s design for the box culvert structure.

Jan 1, 2005

By G. F. Jenkins, P. S. Hobden

Toronto as a geographical area provides an exceptionally wide variety of subsoil stratiphication. Tunneling consequently required a very wide range of adaptabilities to meet its changing conditions. This discussion will provide a summary of work performed in both earth and rock formation using three of our recent works to describe a Contractor's experience. The general subsoil stratigraphy is known to consist of deposits laid down during the Illionian Glaciation followed by the Samgamon Interglacial Stage and finally the Wisconsin Glaciation. All these deposits are underlain by shale bedrock of the Dundas formation. As a whole the Dundas formation is predominantly a greyish blue, thinly bedded shale. The engineering characteristics of the shale vary considerably, however, between a blue clay (argillaceous) shale and a much lighter (in colour) silty and sometimes sandy (arenaceous) shale, and occasional limestone layers. The Illionian deposits are usually found to be layers of pebbly clay till and an overlaying layer of contorted varved-clay. These glacial deposits can be overlain by a thick layer of sandy silt to silty sand which is identified as the Samgamon Interglacial sediments. Because of the action of erosion the Wisconsin till sheets, many times separated by interstadial sands, can vary greatly in their number of layers from zero to three or more.

Jan 1, 1997

By T. C. Eisele

The use of column flotation was considered for the ?reverse flotation? of iron ore, where the gangue (quartz) was recovered in the froth product. This use of the froth for carrying the gangue mineral rather than carrying the valuable concentrate significantly changes the operational requirements of the column. The objective of this work was to determine which of several column flotation technologies would be most suitable for this type of flotation operation. Studies were carried out using both the Jameson column and the Deister column. Comparative results are presented that show the capabilities of both column types in this application relative to conventional Wemco flotation cells. Columns were demonstrated to have grade-recovery performance superior to what could be achieved with conventional cells. Two-stage flotation with the columns could produce a concentrate that was up to 70.2% Fe at 87.5% iron recovery, compared to 70.4% Fe at only 77.7% iron recovery for four stages of flotation in conventional cells. It was shown to be particularly important to operate the columns to recover a maximum of the quartz gangue into the froth. It was noted that there are often problems in scale-up of laboratory columns to plant scale, because the increase in height and the decrease in the ratio of height to diameter at the larger scale allows more axial mixing and bubble coalescence, both of which degrade the column performance. Horizontal baffling was shown to improve column performance by reducing axial mixing and breaking up large bubbles, and so the use of such baffles in the reverse flotation application was investigated.

Jan 1, 2007

By C. -G. Zhang

This paper presents the results of a study on cellular acclimation of Acidithiobacillus ferrooxidans to sulfur biooxidation in terms of cells growth and changes in surface properties and morphologies of both cells and sulfur particles. The results showed that A. ferrooxidans cells were grown faster and demonstrated higher concentration in the soluble thiosulfate substrate than in nonsoluble hydrophobic S0 substrate. The results showed that A. ferrooxidans cells acclimated to the sulfur biooxidation by actively expressing some extracellular polymers substance and maybe some outer membrane proteins that modified the surface properties of both sulfur particles and the cells themselves. In addition, the results showed that the A. ferrooxidans cells were able to dynamically adsorb to or desorb from the surface of sulfur particles. The cells aggregating onto the S0 surface enhanced the use of S0 substrate by the bacteria cells. This mode may be one of the most important characteristics for the better growth and propagation of the cells in solid sulfur-containing media.

Jan 1, 2009

By Mark Rybak

On Aug. 31, 2006, Tropical Storm Ernesto hit the city of Richmond, VA. The Battery Park area was hit particularly hard, as flooding forced an evacuation of the area. A large sinkhole collapsed a sewer line in the Battery Park area, blocking the pipe and causing more serious flooding. This article describes the fast track design, bidding and construction of an emergency tunnel to bypass the collapsed sewer. Innovative value engineering, tunneling and shaft-sinking methods and final lining design all contributed to the success of this project. The storm inundated Richmond, VA with up to 305 mm (12 in.) of rain that, in some areas, caused widespread flooding and damage. One of the hardest hit areas of Richmond was Battery Park. A major trunk sewer in the Battery Park area collapsed and caused local combined sewer and stormwater flooding. The collapsed sewer was a 2.4-m x 76-mm (8-ft- x 3-in.-) wide by 2.7-m- x 152-mm- (9-ft- x 6 in.-) high arch sewer that was constructed in the 1920s and later filled over with municipal solid waste and a soil fill cap to cur-rent elevations. A sinkhole was created in the area of collapse approximately 18 m (60 ft ) deep and 31 m (100 ft) in diameter. This caused the existing arch sewer to become blocked. As a result of this blockage, contaminated floodwaters reached depths in low-lying areas in excess of 8 m (25 ft).

Jan 1, 2008

By Robert P. Kennedy, Andrew H. Merritt, Edward J. Cording, Thomas R. Kipp

INTRODUCTION Measurement of certain data associated with nuclear testing necessitates the reception of waves at the instrument location which are unaffected by reflection off internal structures or tunnel surfaces. Therefore, in order to provide necessary facilities for the fielding of experiments in support of the underground nuclear testing program, the Defense Nuclear Agency (DNA) commissioned a cost and feasibility evaluation pertaining to the design and construction of large underground cavities in Rainier Mesa. The effort included research into past experience pertaining to the excavation and support of large underground caverns, assessment of the geological conditions which exist in Rainier Mesa, preliminary design of the chambers and their rock support systems based upon the geological setting, development of mining plans for the excavation of the caverns, and estimation of the cost and manpower schedule to complete construction. This paper summarizes the results of the feasibility evaluation. The investigation was limited to modified hemispherical configurations ranging in size from 24.4 to 91.4 m (80 to 300 ft) in diameter. Two cavity support systems were considered. The first employs internally installed rockbolts as the means of primary rock support while the second involves the use of annular tendon galleries located above the chambers from which primary support members are introduced prior to general excavation. The internal support configuration was considered for cavities with spans of 24.4, 36.6, 48.8, and 54.9 m (80, 120, 160, and 180 ft) while the external support configuration was considered for cavities with spans of 54.9, 73.2, and 91.4 m (180, 240 and 300 ft).

Jan 1, 1979

Things are going well in the mining and construction industries world-wide. So good are things that from April 23 to 29 more than 500,000 visitors involved in those two industries attended the bauma 2007 Trade Show in Munich, Germany. Bauma is an international trade fair for construction and mining equipment that took place at the New Munich Trade Fair Center. It is hosted by Munich once every three years. This year was the most successful bauma ever and further strengthened the shows position as the world leader in the field.

Jan 1, 2007

By D. J. Pyra, J. Kudelko, Korzekwam W.

Polkowice region (Lower Silesia, Poland) is an area, where the copper mining activity started about 40 years ago and new technologies were applied. There are 3 underground mines, 3 processing plants, tailings pond (the biggest one in Europe), pipelines for flotation waste transport, railways. Although new technologies were applied during the copper ore exploitation, the environment in this area were polluted mostly by dust containing copper, lead, zinc and arsenic. Estimated values of heavy metals in polluted soils were compared to the natural contents of this metals. The geochemical background for Polkowice area was defined. The pollution zones occur around mining facilities. Copper ore exploitation and processing is planned for the next 20-40 years depending on market situation. After mines and other facilities closing the most important problem will be sustainable development of this area. To evaluate the scope of revitalization activities the analysis of recent soil environment condition will be necessary as well as forecasts for pollution migration. Geostatistic methods used also in mining will be very helpful for this task.

Jan 1, 2005

By J. P. H. Steele, M. U. Ozbay

As mining operations progress toward tele-mining and autonomous procedures, the need for machine performance monitoring increases. Presently, through a combination of vision, sound, and other subjective observations, an operator attempts to optimize the mechanical excavator’s operation. As the operator is moved away from the face in the case of tele-mining or completely removed for autonomous operation, the qualitative sensory input is lost. This lost information must be replaced with quantifiable sensory input. Chip formation detection may be a suitable replacement sensory input. Chip formation can be predicted with high confidence (>80%) through the analysis of the load waveform associated with the bit/rock interface.

Jan 1, 2002

By J. Drelich

The highly-efficient and economically-feasible technology for bitumen recovery from US oil sands using a water extraction approach was developed at the end of the last century. This water-based bitumen extraction process has been optimized based on observations and analysis of microscopic mechanisms of bitumen release from oil sands and the bitumen transfer to a froth product as well as measurements of interfacial properties of bitumen. The wetting mechanisms that occur in the diluent-assisted water-based processing of US oil sands include bitumen film rupture and recession on sand grains and bitumen transfer to nucleated and injected gas bubbles. These mechanisms are reviewed in this contribution.

Jan 1, 2007