Simplifying Underwater Decking Blastholes

Mintech invented the gasbag, which revolutionised blasting techniques within Australia and Internationally. The Mintech gasbag reliably provides cost reductions, increases safety and assists with environmental compliance. However non-dewaterable blastholes, where gasbags cannot be used at depth underwater, have always posed a problem – until now.

Mintech has simplified the method for decking underwater in non-dewaterable blastholes. Mintech has developed the Aquadeck. The Aquadeck allows the design decking to be continued across the whole blast area regardless of blasthole water level conditions and blasthole dewatering pump availability.

What is the Aquadeck?

The Aquadeck is a pair of hinged shaped plates which are geometrically proportional to the diameter of the blasthole. The Aquadeck is weighted and then lowered down the blasthole usually by a blasthole depth measurement cord. This procedure is similar to positioning a gasbag in a dry hole.

At the required depth the trailing ‘locking’ cord is activated. This action transforms the Aquadeck into its unique geometrically stable shape and thus forms a decking platform within the blasthole. The locking cord is attached to the blasthole peg (similar to that required for the downline) for additional security. The measuring cord is retrieved by applying tension and breaking the severable tag attached to the Aquadeck – (similar to that of cord retrieval after locating a gasbag). About 0.5m of drill cutting or gravel is then placed on the Aquadeck for protection and integrity.

What are the Aquadeck benefits?

  • Totally non-hazardous
  • Lightweight, easy to handle
  • No storage, transport or handling restrictions
  • No aerosols or compressed air
  • The design loading can continue regardless of blasthole water levels and dewatering equipment
  • May be located in the blasthole at any depth underwater
  • Not affected by climate extremes
  • Is not restricted to wet blastholes
  • Can replace gasbags where a jagged blasthole wall is hazardous and problematic.

Using a varied installation method, the Aquadeck may be recovered and re-used e.g. when temporary access is required across drill patterns. Using a recoverable Aquadeck not only provides for blasthole protection but it minimises waste and reduces the potential for blasthole blockages.

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