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By M. Rice, M. Stanley, J. Marlow

Arizona construction aggregate industry remains in the crosshairs of public debate, caught between the need for aggregate-based building materials and alternative, high-value land-uses. To better manage lands and improve land-use decisions, the Arizona State Land Department has need for a system to assess potential aggregate resources on State Trust lands, and assign dollar values accordingly. Thereafter aggregate values can be compared to residential, commercial, agricultural, recreational, and habitat values -- in a determination of highest and best land-use.

Jan 1, 2002

By S. K. Kawatra, K. J. Shoop, T. C. Rao, T. C. Eisele

This study investigates the use of a horizontally- baffled column (7.6 cm inside diameter by 344.2 cm high) to reduce the ash content of a high ash bituminous coal. Tests were carried out to determine how the baffled column responded to changes in feedrate, reagent dosage, and feed quality, and to compare its performance with a conventional column installation in an operating plant. In this paper, the results of this investigation will be reviewed and discussed.

Feb 24, 1997

By Jean Habimana

Complex and distinct geological units spread along the 7-mile long 30-ft inside diameter Upper Rouge Tunnel CSO Control Project in Detroit, Michigan. Its construction is divided in two tunnel construction packages: The South Tunnel, to be driven in finely laminated weak TG Limy Shale, will be excavated by a shielded TBM with precast concrete segmental lining, while the North tunnel, predominantly in a relatively more competent geologic formation Antrim Shale, will be excavated by a main beam TBM with a two-pass lining system. The adits and deaeration chambers will be excavated by sequential excavation method. This paper addresses the process of selecting excavation methods and lining systems for shafts, tunnels, connecting adits, and deaeration chambers.

By L. J. Prosser, A. T. Iannacchione

Unfortunately from 1991 through 1995, 44 miners were fatally injured in the stone industry. Of these 12 occurred at underground mines from a total work force of less than 2,000 miners. Nine of these 12 miners were fatally injured in falls of roof or rib. A safer environment for the miners can be achieved by evaluating the nature of the hazardous ground and by developing more efficient and effective ground control strategies. Roof and rib conditions in the underground stone industry were observed and assessed at 33 mines in Illinois, Indiana, Kentucky, Maryland, Missouri, Pennsylvania, and West Virginia [(Figure 1)]. Hazard assessment indicated that those ground failures occurring under moderate to substantial overburden (> 30 m [l00 ft]) were caused by stress concentrations and geologic structures. Ground failures near the surface are caused by solution (water) processes. Selection of the mining horizon and mine layout decisions tremendously influence ground stability.

Feb 24, 1997

With unprecedented worldwide growth and increasing global demand for energy expected to swell by 60 per-cent in the next two decades, mining matters as much now, if not more, than it ever has. This was the consensus at the 110th Annual National Western Mining Conference presented by the Colorado Mining Association, Feb. 12-14 at the Westin Hotel in Denver, CO. The role of coal ? America?s most abundant energy source ? the future of uranium and its possible resurgence in the energy marketplace, the skyrocketing value of gold as well as the issues of health, safety, climate change, legislation and government?s role in mining were all discussed during the three-day conference that operated under the banner of ?Mining Matters.? Barbara Filas, chairperson of the 110th National Western Mining Conference, president of Knight Piesold Co. and former SME president, welcomed the record crowd with an inspiring speech in which she pointed out that although ?most normal folks don?t know what role mining plays in their everyday life, mining does matter. ?Our industry,? she said, ?matters to Colorado. It matters to Colorado because it is a $3-billion industry. It matters to the 13,000 people who are employed directly or indirectly by the industry and it matters to schools that receive more than half of the royalties that are generated by mining.? During discussions of mining?s place in Colorado, the western United States and the world, special attention was paid to coal, uranium and the future of energy. ?It is time to rethink our perceptions about coal,? said Mark A. Smith, president and chief executive officer of Chevron Mining Inc. He spoke during the opening reception in a presentation titled, ?Coal to Liquids: Bridging America?s Energy Gap.? Although coal is America?s most abundant, and cheapest energy source, it is also one of the most scrutinized because of the pollution it causes and recent, and heavily publicized, tragedies that have claimed the lives of some who mine it.

Jan 1, 2008

By Michael Day, Paul Kos, Scott Brinton

A hydrogeologic characterization and impact analysis was performed for a proposed quarry at the Hitch Rack Ranch located in the Little Turkey Creek watershed southwest of Colorado Springs, Colorado. Continuous multiple channel tubing, nested piezometers, stream flow measurements, and mapping of known seeps were used to define the three-dimensional potentiometric distribution and areas of groundwater recharge and discharge. Water balance considerations, mass balance calculations, and potentiometric response to earth tides and barometric fluctuations confirmed that the granite fracture system in the ridge area of the proposed quarry has an extremely low bulk hydraulic conductivity resulting in minimal groundwater discharge to sustain the baseflow of Little Turkey Creek. The Little Turkey Creek valley forms the major conduit for groundwater flow exiting from the upper part of watershed underlain by granite. This conclusion has significant implications with respect to mine planning to minimize projected impacts to the hydrologic system and preserve this recharge component to downgradient Denver Basin sedimentary deposits.

By Kristen E. Coose

Concrete is a mixture of a fine aggregate (sand), a coarse aggregate (gravel), cement, and water. Cement itself is the most expensive of the ingredients but generally amounts to only about 10% of the concrete mixture. Cement raw materials include calcium, alumina, iron oxide, silica, and gypsum. They are heated and chemically changed into clinker "minerals," which are then ground and shipped as cement. Each of the four main clinker minerals-tricalcium silicate, dicalcium silicate, tricalcium aluminate, and tetracalcium aluminoferrite-impart specific strength and compositional properties to the final concrete product. During hydration of the cement, chemical changes produce new minerals that include calcium silicate hydrate gel (C-S-H, the main constituent of hydrated cement paste), calcium hydroxide, and calcium, sodium, potassium, and sulfate ions, among others. Two main reactions can occur that may be deleterious to concrete. Normal cement pore solutions, in a hydrated cement, contain sodium hydroxide and potassium hydroxide. If these alkali concentrations are too high, they can react with the siliceous aggregate (alkali-silica reaction, or ASR) to form an alkali-rich calcium silicate hydrate gel (C-N+K-S-H), which, upon prolonged contact with water, can expand to crack the concrete. The other deleterious reaction occurs when the mineral ettringite (Ca6A12(S04)3OH12. 26H20) forms after the concrete is hardened (delayed ettringite formation) and cracks the concrete. Many of the concrete bridges and structures built in New Mexico in the past 20 years are in need of replacement due to deterioration. Many others constructed very early on in the century are still sound. By collecting and analyzing samples of both old and new concrete and good and bad concrete, we compared their differences on both a microscopic and macroscopic scale. Samples taken from concrete sidewalks, parking lots, drainage canals, spillways, and a railroad-trestle foundation have construction dates that range from 1923 to 1997. They were analyzed by electron microprobe and by petrographic microscopy. Cracks, air voids, and aggregate alteration were primary locations for investigation and analysis. Using the electron microprobe, ettringite was found in voids of most of the samples, both in good and bad concrete. This leads us to believe that ettringite formation is not causing distress in the concrete. There was one exception in which ettringite was found lining a crack. In this instance, ettringite may have the ability to further the cracking and cause distress. No alkali-silica gel was identified with the microprobe. Using the petrographic microscope in cross-polarized light, a light-brown material was observed that lined some of the air voids and cracks; however, exact mineralogic identifications were not made. Although many instances of chalcedony and other deleterious quartz phases were found, no clear evidence of ASR-gel deterioration was present in our samples using these methods. However, positive identification of the ASR gel was made on an in-place concrete near one of our sample sites and in several sample cores using a newly developed chemical test for the soluble potassium ions associated with the gel. The chemical used in this test is sodium cobaltinitrite, Na3Co(NO2)6.

Jan 1, 1999

Using a series-model of an automotive short range radar sensor (SRR) and a recently completed experimental radar system, field tests have been performed in a surface mine. It was examined, to what extent low-cost electronically scanning radar sensors can provide useful data for assistance systems on large scale mining machines. Simple sensors are useful for anti-collision safety zones or hopper car automation. The more complex and sophisticated experimental radar system using digital beam-forming can clearly detect and map the contours of trenches and slopes. The overall promising results refer to many more potential applications for electronically scanning radar in surface and underground mining as a reliable alternative to mechanical laser scanners.

Jan 1, 2007

By R. D. Williams

In spite of the increasingly polarized and politicized view of climate science and climate change in the United States, many of the principles behind the ?theory? of Anthropogenic Global Warming (AGW) or Global Climate Change (GCC) are in fact firmly established both in fundamental physics and detailed observations and are widely accepted elsewhere. The discovery of the earth?s ?greenhouse effect? dates back nearly 200 years to the work of French mathematician and physicist Joseph Fourier in 1824 and 1827. In 1872, John Tyndall an English physicist and mountaineer, described the capacity of various gasses to absorb radiant heat. He identified water vapor and carbon dioxide as the principal ?greenhouse? gasses. The work of Fourier and Tyndall was the foundation for the theory that increasing carbon dioxide (CO2) in the atmosphere might be responsible for an increase in global temperatures developed by the brilliant Swedish chemist Svante August Arrhenius in 1896. This was backed up by the additional work of Gilbert Callendar in the 1930s, and Gilbert Plass, Hans Suess and Roger Revelle in the 1950s. There is little scientific dispute about the physics by which this occurs: carbon dioxide in the atmosphere absorbs long wave radiation that would otherwise escape into space, thus warming the lower atmosphere and respective temperatures worldwide. The Intergovernmental Panel on Climate Change (IPCC), approximately 2500 climate scientists from around the world, has concluded that increases in carbon dioxide resulting principally from the burning of fossil fuels are responsible for most of the continuing increases in global temperatures (IPCC, 2007). NASA?s Goddard Institute for Space Studies (GISS) states; ?The ten warmest years all occur within the 12-year period 1997-2008? (GISS, 2009). 2009 was the second warmest year on record and 2010 was tied with 2005 for the warmest year on record (GISS, 2010, 2011). The science is in fact settled; the earth has not cooled since 1998 as some have claimed. It continues to warm as evidenced by not only surface temperature records but also ocean temperature records as well as changes in physical and biological systems (IPCC, 2007).

Feb 27, 2013

From the massive equipment that moves the earth, to the parts that keep the equipment moving, it was all on display for more than 35,000 people who at-tended MinExpo 2008 at the Las Vegas Convention Center Sept. 22-24. In the largest show in the illustrious history of MinExpo, the success of the recent commodity boom was reflected in the more than 55,700 hm2 (600,000 sq ft) of floor space that was jam-packed with nearly 1,300 vendors. Among them, the makers of the industry?s largest machines, displaying their latest and greatest trucks, shovels, excavators, drills and other mining equipment. During the nearly decade-long commodities boom, equipment makers have worked hard to keep up with demand while also investing heavily in research and development. The beneficiaries of this R&D is the end user who saw first-hand at MinExpo 2008 the many advances that have already been made in safety, comfort and productivity from all the manufacturers. R&D has also helped spark more talk of automation, which is being used already at some of the world?s largest mines. Caterpillar and Komatsu have worked with the technology in surface mining and Bucyrus and Sandvik are among the industry leaders applying the science of automation to underground mines. Technology has in-creased greatly since the idea of moving massive equipment remotely was first knocked around and the idea of entire fleets operating around the clock seems to be getting closer to reality. But, until that happens, MinExpo attendees were treated to a show that featured some of the most impressive current machines the industry has to offer. In the largest booth space of the convention, Caterpillar (www.cat.com) displayed the culmination of an ambitious $280-million dollar investment, with the introduction of its new mining fleet of four new trucks. The F-series was un-veiled with common features in safety, cabs, engines, frames and bodies and Tier 2 compliant engines. The F series also features a return to the electric drive option. ?When our customers asked us for improvements to our mining trucks, we responded by making a record investment in every single truck in our line, as well as the increased capacity to produce more of them,? said Cater-pillar group president Stu Levenick. ?New technologies have allowed us to make trucks more reliable, easier to maintain and more friendly to the operator and to the environment.? The 793-series is in the 218- to 227-t (240- to 250-st) class that will be available in both mechanical (793F) and electric (793F ac) versions. The electric drive-only 313- t (345-st) 795F was also introduced, while the flagship 797B truck is in the process of being replaced by the new 797F mechanical drive, maintaining its 345- to 363-t (380- to 400-st) target payload. Completing Caterpillar?s new mining truck line will be new versions of the 785 and 789 mechanical drive trucks. The next generation of trucks will be phased into production during the next two years, with the Cat ac drive models expected to go into production in late 2010. The $280-million in-vestment is Caterpillar?s largest commitment ever to the mining industry

Jan 1, 2008

By Bhaskar B. Thapa, Michael T. McRae, Johannes V. Greunen

This paper describes the preliminary design of the fourth bore of the Caldecott Tunnels along State Route 24 in Oakland, California. The paper focus is on two major aspects of the project: initial support system design and seismic design. The initial support system was designed based on the New Austrian Tunneling Method (NATM).NATM provides the required flexibility to accommodate the variable ground conditions in the weak, folded, and faulted rock along the alignment. The seismic design provides a final lining system that meets serviceability requirements for a 1,500 year seismic event with an estimated peak ground acceleration of 1.2g.

Jan 1, 2007

By Aram Grigoryan

This paper addresses historical aspects and construction sequencing of the subway complex under Columbus Circle in Manhattan; the structural elements of the rehabilitation and new construction; and the challenges associated with design and construction. PB is providing engineering services to New York City Transit (NYCT) for the rehabilitation of the 59th Street/Columbus Circle Station Complex that services over 150,000 customers daily. The project involves structural repairs, modifications and new construction requiring underpinning and temporary supports, custom framing details, and construction staging procedures to meet stringent limitations within the operating transit station and around the Columbus Circle street intersections.

Jan 1, 2008

By G. H. Glos

There was a time when an occasional failure of a tailings embankment was considered an acceptable risk associated with mining activities. This is not the case anymore. A major tailings failure today could result in the indictment of mine officials, huge fines and a possible site closure due to the loss of operating permits. As a result of this changed operational environment, tailings disposal facilities must be operated with these potential consequences in mind. Physical controls for tailings embankments are prohibitively expensive. However, the nuclear industry has developed a system of administrative controls as an alternative to physical controls. Administrative controls may be defined as control of actions, through organizations and management, using written procedures, record keeping, review and audit to assure operation of a facility in a safe manner (10 CFR 50). Administrative controls can reduce the cost of operating tailings impoundments, as well as increase the level of confidence in these facilities.

Jan 1, 1999

The Awareness and Preparedness for Emergencies at the Local Level (APELL) program is a process that helps people prevent, prepare for and respond appropriately to accidents and emergencies. APELL was developed by the United Nations Environment Program, in cooperation with industry groups, governments and local communities. Since its beginnings in1988, the program has been implemented in more than30 countries. APELL is a tool for bringing people together to allow effective communication about risks and emergency response. The program provides a common-sense approach to accident prevention and response.

Jan 1, 2003

Atlas Copco Wagner launched its ST1010 Scooptram load haul dumper. The ST1010 replaces the company’s Wagner ST-1000 Scooptram. The improvements to the Wagner ST1010 include increased reliability, ease of maintenance and driver comfort or ergonomics. The ST1010 has been redesigned and has added several new features and options not offered in the earlier model. These include anew boom design with side stops. Heavy reinforcements to the bogie offer better protection against the harsh working conditions in underground mining and tunneling. An auto lube system has also been added as has paint-on grip tread to reduce slips and falls during maintenance checks or repair work. Other features include a heavy-duty, auxiliary-fan motor, an isolated transverter, remote diagnostic pressure taps, a bolt-on battery box, raised air-intake, improved fuel-filter access for easier maintenance, larger wear-bars around the engine tub, and smaller, higher output batteries

Jan 1, 2000

By Kent C. Condie

Precambrian terranes in the Rocky Mountain region decrease progressively in age from the Archean Wyoming Province (> 2.5 b.y.) to the late Proterozoic in West Texas (figs. 1,2). Within the Wyoming Province, most dates fall near 2.7 b.y. although some are recorded at 2 3.8, 2.9, and 2.6 b.y. Although Penokean (- 1.8 b.y.) deformation and plutonism are recorded in southeastern Wyoming, most Precambrian rocks south of the Wyoming shear zone, which separates the Archean and Proterozoic provinces, are < 1.76 b. years in age. Supracrustal rocks in Colorado, western Arizona, and northern New Mexico fall in the range of 1.72-1.76 b.y., those in central New Mexico about 1.65 b.y., those in southeastern Arizona and southwestern New Mexico about 1.70 b.y., and those in West Texas 1.1-1.2 b.y. The Wyoming Province is comprised chiefly of 2.7 or 2.9 b.y. tonalitic gneiss terranes intruded by 2.6 b.y. granites in the central and southern parts of the province. Supracrustal rocks are minor and include greenstone belts comprised chiefly of pillow- ed tholeiites and graywackes and remnants of quartzite-shale successions. Metamorphic grade in greenstone-gneiss terranes ranges from upper greenschist to amphibolite facies and in quartzite-gneiss terranes from upper amphibolite to granulite facies.

Jan 1, 2013

By T. H. Chan

As the University of Hong Kong and their advisors planned their new Centennial Campus it became clear that they would have to re-provide existing water reservoirs on an adjacent site with new salt water reservoirs located underground in two new caverns. The existing reservoirs are owned by the Water Supplies Department who provide salt water for sanitary flushing and a separate potable water supply for regular use. Although underground reservoirs had not previously been adopted locally, the planning has been completed to a tight schedule and the construction is well advanced. The need to preserve historic buildings imposed constraints, as did the requirement to minimise potential construction nuisance for the local community and environment. This paper presents the background to the project and the work carried out to develop an innovative, sustainable and environmental acceptable solution. Construction progress to date is also presented.

By F. L. Pirkle

A heavy-mineral deposit about 1.6 kilometers (I mile) in length and averaging about three meters (10 feet) in thickness is exposed approximately130 kilometers (80 miles) east of Denver, along Interstate 70, in Elbert County, Colorado near the town of Limon. The deposit is exposed in a geomorphic feature known locally as Titanium Ridge. The dominant heavy minerals, accounting for about 70% of the total heavy mineral suite by weight, are ilmenite, garnet, and zircon. The mineralized zone appears in a series of visually interpretable facies that are stacked vertically and represent subtidal, forebeach, backbeach, washover fan, and aeolian depositional environments. These paleoenvironments are analogous to depositional environments represented by a modern heavy-mineral bearing facies tract on St. Catherines Island, Georgia. Thus, Titanium Ridge provides evidence that heavy-mineral accumulation models for late Cenozoic deposits in the Georgia and Florida coastal plains are applicable to heavy-mineral deposits of the Western Interior subsurface and, by implication, the Western Interior Seaway, extending from Mexico to the Canadian Arctic.

Jan 1, 2011

By W. K. Callaway

The need to increase ore recovery and pillar stability caused the Magmont Mine staff to investigate the use of sandfill to accomplish both tasks. The use of hydraulically stowed classified mill tailings as a subsidence preventative will be discussed as well as the use of sandfill in pillar recovery and as a part of the regular mining cycle.

Jan 1, 1986

By Antonio Raschillà

On the 2nd of June 2007 SELI S.p.A. started the excavation of Beles Tailrace Tunnel (Ethiopia). The new 8,07 m diameter DS Universal TBM utilized for the tunnel excavation was manufactured by SELI S.p.A. and allowed the installation of 30 cm thick concrete lining, contemporaneously with the excavation of 7,200 m of tunnel. The greatest part of the tunnel alignment was excavated in hard and sound basal-tic rocks. The paper describes the main steps of the tunnelling operations which led to a remarkably rapid excavation, with a peak production of 36 m / day and a final break-through achieved 46 days ahead of the contractual deadline. Furthermore the paper describes the work and logistic organization that was set up to efficiently perform the mechanized excavation in the very remote area of the project.