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By Roy J. Leonard

Two small diameter sewer tunnel projects being hand dug under major highways in the Greater Kansas City area encountered problems which were unforeseen from the geotechnical engineering information supplied with the contract documents. Both tunnels were being excavated by experienced crews using steel liner plates. One required the use of compressed air for completion, while the other required poling boards. Both contractors overran their budgets and filed changed condition claims, and this promoted further geotechnical engineering investigations. Fissured clays beneath a water table were encountered at both sites, but the character of these clays differed; however, both were inadequately described in the original geotechnical engineering reports.

Jan 1, 1987

By D. M. Larsen

Since start-up in 1985, the Cannon Mine has produced and shipped a 170-g/ton (5 oz/ton) gold flotation concentrate to various smelters for gold and silver recovery. Several processes have been investigated to economically produce done' at the mine site from the refractory concentrate. This paper describes laboratory and pilot scale test work used in the process design and engineering. feasibility study of a 73-t/d (80 stpd) pressure oxidation and carbon-in-leach (CIL) facility. The designed pressure oxidation circuit utilizes a series of verti¬cal autoclave units operating at 170°C (338F) and 1.4 MPa (200 psig). Projected operating costs are discussed.

Jan 1, 1993

By Timothy C. Siegel

Drilled displacement piles (also known as augered cast-in-place displacement piles or augured, pressure grouted displacement piles) are installed by the displacement of soil and subsequent placement of fluid cement grout within the evacuated volume. Depending on the soil grain-size characteristics, soil behavior, in situ soil density, pile spacing, and pile diameter, the installation process can result in measurable densification and an increase in lateral stress. This paper examines the conditions prior to and following the installation of drilled displacement piles at sandy sites using the cone penetration test. The data support that the installation of drilled displacement piles results in a substantial increase in tip resistance.

Jan 1, 2007

By David Corkum, David Hatem

Subsurface construction projects are risky ventures and the decision to deliver a project using the Design-Build model does not eliminate those risks. Differing site conditions, inadequate design, and delays will continue to plague some projects. The Design-Build procurement model, however, presents a broad opportunity to allocate those risks much differently than in the familiar Design-Bid-Build model. Starting with a philosophical approach to risk and reward, this paper discusses the continuum of possible risk allocation strategies. It concludes with a proposed optimum strategy in terms of the project’s overall economic efficiency, and points to the dispositive contractual provisions that serve to contour the risks.

Jan 1, 2003

By E. V. Given

Designing a tailing dam is a major step toward fully integrated mill operation. In the case of large concentrators considerable planning is necessary, and the site of the tailing disposal area may very well dictate the location of the concentrator itself. Before a suitable location can be selected several pertinent factors should be investigated: estimated life expectancy of the mine and, if possible, approximate total tonnage; knowledge of daily mill capacity; and the possibility of future mill expansion. In addition, the area should be able to store tailing for many years and, from a cost and maintenance stand- point, gravity flow will probably be desired.

Jan 7, 1959

By M. R. Leonard

It is estimated that between 5 and 15 pounds of solid waste are generated monthly by each individual. Finding a final resting spot for such waste is an important matter. In the "good ole days," dumps of every description and condition were available. Not so now. Almost all states have adopted and are enforcing strict regulations regarding the disposition of solid waste. Many companies, owing to the nature of their business, have potentially good waste-disposal sites available. Cleveland Quarries Company falls in this group; but in spite of our having state and county permits, opposition by the local community denied us the opportunity to provide a needed local service.

Jan 1, 1974

Saxonvale mine is a multi bench open pit coal mine developed to its Stage I capacity of 1.75 Mt/y of run of mine coal. Detailed engineering studies for the mine commenced in April 1980, approval to proceed with the development was received in July 1980 and first coal shipments were made in April 1982. The engineering and project management of the mine development was carried out by BHP Engineering. This paper outlines the design and site administration for the development and describes both the organisation structure and the control and administration procedures used by BHP Engineering to ensure that the project was Successful.

Jan 1, 1983

By Henry Brehaut

The International Network for Acid Prevention (INAP) was formed in 1998 by 17 international mining companies to promote significant improvements in the management of sulphidic mine materials and the reduction of liability associated with acid drainage through knowledge sharing and research and development of technology. Since its inception two panels have been formed to identify and move forward with research projects and eight networks have been constituted to initiate interaction and knowledge sharing within the membership in specific areas of technical interest. An INAP web site has been developed to facilitate the sharing of information and to encourage the exchange and development of new ideas.

Jan 1, 2000

By M. Kyzeridi

The paper presents a study on the reclamation of two mined-out bauxite open pits in the area of Kefali, Itea, Greece. The mining area has been reclaimed partially in the past, but its proximity to the town of Itea and a national road with tourist traffic, rose the interest to examine various scenarios for improving the landscape and the aesthetics of the site and introducing alternative land-use for recreational activities. Geospatial data were modelled using a Geographical Information System (GIS) that made it possible to study alternative proposals in terms of final landscape profiles, volumes required to be moved and the associated costs.

Jan 1, 2002

By D. M. Larsen, N. D. King

Since start-up in 1985, the Cannon Mine has produced and shipped a 170-g/ton (5 oz/ton) gold flotation concentrate to various smelters for gold and silver recovery. Several processes have been investigated to economically produce dore' at the mine site from the refractory concentrate. This paper describes laboratory and pilot scale test work used in the process design and engineering feasibility study of a 73-t/d (80 stpd) pressure oxidation and carbon-in-leach (CIL) facility. The designed pressure oxidation circuit utilizes a series of vertical autoclave units operating at 170°C (338°F) and 1.4 MPa (200 psig). Projected operating costs are discussed.

Jan 1, 1994

By E. Contestabile, B. von Rosen

On August 5th, 1998, a tractor-trailer carrying approximately 18,000 kg of blasting explosives, struck a rock face on the side of the road near the town of Walden, Ontario. Eye-witness accounts of the incident state that there was an intense fire for approximately 30 minutes before the detonation. The detonation caused severe damage to the tractor-trailer, shifted the pavement and caused blast damage to the rock face. A rock fragment was recovered almost 2.5 km from ground zero and a 70 kg piece of an axle assembly was recovered over 1 km from the site. Windows were cracked at distances of almost 3 km.

Jan 1, 2001

By D. A. Stanley, B. J. Scheiner, P. M. Brown

The Bureau of Mines (USBM), US Department of the Interior, has developed a method of dewatering clay slurries based on flocculation by high-molecular-weight polymers and water removal from the formed flocs using a trommel or hydrosieve. The exchange ion on the clays affects their dewaterability. Metal ions in solution and on the exchange sites of smectite clays are known to act as Lewis acids. Recent work has determined that these ions can be titrated with high-molecular-weight polymers. The relative acidity of the exchange ion and the basicity of the polymer determined by the new method give insight into the dewatering mechanism.

Jan 1, 1990

By Timothy J. Napier-Munn, David M. Weedon

A model of mineral liberation was developed using back calculation techniques to determine breakage/liberation parameters in a similar manner to the way breakage parameters are determined in the Population Balance Model (PBM). Comminution and liberation data was collected from grinding mills operating at Pasminco lead/zinc mine Broken Hill, and Mt. Isa Mines copper concentrator, Mt Isa, Australia. Laboratory scale single particle breakage tests on ore samples from these sites were undertaken using a twin pendulum breakage device. Break- age/liberation parameters were then determined for several mills using back calculation techniques. The liberation/breakage parameters were then used to simulate mill liberation performance under varying conditions.

Jan 1, 1996

By J. Wyn Prior

The seismic refraction technique is probably the most popular geophysical method of bedrock profiling in geotechnical site investigations but is somewhat restricted by the inherent assumptions in the method. This paper describes how Hales' method of profile interpretation is modified to overcome the assumptions of increasing velocity and layer thickness with depth when only first arrival data is available. A further expansion of Hales' method enables presentation of refraction data in a form whereby bedrock features, such as changes in velocity, relief and dip in particular, are more readily recognized. Characteristic curves of the more common bedrock features are presented as an aid to bedrock feature recognition.

Jan 1, 1979

By Franz Deix, Bernd Braun

A sensitive portion of Section U 6/3 of the Vienna, Austria subway system required construction of two single-track tunnels under a telecommunications facility, where strict ground settlement limitations had been set. Local geology, hydrology, and site constraints led to the decision to use the New Austrian Tunneling Method (NATM) supplemented by compressed air and partial dewatering. In addition, ground freezing was used, as the tunnel would pass through alluvial layers beneath the facility, with a cover of as little as 1.5 m. Laboratory testing and two in situ test fields were used to collect frozen soil data so that the freezing scheme ensured minimal heaving magnitude.

Jan 1, 1987

By Norman F. Sweeney, H. John Hovland

Over one million yards of granite were excavated for the Helms Pumped Storage Project, including a large underground powerhouse complex. Site investigations and in situ stress measurements were essential elements of the project design and provided the necessary geologic parameters for executing a finite element study of the powerhouse. A construction monitoring program, of geologic mapping, field instrumentation, and rock mechanics testing was then designed and has been successfully implemented. This paper reports on the scope of this construction monitoring program and explicitly compares the measured deformations to those predicted. As a result of this recent field experience the assumptions used in the finite element program are reexamined.

Jan 1, 1981

By Jerry W. Danni, R. Craig Ford, Kermit C. Benke, Jim B. Finley, Donald D. Runnells

Steady-state water balance models have historically been used in the management of acid drainage at mine sites. Such systems could be more realistically described by non-steady-state conditions. In addition, the evaluation of alternatives for closure and management of acid drainage must consider non-steady-state conditions. Dynamic systems modeling is a method for simulating water management systems, offering flexibility in: (1) simulating either steady-state or non-steady-state conditions, (2) allowing "what-if' scenario testing. and (3) optimization of operation and closure alternatives. A case study is given for acidic drainage management during closure at a heap leach facility that demonstrates the utility of dynamic systems models.

Jan 1, 2000

By S. Helgen, C. Byrns, A. Davis

The 4000 acre historic Robinson Mining District outside Ely, Nevada hosts a continuum of oxidelsulfide waste rock dumps of different ages. In an effort to develop a paradigm to explain past, existing, and future conditions at the site profiles of oxygen, pH, temperature, and specific conductivity were collected from various waste rock dumps using a hand-driven soil gas probe and a down-hole sampling device. The resulting data are useful in interpreting the fate and manner of pyrite oxidation within the dumps and in identifying waste rock dumps that may require remedial measures compared to those that require only minimal action prior to closure.

Jan 1, 2000

By T. Malterer, R. Adams

Peat has unique physical, chemical and biological properties. These include high porosity and water retention, high absorption and adsorption properties, and high buffering capacity. In addition, peat is a rich medium for microorganism activity. Peat has traditionally been used for horticultural purposes. However, in recent years, peat is increasingly being used for waste- treatment purposes. This paper reviews North American literature on the use of peat for waste-treatment applications. The literature indicated that peat has potential for use in the treatment of municipal and on-site effluents, for the removal of low concentrations of heavy metals and for the adsorption of liquid and gaseous hydrocarbon pollutants.

Jan 1, 1997

By G. R. Struble, J. R. Marks, A. B. Brown

The center of mining at the Homestake gold mine in Lead, SD, is moving deeper every year. As a result, it has become necessary to upgrade the ventilation system. This paper describes the first phase of a scheduled two-phase upgrade - installation of a 2.2-MW (3000-hp) centrifugal fan. The higher pressure fan is required to route larger airflows into the deeper production levels. Selection of the fan began by specifying the necessary operating point to provide these larger airflows. Special site work had to be done on the surface to accommodate the new fan structure as well as underground to reroute airflows.

Jan 1, 1987