March/April 2011

Mapping the past reaps continual rewards

MineSight helps bridge the gap between 2D and 3D in Canada’s North

By Neville Judd

MineSight 3D software allows the user to digitize 2D data such as geological maps, drilling and surface data and convert it into a 3D model | Photo courtesy of Mintec Inc.

Picture the mess. Disintegrating paper data, rudimentary computer files close to obsolete – almost a century’s worth of valuable data from the historic Yellowknife Gold Camp on the verge of being lost or destroyed. This was one of the major challenges facing members of the EXTECH III multi-disciplinary project in Canada’s Northwest Territories. Its mandate was to develop new ideas and technologies to help mining companies find new reserves and deal with arsenic remediation issues.

EXTECH III began in 1997 as a collaboration of government scientists, private industry and seven Canadian universities. Among its priorities were bedrock mapping and geochronology, surficial mapping and geochemistry, geophysics, mineral deposit studies, and data integration and delivery.

The Yellowknife camp is one of Canada’s major historic gold mining districts. The two largest past producers in the camp, the Con and Giant mines, produced more than 5.5 million and 7.1 million ounces of gold, respectively. But weak gold prices, diminishing reserves and the mining companies’ wish to compare mineralization at Con and Giant led to EXTECH III. “It involved an incredible amount of work,” recalls Dean McDonald, former vice-president of exploration for Miramar, then owner of Yellowknife Gold Camp. “It was a project that some of us thought might be too ambitious.”

Building the 3D model

Much of the records from the two mining camps existed as old drill logs, plans, sections and sampling reports. This data needed to be compiled and integrated into a comprehensive three-dimensional geographic information system (GIS) model to provide a framework for both the study and remediation efforts. To accomplish this, EXTECH III used MineSight from Tucson, Arizona-based Mintec Inc., a software system designed to bridge the considerable gap between aging and archaic 2D data and a 3D model.

Garth Kirkham, of Vancouver-based Kirkham Geosystems, was responsible for integrating numerous decades and vintages of geological mapping and sampling, exploration drilling, surface data and mining into a 3D model.“The problem really came down to two factors,” says Kirkham. “All of the historic data, for this project and many other legacy mine sites, is 2D and exists as large volumes of paper or linens.”

“Multiple grid systems were used for various reasons and purposes,” he explains further. “This posed a problem, linking the datasets and the mines together in 3D now that the whole belt was under one umbrella for the first time.The first step was to digitize the data, which was laborious and time-consuming. Then this digitized data had to be placed and referenced in three dimensions.”

Using MineSight, Kirkham archived vast amounts of historical data and visualized the risk areas among arsenic stopes. Drill targets for future exploration were also identified. “The strength of the MineSight system is in its 3D modelling capabilities,” says Kirkham.“This allows the ‘linking’ of the 2D shapes into a 3D solid for visualization and for volumetric analysis. The result was an accurate representation of the mineralized structures along with a complete picture of the mine workings.”

Data mining

Surface features, surface geology, structural geology, current and historic mining areas, and point sample data (geochemistry and whole rock) are all now incorporated into the 3D GIS model. Also incorporated are production drilling and surface and underground explorations (including more than 60,000 drill holes). This has highlighted, in 3D, potential gaps in the drilling and areas with exploration potential. As well, geochemical point data derived from more than 5,000 analyses have also been incorporated and combined with the geostatistical models, allowing for useful visual display and analysis.

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