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By Peter Campi, Harry R. Asche, Ian P. Callow, Edmund G. Taylor, P. Scott Smith

The US$1,850 million EastLink project is a 39km tollway and includes twin 3-lane,1.5km long, undrained driven tunnels. The hard rock tunnels are being built to avoid passing the motorway through the Mullum Mullum Valley and so to help preserve the unique flora and fauna in the area. This paper describes several of the key issues in the tunnel design and construction, including: the integration of the temporary support design with the Contractor’s tunnel excavation and support procedures, including sharing of responsibility between the Designer and Contractor for support type selection and the production of a project specific rock mass classification system to enable more objective determination of ground conditions. detailed hydrogeological assessments during the design and construction phases to allow confirmation of design loads for the tunnel lining design and the various suite of waterproofing tools in order to meet the project inflow requirements. development of a pre-cast invert solution to the main tunnel secondary lining to enable faster lining construction and to minimize risks to the tunnel membrane associated with fixing reinforcement and construction traffic.

Jan 1, 2007

By Joseph J. Feiler

Historical mining operations in Colorado and other western states have resulted in thousands of remnant mine openings. Many are sources of metals loading and acid water generation in surface and ground waters. It is estimated that more than 965 km (600 miles) of streams in Colorado have been impacted by past mining activities. The Animas River watershed in southwestern Colorado is one of the most heavily affected areas in the state. Abandoned mine features pose significant safety hazards to those who enter them. These hazards can include bad air, unstable rock or falls into open shafts, stopes and winzes. Backcountry skiers and snowmobile enthusiasts are particularly vulnerable to falls into snow covered mine openings.

Jan 1, 2006

The National Institute for Occupational Safety and Health conducted laboratory and field tests to evaluate the effectiveness of dust collector bags for reducing dust liberation and operator exposure from a roof bolter?s dust collection system. The laboratory tests evaluated the bag?s effectiveness to contain dust and the effect on canister filter loading in both a bag and bagless condition. The dust emissions from the collector?s exhaust were also measured in each condition during laboratory testing. Laboratory results show that nearly 100 percent of the test dust fed into the collector was captured by the dust bags. Loading and pressure drop on the dust collector?s canister filter is greatly decreased when using the bags, enabling longer periods of drilling without filter removal/cleaning. The field results showed that, even though dust standards were met, respirable dust in exhausted emissions was reduced around the bolter. Laboratory and field results show that benefits from use of the bags are realized in all areas of operator exposure.

Jan 1, 2008

By None None

Life as a mining/mineral professional doesn’t leave much time for perusing 20-page technical papers. Yet, being technologically savvy is part and parcel of a successful career in this industry. What’s an intelligent, well-informed person to do?

By D. Rutledge

Discrete (digital) signal processing techniques are proving to be very valuable tools for miners using the block cave method. Waveform analysis of different measured signals associated with active mining provides valuable information on production dynamics and safe operation of the mine. For example, correlation of the three-dimensional surface displacement velocity waveform and the production output waveform reveals a remarkably predictable time-varying physical process. In this paper, the authors discuss the signal processing techniques used to study these relationships, as well as the related implications for mining.

Jan 1, 2008

In 2005, CANMET-MMSL used its pool of expertise in ground control, open pit and underground mine engineering, mineral processing, information technology and applied mineralogy to launch a mine-to-mill research project. The objective of the project was to optimize the distribution of rock breakage energy among blasting, crushing and grinding activities, thereby maximizing the efficiency of energy utilization within comminution processes. Tests were designed to demonstrate that this approach could reduce energy consumption, thus contributing to the reduction of green house gas (GHG) production in the Canadian mining industry. The project was accomplished in collaboration with DynoConsult and Dyno Nobel Canada Inc., a world leader in commercial explosives. Data analysis from 12 blasts (six with electronic and six with pyrotechnic detonators) in three different geological formations of a quarry (soft, medium and hard rock) shows that electronic blasting technology increases rock fragmentation by 15% (in hard rock) to 20% (in soft rock). A more uniform rock fragment size distribution is also obtained. The impact of the improved quality blast product on downstream processes of the quarry is a productivity increase of 5% in rock excavation and transportation, an energy reduction of 10% at the primary crusher and an increase of 15% of the primary crusher throughput. Extended to the Canadian mining industry, such results would represent a GHG emission reduction of about 0.05 Mt/y. A soft-sensor prototype, based on primary crusher data (i.e., energy consumption, throughput, feed and product size distribution) and a simplified computerized process model, was developed for on-line measurement of the rock operating work index. Additionally, 385 rock samples and specimens were collected and prepared to determine the tensile and compressive strength of the rock material, to evaluate the aggregate crushing work index and to examine the development of micro- and macro-fractures by means of binocular and SEM microscopy. Blast-induced rock damage was evaluated at the end of the laboratory-testing program. Even though a reduction of rock hardness of around 30% was observed after blasting, the impact of the blasting method (i.e., use of electronic or pyrotechnic detonators) on the induced rock damage could not be observed. It is either absent or not perceptible with the accuracy of the measuring techniques and the number of samples analyzed.

Jan 1, 2008

By Stig Eriksson

In Switzerland two major railway systems as shown below in Figure 1 has recently been completed or is under construction: ¦Lötschberg, south of Bern which was commissioned in 2007 ¦Gotthard, south of Zurich which is scheduled to be commissioned in 2016The aim is to increase the transport capacity of the railway system and to transfer more transport of goods to the railway by offering transport of trailers and lorries on the new railway systems. It will have a positive environmental impact but also improve the congested traffic situation of the highways in north-south directionThe Gotthard tunnel is totally 57 km (35 mile) long and the Lötschberg tunnel is 35 km (22 mile) long. Both tunnel systems consist of two parallel single track tunnels connected with cross tunnels at every 333 m (1 093 ft). Additionally there are cross-over tunnels and caverns for installations and operation. In the Lötschberg tunnel, the majority of the excavation has been by Drill & Blast and in Gotthard tunnel the major part is being excavated by TBM.

By Wojciech Klecan

Cobb County, located on the northwest side of Atlanta, GA, is continually growing and, like many other metropolitan areas, it needs to increase the capacity of its waste water system to meet future demand. The Cobb County Water System (CCWS) is the responsible agency for water distribution, waste water collection and treatment in most areas of the county. CCWS, one of the most progressive agencies in the metro-Atlanta area, is addressing its future waste water capacity needs in the southern part of the county with the construction of the South Cobb Tunnel and Pump Station. This project consists of an 8.8-km- (5.5-mile-) long, 8.2-m- (27-ft-) diameter, tunnel boring machine (TBM) excavated waste water storage and conveyance tunnel; six tangential vortex-flow intakes ranging from 1,533 to 5,700 L/s (35 to 130 mgd) peak flow capacity, two construction shafts, six 1.8-m (6-ft) finished diameter connecting tunnels ranging in length from 6 to 975 m (20 to 3,200 ft) and a 5,700-L/s (130-mgd) wet/dry pit pump station. The pump station will have a semi-circular wet well with a dividing wall that extends almost to the top of the shaft and a spilt dry well for reliable operation. Roller gates will control the flow to the wet well from the tunnel. The pump station will have six 1,420 L/s (32.5 mgd) pumps and two sets of stair wells and elevators. With a finished diameter of 32 m (104 ft) and a depth of 62 m (204 ft), this is the largest pump station shaft constructed so far in Georgia for the dewatering of a waste water tunnel. The pump station shaft was also the highlight of the well attended and successful 2009 Shaft Design and Construction Short Course held in Atlanta, Sept. 10-11. The two-day course was sponsored by the Underground Construction Association of SME and Pennsylvania State University and concluded with a field trip to the pump station shaft. The tunnel starts south of the city of Austell and finishes at the South Cobb Water Reclamation Facility (WRF), located on the banks of the [ ] Chattahoochee River just north of Interstate 20 (Fig. 1). The South Cobb Tunnel will run 30 to 137 m (100 to 450 ft) below the surface, with an average depth of about 91 m (300 ft), through metamorphic rocks (Fig 2). The construction contract was awarded to Shea-Traylor JV with the lowest bid price of $305 million and notice-to-proceed was given on July 14, 2008. Jordan Jones & Goulding, Inc. (JJG) is the project designer and performed the geotechnical investigations. Parsons/Jacobs Associates is the construction manager. The South Cobb Tunnel is CCWS?s second deep hard rock tunnel. The 15.3-km- (9.5-mile-) long, 5.5-m- (18-ft-) diameter TBM excavated the Chattahoochee Tunnel was the first deep tunnel to be construced in Cobb County. Construction began in 2000 and the project was completed four years later. It is located about 16 km (10 miles) northeast of the South Cobb Tunnel in similar geology. It was designed by JJG to meet east Cobb?s long-term waste water capacity needs and provide flow equalization to the R.L. Sutton WRF. The Chattahoochee Tunnel was named ?Outstanding Civil Engineering Project of the Year? by the Georgia Sec-tion of the American Society of Civil Engineers in 2006.

Jan 1, 2009

By A. R. Biggart, A. Walters, G. J. E. Kramer

The Owner Procurement Process or OPP is a proven, viable alternative contract delivery method that is potentially applicable to many tunnel projects. Using the OPP, the owner specifies and procures major tunnel construction items such as tunnel boring machines and tunnel linings and provides them to a tunnel excavation contractor in order to manage risk and accelerate project schedule. However, due to industry perceptions regarding potential owner risk, it is seldom considered or is rejected out of hand. In fact, past performance demonstrates that the process significantly minimizes owner, contractor and over-all project risk and mitigates the impact of any claims and differing site conditions. The paper outlines how the process should be structured to achieve schedule, cost, quality and risk management benefits. Potential and perceived disadvantages are discussed and how the process can be structured to mitigate or avoid them. The planned implementation of this process on the tunnels for the Silicon Valley Rapid Transit Project in San Jose, California is discussed.

Jan 1, 2005

The safety of personnel is the most important matter during a mine fire. However, there is not enough research on a case when a fire occurs near a shaft and the behavior of the fire gas is not well understood. Therefore, a series of experimental study using a scaled ventilation circuit model was carried out. The behavior of ventilation air during a mine fire near a shaft was investigated. The model consists of two vertical shafts, three horizontal ducts connecting the shafts and an exhaust fan from the shaft bottom. The cross section of the shaft and duct is a square of 200×200mm. The height of the shafts is 3400mm. The length of the ducts is 1540mm. The lower duct is set at the same level as the shaft bottom. The middle and upper duct are set at 750mm and 1760mm above the shaft bottom respectively. The airflow rates through the ducts can be adjusted by regulators installed in each duct. The behavior of the fire gas was measured by anemometer, thermometer, and visualized using laser light .The air was ventilated downward in both shafts before the initiation of the fire. Some amount of fire gas of high temperature rose upward gradually along the shaft wall regardless of the downward ventilation after the initiation of the fire. Then the direction of main ventilation air suddenly reversed upward in the shaft. The direction of ventilation reversed in many places in the model and the fire gas reached even the part not anticipated.

Jan 1, 2009

By B. A. Ridolfi, S. M. Alvarez

The Moon Creek Reclamation Project provides a case study in the development of creative cleanup solutions for an abandoned lead and zinc mine and mill site located in northern Idaho. Innovative design features include construction of a 88,000cubic yard combined waste containment facility on soft in-situ tailings, water-balance cap, limestone gravel drains, a geocell mattress for stability, and a below-grade scour protection berm. The stream, including a wetlands buffer, will be relocated within an existing road alignment and rehabilitated to provide trout habitat. These elements allow for the integration of reclamation and stabilization measures into an effective site design.

Jan 1, 1999

By S. J. Benson

The Harts Range deposit, owned by Olympia Resources is located some 130 kms northeast of Alice Springs, in central Australia (part of Australia’s Northern Territory). The core economic minerals here are industrial grade garnet and alumino magnesio hornblende (AMH). The resource contains an estimated 2.3 million tonnes of recoverable garnet and 6.2 million tonnes of recoverable AMH, making Harts Range one of the most significant abrasive medium deposits in the world. Part of the general marketing axiom of Olympia Resources is to make high quality products from the garnet and also a special series of blended garnet/AMH products to match the needs for other sectors of industry. The deposit mineralization is of alluvial origin and thus, requires no significant liberation regimes. Over 50% of the head feed is in the form of SiO2/quartz and as much as 17% is –63micron clay slimes and mica. Original pilot scale testwork for flowsheet development centred around fairly conventional wet gravity systems, with spiral concentrators being the pre-eminent separating device. To a point, this type of flowsheet was going to achieve some of the aims albeit fairly predictably. The one area that this circuit would be very limited though is in the recovery of the very coarsest of the medium SG minerals. This was going to be a very important and longer-term costly flaw. Amongst the highest demand, greatest value of products to be produced will be the range of garnet & AMH in the +600 microns sector. A flowsheet dominated by spirals would be fated to forfeit a significant proportion of these coarse minerals to tails. At the Outokumpu Technology P/L test facilities in Perth, testwork was conducted using a pilot scale Floatex® Density Separator, the LPF-230 model. Using a twin stage approach, whereby a primary Floatex® underflow reports directly to a secondary Floatex®, recovery of the economically important +600 micron garnet was increased from 65% in the spirals-only flowsheet to 95% using the Floatex® based flowsheet. Finally, the other significant aspect of this approach is in substantial simplification of the circuit required and a huge reduction in plant footprint. Also, the nature of using hindered settling provides substantial opportunities for process control and automation.

Jan 1, 2005

By L. M. Lenahan, J. D. Sheets

INTRODUCTION The Raleigh-Durham International Airport (RDU) in North Carolina is the fourth largest airport in the southeast region of the United States. The Raleigh-Durham Airport Authority is currently underway with planning, designing and constructing are placement Passenger Terminal as part of the Major Capital Improvements Program at Raleigh Durham International Airport. The Terminal C Expansion and Renovation Project will replace the existing Terminal C structure with a new processor building and concourse. The project is separated into several contracts. The early stage contracts are constructing a west side storm water management facility, relocating taxiways, installing new drainage systems, installing new aircraft apron pavement, Demolition, the Central Energy Plant and Early Foundations. The later projects are the Terminal Building, Passenger Boarding Bridges, Information Technology Systems and Integration, Furniture, Furnishings & Equipment and Specialty Millwork. The Terminal Building will be constructed in two phases. Phase 1 constructs the north half of the new terminal. Airline operations will move to the new terminal at the completion of this phase. Phase 2 completes construction of the south processor building. The full build out of the project, subject to funding availability, will replace the remainder of the south concourse. The Program’s primary focus is to replace the existing passenger Terminal C with a new terminal that will provide more passenger gates and larger passenger screening, ticketing and baggage handling facilities. The planning for the New Terminal C Program began in 2002 with construction starting in March, 2003. The continuing growth of passenger airline travel in the Raleigh/Durham metropolitan area requires RDU to expand its facilities to keep up with the present and future growth within the Region. In October of 2002, the RDU Airport Authority selected Parsons Transportation Group as the Program Manager/Construction Manager to help assist in the development of the Terminal C expansion program. RDU Airport Authority selected the Seattle Washington Office of URS Corporation as the Engineer of Record for the West Side Storm Water Management Facilities. The Westside Storm Water Management Facilities Project became one of the early critical path activities of the overall RDUAA Terminal C Expansion Program. The Briar Creek Reservoir had been constructed to accommodate storm water runoff to the west of the Airport. The existing 1.5 m culvert that drained runoff from the airport terminal (area) to the reservoir was insufficient in supporting the additional flows

Jan 1, 2005

By X. Zhou

In this study, the cyclonic static microbubble flotation column (FCSMC) was investigated for fluorite beneficiation. The structure and principle of the specially designed column are described. Fluorite samples from the tungsten separation tailings of the Shizhuyuan Mine, Chenzhou, Hunan Province, P.R. China, were tested using a small-scale continuous flotation test unit, and concentrates with a fluorite grade higher than 98% were obtained. One rougher and three cleaner stages in the FCSMC achieved the same separation performance as one rougher and eight cleaners in conventional flotation cells. This greatly simplified the flotation circuit and reduced operating costs.

Jan 1, 2007

By Les Gutzwiller

Fan applications in the mining industry have changed during the last 70 years. In 1922, J.R. Robinson authored a technical volume entitled Practical Mine Ventilation. At that time, atmospheric control had only recently shifted from natural to mechanical. The large, mechanical draft fans that were used then were centrifugal. The fans ran at low speeds, about300 rpm. Most were steam-engine driven. In the late 1920s and early 1930s, mines became larger, increasing the pressure and volume requirements of the fan equipment. Axial fans were designed to run at much higher speeds (710 to 880 rpm) and were driven by electric motors. They were also smaller and less expensive to install than the cumbersome centrifugal units. However, changes in mining have resulted in progressively higher static-pressure requirements. So centrifugal fans are once again proving to be a good choice.

Jan 1, 1999

By Andrew E. Nevin

The government of India convened a precedent-setting meeting in New Delhi on Nov. 12, 2001.The meeting brought together regulators and the mining industry in an attempt to fix the industry’s mine development problems in that country. More than 150people attended the all-day session. Ram Vilas Paswan, Minister of Coal and Mines, chaired the meeting. Ravi Shankar Prasad, Minister of State for Coal and Mines, was also present. The secretary of the Department of Mines and the Joint Secretaries and Additional Secretary also participated. The Department of Mines’ mandate is for economic growth: to get new mine development going and to make investment in mining attractive for both domestic and foreign-owned companies.

Jan 1, 2002

By B. J. Dave, Ashok J. Desai, Allen J. Hulshizer

This paper presents various design and construction considerations involved in developing an underwater installation of lined, large diameter shafts not known to have been previously accomplished for the diameter size, depth or ground conditions identified with the Seabrook Power Station. Outlined approach provides for driving tunnels independent of shaft sinking operation, permits the use of prefabricated shaft lining and incorporates a safe dry tap method for connecting the shafts to the tunnels. INTRODUCTION The Seabrook Power Station, located two miles inland from the Atlantic Ocean, at Seabrook, New Hampshire, is a two unit, nuclear powered, electric generating plant, each unit having a capacity of 1150 megawatts (electric). Typical to all steam driven generators is the requirement for large quantities of water. Requirements for the Seabrook Plant will be met by intaking and discharging approximately 850,000 gpm of ocean water at a considerable distance from the shore line in water depths that render the environmental impact inconsequential. Obtaining, conveying and discharging such large quantities of water represents a major undertaking, particularly under today's environmental controls. Tunnels are well suited to reducing the environmental impact at the Seabrook site by conveying the water about 250 feet deep under the salt marsh (a valuable ecological feature) and under the beach well out into the ocean without any noticeable ground surface disturbance. An alternate approach utilizing trenched piping would have created some disturbances and was environmentally less desirable. The tunnels connect to intake and discharge

Jan 1, 1976

Syncrude Canada produces a large part of Canada’s crude oil supply. The company processes about 225,000 bbl/day. The oil produced is used for jet and automobile fuel, home heating oil, plastics and other consumer synthetics. Crude oil is produced through a process of mining, extracting and upgrading bitumen. A rich supply of bitumen is contained in the Athabasca oil sands deposit in northern Alberta. Tailings from the bitumen processing are sent to a settling basin.

Jan 1, 2000

By W. Rogers

Blast-induced rock mass displacement can have a significant impact on ore loss & dilution. The mischaracterisation of the grade boundaries both prior to, as well as a result of blasting can lead to significant financial losses on account of ore loss and dilution. Ore dilution occurs when waste material is miscategorised as ore and sent for processing or stockpiling, diluting the run of mine head grade and recovery. Ore loss takes place when valuable mineral is miscategorised as waste and sent to the waste dumps, thus never being processed and recovered. Extensive research has been conducted at the University of Queensland over the last fifteen years to understand the impact of blast movement on ore loss and dilution. Recent outcomes of this research have developed innovative tools and techniques to measure and model blast movement. These techniques have been implemented at Ahafo gold mine in Ghana to understand blast movement dynamics and to implement solutions to reduce blast-induced ore loss and dilution. These solutions are validated through controlled trials and have been incorporated into site standard operating procedures to sustain the benefits.

Jan 1, 2012

By M. D. Johnson

Mina Santa Rosa, in west central Panama, is the first large-scale gold mine in Panama and will soon be the largest single-mine gold producer in central America (Fig. 1). At full production, the mine will process 1.8 Mt/a (2 million stpy) of ore and produce more than 1.8 t/a (60,000 oz/year) of gold and 9.3 t/a(300,000 oz/year) of silver. Mina Santa Rosa is a subsidiary of Greenstone Resources of Toronto, Ontario. Freeport-McMoRan geologists first visited the area in 1985. Their rock chip sampling adjacent to old shafts and adits confirmed widespread gold and trace element geochemistry anomalies. Surface mineralization appeared to be localized in and adjacent to narrow veinlets. However, they recognized astructural setting similar to the Nevada Tertiary volcanic-hosted epithermal gold systems.

Jan 1, 1996