Aerial and ground survey for efficient mine development

Aerial and ground survey for efficient mine development

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Geospatial technology plays a very critical role from aiding mining exploration to monitoring mines. A Malaysian mining company is using g-tech in the crucial development phases of the mine

The development of a mine site requires numerous layers of spatial data. Typically, companies utilise satellite data as a low cost broad-acre layer option and move to more accurate (and higher cost) layers as alternatives are refined and the decisions become more critical. While the temptation is to save costs and use existing or “under specified” data, the consequences of basing decisions on flawed spatial data can be dire.

A mining company in Malaysia combined aerial and ground survey techniques during the developing phases of the mine to increase accuracy. The mining company is currently conducting confirmation and exploration drilling and metallurgical test work on the deposits.

The project involved numerous components, all linked together to provide survey efficiencies. These components are detailed below:

»Survey control: Any field survey requires a sound network of reliable permanent survey marks (PSMs). In the early stages of exploration and development, little notice is given to the fundamental principal of “surveying from the whole to the part”. Exploration surveys often start at a single site and then expand to cover areas showing resource promise. This leads to poor survey geometry, and often no homogeneous survey network. This component involved AAM resurveying 15 PSMs across the site, with a Geospatial technology plays a very critical role from aiding mining exploration to monitoring mines. A Malaysian mining company is using g-tech in the crucial development phases of the mine mine development braced DGPS network adjustment.

»Data validation: As the mining company had recently acquired an interest in the project, there was a requirement to review and validate the existing survey data. This exercise is typical of such sites, where new owners are wary about investing further. The mining company was aware that survey shortcuts are often taken in the early stages of project development to save survey costs. Sound mining companies insist on basing significant investment decisions on known and reliable survey data and resource analysis. This component involved AAM resurveying existing drill hole collars to support a reliable review of the mineral resource.

»Validate claim corners: This required deploying licensed surveyors to confirm that the claim corners marked in the field did actually agree with the locations nominated on the certified plans. Often mining companies start developing areas outside of their mining lease due to erroneous (or displaced) field monuments.

»Previous LiDAR review: The mining company had existing LiDAR data which exhibited characteristics that it did not meet usual accuracy standards. This too is common as companies try to save costs by engaging survey companies not experienced in high-tech aerial surveys.

»New LiDAR survey: This required deploying a first order LiDAR sensor and experienced personnel to collect an accurate point cloud over the project area. Data points were collected at a point spacing of better than 1m, to accurately define the terrain surface across the site. The LiDAR sensor was able to define the terrain, even under dense Malaysian vegetation. This vital data layer serves many purposes over the life of the mine, including:

  • Accurate terrain surface to better assess the extent of the resource.
  • Detailed terrain surface to access the resource and plan stripping operations to quantify development costs.
  • Terrain definition to support planning of site infrastructure, such as access roads, plant sites and support buildings.
  • Hydrological studies, to support flood management of Malaysia’s tropical rainfall, and optimise dam sites for the mine’s ongoing operations.
  • Engineering studies to support design and maintenance of embankments.
  • Baseline archive of the site before operations, to record current landscape and protect mining company against any possible future claims of erroneous land disturbance.
  • Original surface definition, to support mine rehabilitation plans at the end of the mine site’s life.
  • Canopy definitions, to archive the height and extent of site vegetation prior to development.

»LiDAR spatial products: The LiDAR sensor defines the terrain shape, even under vegetation. There are a number of spatial products which can be extracted from the LiDAR data, including contours, cross sections, earthwork volumes, watershed boundaries and water flow models.

»Colour aerial photos: The mining company l also received 20cm digital colour orthophotos of the site. This accurate pictorial record complements the spatial definition provided by the LiDAR. The field survey team established ground control points (GCPs) while on site, to tightly orient the aerial photographs to the ground. These photos also combine with the terrain data to provide 3D visualisations and flythroughs across the site. These data products are useful for community consultation, investor summaries and help site planners visualise the site.