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By Frank Rausche

Since the early 1980s, when the Road Construction Authority of Victoria authorized the dynamic proof testing of roughly 100 drilled shafts of 1.5 m diameter and typically 60 m length in Melbourne Australia, dynamic load testing has been applied worldwide for quality control of drilled shafts. Today, test capacities of 4000 tons or more are not unusual. On numerous occasions the authors have been involved in similar tests in the United States and test engineers from other countries have reported on experiences in many different countries. Without doubt, generating high test loads is most economically accomplished by dynamic load testing and this method is particularly well suited for testing piles founded in rock because of the rocks low energy dissipation. However, deep foundation professionals have on occasion expressed reservations about subjecting a drilled shaft to impact loadings fearing, for example, a degradation of the shaft ? rock interface properties or potential error sources due to uncertain concrete properties or shaft geometry. This paper will present numerous case studies, demonstrating the performance of rock socketed drilled shafts under dynamic loads. It will discuss the mechanics of the dynamic tests and the method of data interpretation, addressing the concerns stated above and investigating the limitations of the test method. The paper will formulate a set of recommendations for the design and execution of these tests.

Jan 1, 2006

By Garth Howlett

In 1998 the Matanuska-Susitna Borough formed the new port district at Point MacKenzie, known as Port MacKenzie, located directly across the Knik Arm from Anchorage. In 1991 PND Engineers Inc. (PND), working with the Matanuska-Susitna Borough manager and port director, envisioned a fill structure at Port MacKenzie with a 500-foot-long Open Cell? sheet-pile bulkhead face extending to EL -20 feet Mean Lower Low Water (MLLW) at the face. Now under operation the fill created 5.5 acres of tideland property using local materials for fill. The fill is protected from 2- to-3 foot-thick ice pans and 9 feet per second (fps) tidal currents by an envelope of armor rock. Construction required working in water with 30 to 40 feet of tidal variation. Construction required placement of frozen fill in water depths possibly exceeding 50 feet, creating real concerns about soil consolidation and long-term maintenance issues. A plan was prepared to consolidate the soils using Vibracompaction. Soil Density and consolidation were monitored during the work. In 2003 the port district and NPI, a wood chip export company, formalized an agreement to construct a deep water port facility at Port MacKenzie for cape-class bulk carriers. PND provided planning, studies, geotechnical investigation, design documents and construction inspection for a 500-foot-long trestle with a platform dockhead and dolphins providing 1,100 feet of dock face in EL -70 MLLW as shown in Figure 1. Design included installation of large-diameter spin-fin piles driven on a 2V:1H batter. Also included was a 300-ton tension test of smaller spin-fin piles.

Jan 1, 2006

By G. Avolio, M. Gilbert

INTRODUCTION The city of Alexandria, Egypt is located on the Mediterranean Sea at the northwestern edge of the Nile River delta. The city is approximately 26 km long and 3 km wide bounded by the sea to the north and Lake Maryut to the south. The Alexandria Project is split into 2 phases: phase one included designs to update two existing primary wastewater treatment plants, five pump stations and over 75 km of sewer pipe, 18 km o f which is tunneled, (1500mm to 2750mm ID pipe). Currently the pipeline and pump stations are under construction. Phase two of the project includes expanding both the capacity of the treatment plants and the limits of the collection system. Included in this system expansion is the 3.5 km long, 2250mm ID Central Zone Conveyance, which is the subject of this paper. The project is under the direction of The Alexandria General Organization for Sanitary Drainage (AGOSD). It is an USAID funded joint venture of two American firms, CH2M - Hill and Metcalf & Eddy who share equally the major portion of the work and two Egyptian firms, Engineering Consultants Group (ECG) and Wairth Associates who are also partners. The venture, which is both design and construction management, worked under the name Wastewater Consultants Group, WWCG. Michael Gilbert was Chief o f the Geotechnical Department and Project Engineer for the Central Zone Conveyance. Gennaro Avolio was Geotechnical Exploration Manager for the Alexandria Wastewater Project.

Jan 1, 1987

By L. C. St. Arnaud

"Open pit mines can produce large disturbances within regional hydrogeologic systems. The degree of disturbance and the consequences on the local environment depend on the size of the pit and on the physical setting of the mine. Comparisons and contrasts are presented for three Noranda base metal open pit mine sites.The Brunswick Mining and Smelting No 6 open pit has a surface area of 11 ha and a depth of 185 m. It is located within complexly deformed schists and meta-volcanic rocks. The massive sulphide and iron formations visible along the north and southwest walls of the pit generate acid drainage. Mining ceased in 1983, and the pit is presently being filled with waste rock and neutralized drainage water. Water balance calculations estimated a total fill up time of sixteen years. As the water level rises, leakage to groundwater could take place across a fault zone intersecting the pit.The Mattabi Mines F-Group pit has a surface area of approximately 3 ha and a depth of 50 m and is also set in meta-volcanic rocks and acid generating iron formations. Production at this site ceased in 1982, and the low pH pit water is neutralized and pumped into a nearby lake at least every five years. Major water inflows are from precipitation and groundwater. Groundwater mounds within adjacent high land surrounding the pit provide a natural hydraulic barrier to groundwater flow, except for the southeast side. As a consequence, the pit water elevation is being kept below the elevation of the nearby creek in which some of the pit water could drain.The Bell Copper open pit covers an area of 40 ha and is 270 m deep. With present ore reserves, the mine might be in operation until 1992. The geology around the pit consists of andesitic tufts, siltstones and shales, and the acid generation potential of the rock is relatively low. A recent hydrogeological study estimated fill up time by precipitation and groundwater to be in the order of 260 years.With increasingly more stringent requirements for mine closure, it is anticipated that more detailed hydrological and hydrogeological studies of open pits will be required to determine post-closure environmental impacts and the suitability of open pits for mine waste disposal."

Jan 1, 1990

By Martin Herrenknecht

Tunnel boring machine (TBM) development continues to take on not only larger diameters, but also more difficult ground conditions. Ground conditions consisting of unstable faces with water pressures up to 15 bar have required innovative design approaches. A systems approach has been required to produce tunneling machines that can safely excavate the tunnel in an efficient, cost-effective manner that stresses production and labor saving approaches. This article reviews the current design developments and present recent projects where these most recent principles have been applied. The world?s growing population and rapidly proceeding urbanization are boosting an enormous demand for new and high-capacity infrastructures to secure the mobility of goods and people. Densely populated areas face the challenge of providing efficient traffic infrastructure such as a modern public transport system. At the same time, the maintenance and modernization of supply and disposal structures for water, sewage, energy and communication are essential. Last but not least, are supra-regional transportation routes such as long distance water diversion schemes. All of these projects are as demanding and are characterized by a tight time schedule. In this context, the demand for efficient tunnels for traffic and utility lines is increasing, as new infrastructures often leads underground because of limited space above ground. Also, tunnels are the obvious choice to cross natural barriers like mountain ranges. To handle the complex and variable geological conditions and other constraints, such as low overburden, high water pressure or long tunnel drives while facing increasing demand of a quick completion of a project, mechanized tunneling sets standards regarding safety, profitability and environmental protection in traffic tunneling projects as well as in the trenchless construction of utility tunnels. Different machine types and working principles have been developed to master various geological and hydrogeological requirements. Continuous activity in research and development leads to constant improvement of the mechanized tunneling process.

Jan 1, 2008

By Tomás Gonzáles

El presente trabajo describe la metodología usada para evaluar las estrategias de las alternativas del planeamiento a largo plazo en la explotación del mineral y el lixiviable en la Mina Toquepala.

Aug 25, 2002

By Pedro De Quintana

El siguiente estudio se basa en un trabajo anteriormente desarrollado en las minas de Quiruvilca por la compañía Northern, donde se efectuó un control radiográfico a sus trabajadores, obteniendo como resultado la enfermedad de silicosis en dicha zona minera. Por ello, el presente trabajo señala la importancia de las políticas de desarrollo y prevención de dicha anomalía, a partir de la información de la organización médica de Higiene industrial y de los demás ingenieros a cargo. La silicosis se produce a través de la inhalación del polvo que contiene sílice libre ( partículas menores de 5 micras) aproximadamente. Así, la primera medida a tomar es la reducción de dicho polvo en el yacimiento minero, manteniendo un porcentaje establecido en dicho polvo menor doscientos millones de partículas por metro cúbico de aire). Sin embago, si hay una mayor particularidad del elemento, mayor será la toxicidad a la superficie donde se encuentra. La segunda medida estriba en la protección a los trabajadores del polvo a través del equipo adecuado. La tercera medida, implica suministrar ventilación adecuada y obtener de la que se disponga el mayor rendimiento posible. Finalmente, la corporacion minera debe estar conciente de las medidas y garantías del control de dichos polvos, así como del examen médico previo, cambios de colocación, control periódico y de una compensación por enfernmedad profesional.

Jul 20, 1956

Nautilus Minerals and Neptune Minerals are betting that the next great metals rush will take place more than 1,500 m (5,000 ft) below the sea. Nautilus is the first company to commercially explore the ocean floor for gold and copper seafloor massive sulfide (SMS) deposits. Its main focus is the Solwara 1 Project, a polymetallic copper, gold, zinc, silver deposit that is under 1,600 m (5,200 ft) of water off the coast of Papua New Guinea in the western Pacific Oceans? Rim of Fire. Nautilus Minerals, in a joint venture with Placer Dome (now Barrick Gold), began its exploration of what would become the Solwara 1 area in 2005 with side scan sonar and dredge sampling. The dredge and grab sampling confirmed the grade tenor of earlier sampling by scientific research programs. The 45 dredge samples aver-aged 10.8 percent copper, 3.7 percent zinc, 224 g/t (6.5 oz/st) silver and 13.7 g/t (0.4 oz/st) gold. Nautilus has since staked out more than 300,000 km2 (115,800 sq miles) of tenement licenses and exploration applications in the waters off Papua New Guinea, Fiji, New Zealand, Tonga and the Solomon Islands. That is an area about the same size of the United Kingdom. Interest in Nautilus and its projects has grown tremendously since its inception. The company is now listed on the Toronto Stock Exchange. It has raised more than $300 million and spent more than $23 million on exploration. The company has gained the backing of mining majors such as Teck Cominco, Epion, Anglo American and Barrick Gold. It is positioned to become an emerging producer in 2010. Teck Cominco recently agreed to exercise share purchase warrants to acquire three million additional common shares of Nautilus at a price of US$15 million. This will take Teck Cominco?s shareholding to approximately 7.2 percent of the issued shares. Teck Cominco will conduct and manage a ship-based exploration program that will run in addition to the exploration that was already planned for 2008.

Jan 1, 2008

By Se-joon Kim, Jong-hwa Chun

"‘Gas hydrate’ is the common term for a solid material formed from the combination of various gases as ‘guest’ and water as ‘host’. A series of large-scale scientific drilling and coring programmes conducted since 2000 revealed that natural gas hydrate exists in a wide variety of accumulations in the sediments. The scaled-up onshore and offshore field production tests during the last decade show that gas production technology will be realized to make gas production from gas hydrates viable in the future, recognizing its potentials as one of the future sustainable energy resources.The total produced gas was approximately 470 m3 by the hot water circulation method over 6 days of operation in the permafrost-associated Mallik 2002 project in the Mackenzie Delta of Canada. In the Mallik 2007-2008 project, the gas was successfully produced stably by the depressurization method for 6 days, up to 13,000 m3 cumulatively. The depressurization method applied in the Mallik test was shown to be an effective way to produce gas from gas hydrates. The Alaska field trial to inject mixed gas of CO2 and N2 to exchange CH4 in 2012 was successfully done for the first time to produce maximum 1,270 m3 per day. A remarkable achievement was made by Japan when it completed its first offshore production test in the Eastern Nankai Trough, producing approximately 120,000 m3 of methane by the depressurization method over 6 days in March 2013. The technical challenges and scientific uncertainties obtained from Nankai Trough production test provide Korea with more considerations as to the aspects of well completion, reservoir formation and seafloor stability, sand control, flow assurance, environmental monitoring, and etc., due to the different geological setting and geomechanical properties of the Ulleung Basin in Korea."

Sep 1, 2014

The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces.

By Jerry Gagnon, Matt Burr, Dave Evans, Timothy Ellis, Davies Kakengela, Abbas Mirza, Larry Webb, François Leclercq, Andrew Johnston

Lead-based alloys are the primary anodes used in electrowinning from sulphate-based aqueous systems. Lead anode technology has evolved over the years, migrating from pure lead and lead-antimonial alloys to the present day lead-calcium-tin alloys for copper electrowinning and lead-silver alloys for zinc electrowinning. It has also migrated from cast to rolled microstructures in search of improved mechanical properties and higher corrosion resistance. Although great strides have been made in the development of new alloys and production processes, the industry still has unresolved issues related to untimely corrosion which limits anode life and may lead to higher contaminant levels in the metal being produced. Lead anodes corrode because of the difference in the chemical/electrochemical potential across the microstructural features of an anode. Given a very high purity material, we find that the grain boundary areas corrode significantly faster than the rest of the grain. The desire to minimize grain boundary corrosion by a balance of alloying element selection and microstructural design allows the grain boundary area to be engineered. However, operational issues can lead to unexpected corrosion behaviours which we will discuss moving forward. The comments in this work, though directed toward copper electrowinning, can be extended to similar phenomena in other metals electrowon from sulphate media (i.e., zinc, nickel, cobalt, manganese). The lifecycle of electrowinning anodes is dependent upon electrowinning tankhouse operating conditions and maintenance of the anodes, including cleaning and straightening. This paper will focus on the operational aspects of maximizing the utilization of lead electrowinning anodes.

Jan 1, 2015

By A. D. Fowler, M. T. Anderson

A phenomenological model is presented that relates Pb-Zn mineralisation to proximal geopressure zones. Typically, geopressure zones (GPZ) consist of masses of undercompacted sediment encapsulated within impermeable shales and are characterised by high formation fluid pressures. Heat flow is perturbed in some GPZ on account of their insulating properties. Geothermal gradients as high as 150 degrees C/km have been observed over short distances in the sediments of the US coast of the Gulf of Mexico. Some modern geopressure zones are known to reach temperatures of 120-150 degrees C at depths of 2.5-3.5 km. It is demonstrated that the zones may act as proximal sources of hydrothermal fluids, thus explaining the high temperatures of mineralisation observed in the deposits, which are hosted in basins characterised by thick, rapidly deposited, shale-rich clastic sequences

Jan 1, 1991

By K L. Brown

In the Waiotapu geothermal area only Champagne Pool, 109 ng/L, and Waiotapu Geyser, 7.6 ng/L, have dissolved Au concentrations greater than 5 ng/L and most springs have concentrations less than 2 ng/L. When Au concentration data are combined with other physico-chemical data from each spring including; pH, reduced sulphur concentration and temperature, the degree of Au saturation can be calculated. All samples sites except Champagne Pool, Waiotapu Geyser and the Artists Palette are under-saturated with respect to Au(s) by 1 to 3 orders of magnitude. This indicates that adsorption or co-precipitation or both are important processes depositing Au beneath hot springs. Deposition of Au by adsorption or co-precipitation beneath hot springs implies that dissolved Au may not have to reach saturation concentrations for ore to deposit. This interpretation is supported by the presence of substantial Au as sub-microscopic components within sulphide minerals in ore deposits and indicates depositional efficiency beyond that possible through precipitation of Au(s).

Jan 1, 2004

Effect of pH and Chain Length on the Flotation Separation of Fluorite from its Synthetic Mixtures with Calcite and Dolomite with Imino-Bis-Methylene Phosphonic Acid

Sep 13, 2010

By S Sandover, D Glenister

Alcoa World Alumina Australia is committed to sustainability principles as a basis of business success into the future. In March 2001, Alcoa Inc chairman Alain Belda announced a set of far-reaching environmental goals for the corporation, with the challenge that they should be achieved in ways that enhance economic and social performance, while substantially reducing environmental impact. Application of Cleaner Production methods is seen as the key to achieving these joint objectives. In Australia Alcoa has launched a co-ordinated effort to accelerate our application of Cleaner Production principles to delivering cost-effective in-process solutions to environmental issues. Our Western Australian Operations are a signatory to the WA Cleaner Production Statement, through which we provide a Cleaner Production Plan to the State Government on a voluntary basis. This paper describes in general terms AlcoaÆs goals, achievements and directions in applying Cleaner Production to enhance business performance in the economic, environmental and social dimensions. Quantification of the benefits and tracking of progress in quantitative terms is a key challenge for the future

Jan 1, 2002

By C. F. Vos, J. D. Miller, J. C. Davidtz

Small replacements of C12-trithiocarbonate (C12-TTC) for dithiocarbonate (DTC)/dithiophosphate(DTP) in a reagent suite for the flotation of platinum group metals (PGM) have significantly improved the rejection of gangue. Coupled to this is an improvement in kinetics, grade and recovery of PGMs. In a pilot-plant trial, after a 5 mole per cent replacement of the current DTC/DTP collector combination by C12-TTC, large opaque bubbles were replaced by small clear ones. In addition, a similar flotation response was realized with one-third of the current depressant dosage. During a preliminary plant trial on underground UG2 ore, the initial rougher concentrates were characterized by higher PGM concentrate grades and this was in part due to improved chromite rejection. The concentrate produced from the TTC trial also exhibited a much finer particle size distribution. The overall circuit performance, which included secondary regrind and flotation, showed an increase in concentrate grade of approximately 44% while the tailings grade remained unchanged

Jan 1, 2006

By Nicolás Guevara Alvarado

Las energías renovables son aquellas que se producen de forma contínua,+ y cuya disponibilidad energética es mayor que las fuentes de energía convencional. Sin embargo, su utilización es escaza, así como el desarrollo de las fuentes de energía convencional. En ese sentido, el presente trabajo plantea medidas que incrementen estas fuentes de energía, las preserven y mejoren su relación con el medio ambiente a través del avance de energías alternativas como la éolica, solar, etc.

Apr 1, 2014

By Kieran Black

The immediate roof lithology at United Colliery is extremely variable and provides a challenge for the design of secondary support. Support design in recent longwall installation roads at the mine has been carried out using strata management techniques. These techniques allow a robust yet economical secondary roof support design to be achieved. Analysis of roof lithology and roof displacement during first pass driveage are used as a basis for the optimisation of the secondary support design prior to roadway widening. This paper will demonstrate the application of practical strata management techniques in the optimisation of secondary roof support in six installation roadways at United Colliery. The experience gained from the installation roadways for LWs 1 to 5 will be briefy discussed. The experience from LW 6 will be discussed in greater detail. The paper will describe the strata management system that was used, including mapping, borescoping and extensometry, as well as the development and application of a Trigger Action Response Plan (TARP).

Jan 1, 2007

By Bill York-Feirn

The Colorado Mine Safety & Training Program (MSTP), in late 2005, completed and began distributing two new training tools; one geared to underground coal mine foremen and the other to surface aggregate employees. Through strong partnerships with MSHA, Colorado Coal Mine Board of Examiners, Colorado Mining Association and the Colorado Rock Products Association, the MSTP continues to create innovative and interactive training tools for not only Colorado, but for the national mining community. "Although we shoot and produce these materials in Colorado, it's important to us to make sure they are useful nationally," said Bill York-Feirn, MS TP Manager. The interactive DVD program "Underground Mine Foreman Certification Study Guide (Coal)," was completed in October 2005. It won the 2005 Grand Prize at the MSHA National Training Materials Competition in Beaver, West Virginia. [ ] This program is fully based upon the requirements of Title 30 Code of Federal Regulations (30 CFR) Parts 48, 50, 70 and 75 for underground coal mine foremen. It contains eight modules plus immediate access to relevant laws in the appendix. Topics covered include: Federal Law, Practical Math Skills, Mine Gases, Ventilation Maps, and scenarios addressing a variety of practical mining concerns. The DVD is designed for self-¬paced study and practice.

Jan 1, 2006

By Matthias Rheinlander

The paper will describe Virtual Design and Construction (VDC) as a tool which will enable us to build a project ?virtually? on a computer before constructing and operating it in the real world. VDC computer models are built, using information from various sources including survey, 3D laser scanning, CAD and GIS to represent the project and its components in a coordinated and consolidated infrastructure model. This model is reviewed and evaluated by, and shared among project teams including owners, con-tractors, designers, engineers, construction managers, stakeholders and operators. It allows teams to fix costly design and construction issues before construction on site. Benefits and lessons learned from global projects will be discussed