Welcome to the inaugural issue of the RGC e-newsletter!

On behalf of Robertson GeoConsultants I would like to invite our previous clients, associates, and new visitors to browse this newsletter to see "What's New"   at RGC.

Our objective in launching the RGC newsletter is to keep our clients and associates informed of some of the RGC activities and developments of interest. Through the newsletter we seek to inform you of some of the technical developments and capabilities that the staff of RGC are involved in or have completed.

As you are aware RGC maintains a high level of technology transfer through the development of technical tools, techniques and procedures that we make available to the mining industry through our web site as well as technology sites such as www.EnviroMine.com, www.HydroMine.com, and www.GeotechMine.com, as well as in courses and tools provided on the www.InfoMine.com site. This newsletter will also keep you up-to-date on these technical developments.

Happy reading,

Andy Robertson , President
Robertson GeoConsultants Inc.

Woodcutters Mine

Northern Territory, Australia

The Newmont Woodcutters  Mine Site is located 80km south of Darwin, Northern Territory, Australia. Between 1985 and 1998, the Woodcutters mine exploited a large lead-zinc deposit using open pit and underground mining techniques. In 1999, Normandy (the previous owner) initiated decommissioning of the mine, including relocation of all (sulphidic) tailings into the open pit and reflooding of the back filled open pit. In November 2000, additional studies were commissioned to finalize the closure design for the waste rock and to further evaluate the post-closure impacts on the local groundwater resource.

Newmont (formerly Normandy) Woodcutters Pty Ltd. retained Robertson GeoConsultants Inc. to carry out a detailed hydrogeological investigation and, in association with O'Kane Consultants, to assist in the development of a closure design for the waste rock pile. A comprehensive drilling and monitoring well installation program was carried out and a groundwater monitoring program (water levels and water quality) was initiated. This field data were used to calibrate a 3D groundwater flow and transport model for the Woodcutters site. This model was then used to predict future recovery of the groundwater levels and to evaluate the impact of pit reflooding and various cover options for the waste rock dump on the local groundwater system.

Newmont Woodcutters Pty Ltd. is currently in negotiations with the local stakeholders to develop closure performance criteria and the eventual release of the site back to the original landowners. The calibrated groundwater flow and transport model will provide an important reference for tracking future closure performance. Robertson GeoConsultants Inc. is currently assisting Newmont Woodcutters Pty. Ltd. in routine monitoring on the site and recalibration of the model, as required.  more...

An Overview of Prediction and Control of Air Flow
in Acid-Generating Waste Rock Dumps

by:  Dr. C. Wels,  Dr. R. Lefebvre and  Dr. A. Robertson

Air movement and associated oxygen transport through waste rock dumps has the potential to significantly enhance the rate of oxidation of pyrite-bearing material.

While this is a desired outcome for most heap leach operations, airflow in waste rock storage facilities can result in significant increases in generation and acceleration of acid rock drainage.

Hence, a good understanding of internal airflow through waste rock dumps is required to control ARD and minimize any associated liability.  more...

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Sebastien Fortin, M.Sc., B.A.Sc.

Mr. Sebastien Fortin holds a B.A.Sc. in Geological Engineering and a M.Sc. in Mining Engineering. Sebastien has worked as an Intermediate GeoEnvironmental Engineer with Robertson GeoConsultants Inc. since early 2000 and is responsible for all aspects of field investigations including supervision of drilling/ well installation, hydraulic testing and data analysis.

Sebastien has extensive field experience ranging from exploration drilling, monitoring well installation, hydraulic testing to water quality sampling. He has been responsible for several hydrogeological site investigations in Canada, USA, Australia and Africa. He has also assisted in the development/ calibration of groundwater flow and solute transport models.

Sebastien has also been involved in several geotechnical projects in the USA and in Africa. He has been responsible for field investigation work including in situ & laboratory testing, sampling, instrumentation and monitoring. He also assisted in tailings dam stability assessment by modeling and in the development/ calibration of tailings consolidation models.

Sebastien's Publications and Proceedings:

Curriculum Vitae:

HydroMine

Editor:  Dr. C. Wels

HydroMine  is a technology website created to inform professionals and the interested public about surface water and groundwater issues and technologies related to mining. Sponsored by Robertson GeoConsultants and edited by Dr. Christoph Wels, the site is one of several technology sites hosted by the much larger Infomine website.

InfoMine is a leading provider, of mining information worldwide, delivering content both remotely and via its Portal Site and Business Center on the Internet.   more...

Physical and Geochemical Characterization of
Mine Rock Piles at the Questa mine, New Mexico

by:  Shaw, S.,  Wels, C.,  Robertson, A.  &   Lorinczi, G. (2002)

published in: Tailings and Mine Waste '02, proceedings of the Ninth International Conference on Tailings and Mine Waste, Fort Collins, Colorado, USA, 27-30 January 2002, pp. 447-458.

The Questa molybdenum mine is located in the Sangre de Cristo mountains in Taos County, northern New Mexico. Currently the mining operations consist of underground block caving, however between 1965 and 1983 lower grade molybdenum ore was recovered by open pit mining methods during which time over 300 million tonnes of waste rock were produced. A comprehensive physical and geochemical characterization of the mine rock piles has been carried out at the site over the last few years to evaluate the current conditions and predict the future conditions. This paper describes the results of a drilling program completed as part of a larger scale, site-wide characterization program.  more...

Assessment of Store-and-Release Cover for
Questa Tailings Facility, New Mexico

by:  Wels, C.,  Fortin, S.,  Loudon, S.  (2002)

published in: Tailings and Mine Waste '02, proceedings of the Ninth International Conference on Tailings and Mine Waste, Fort Collins, Colorado, USA, 27-30 January 2002, pp. 459-468.

A test plot study has been initiated to study the performance of a store-and-release cover consisting of alluvial soil over tailings proposed for final closure of a large tailings facility in New Mexico. The test plot study consists of two closed lysimeters covered with 0.23m (9”) and 0.60m (24”) of alluvial soil (silty gravel) over backfilled tailings and an instrumented deep in-situ tailings profile with a 0.28m (11”) alluvial cover with existing grass/ shrub vegetation. All test plots were instrumented with temperature/ suction sensors and moisture content sensors to monitor moisture movement in the cover/ tailings profile. The lysimeters are free-draining and outflow is collected and monitored continuously using a tipping bucket. The calibrated model should be used to predict cover performance for a range of climate conditions (e.g. wet year vs dry year) and cover design parameters (e.g. cover thickness).  more...

Search RGC Papers

Hydrogeology and Hydrology

The RGC Image Library contains thousands of mining related technical photographs from projects located around the world.

Several hundred photographs are available for viewing on the web site, categorized into several geotechnical themes.

This month we showcase Hydrogeology and Hydrology. Projects included the Faro Mine in the Yukon, the Questa Mine in New Mexico, and the Quecreek Mine in Pennsylvania.  more...

Soil Mechanics

by:   Dr. C. Wels   and   L. Findlater

Many practical applications of hydro(geo)logy such as soil cover design, waste rock hydrology and tailings consolidation require a good understanding of soil mechanics. For some of the more common problems in soil mechanics, we have created interactive "Soil Mechanics Tools" which provide a visual interface for parameter input and output.

The following Soil Mechanics Tools are currently available:

Mass - Volume Relationships

• Phase Relationships for Soils
• Conversion for Slurry Discharge

For help on how to use the Soil Mechanics Tools, please contact Christoph or Laura.

We also welcome any suggestions for new soil mechanics tools.

New Mexico Bureau of Geology and Mineral Resources

by E-mail,

January 29, 2003

"I am very grateful that you share your company's research publications in via the Web. Well done!"

Thanks and regards, John Sigda

--
J.M. Sigda
Geohydrologist
New Mexico Bureau of Geology and Mineral Resources