Construct New Residue Storage Area

Construct New Residue Storage Area

Category: Tailings Dam
Client: Major Mining Company
Project: Construct New Residue Storage Area
Project Value: $120 million
Timeframe: February 2012 – November 2014

Background

BE Surveys was appointed to the project, as a sub-contractor to the main civil contractor, to undertake the surveying and generate operational data for the construction of the 100 hectare tailings dam.

The project included:

  • Bulk Earthworks
  • Tri-Liner
  • Residue Sand Drainage Layer
  • Underdrainage – Collectors Draincoil
  • Sprinkler Laterals
  • Dust Suppression

Challenges

  • Due to the unavailability of suitable clay the area was lined with a composite tri-liner (Australia first) which consisted of three separate layers. This presented its own unique challenges with every panel, repair and destruction test of the HDPE liner having to be shown in an as-constructed survey drawing.
  • Ninety percent of the Residue Sand Drainage Layer was hauled from the stockpile in four month from April ). The high pace of haulage  made weekly volume reports of sand taken and sand added to the stockpile (sand was being hydraulically poured onto the stockpile at the same time as it was borrowed).
  • With 80Ha of residue sand on the dam floor, covering the dam floor with 750Ha of dust suppressing aggregate in 14 days was a major project achievement. Progress was tracked with regular survey reports.
  • Drainage Layer Design. Due to high areas in the tri-liner (cause by Manitou wheel ruts when installing the liner) we redesigned the dam floor to maintain the  sand drainage layer. It was important to maintain the design features of sand between the liner and the draincoiland  cover above the draincoil.
  • With such a massive amount of draincoil (75,670m) to be installed we simultaneously ran Trimble GPS and Total Station machine guidance systems to allow the dozers to directly rip the draincoil into the sand layer. This technique did not allow the surveyor to directly ascon the draincoil so the ascon was measured during installation using the dozers’ machine control system.
  • The 18,830m of sprinkler laterals were installed just 100mm above the draincoil. Extra care was needed not to damage the draincoil while trenching for the sprinkler system. To avoid hitting the draincoil we set out and potholed every location that the draincoil crossed the sprinkler trench.
  • Each week BE Surveys reported to the main civil contractor’s management in terms of areas, volumes and quantities handled in due course of project implementation.

In addition, throughout the duration of the project, BE Surveys demonstrated a flexible approach which ensured the project was delivered on time.

Residue Area 2  Residue Area 1

Outcomes

Considering the duration of the project as well as its complexity, BE Surveys demonstrated a professional attitude and excellent customer liaison skills which ensured the project stayed on track and within the required timeframe.

This project demonstrated BE Surveys expertise and sound knowledge of surveying and design which ensured the project was delivered on time and as per the scope of works.

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