Work practices involved in shaft construction can be aligned with current
industry standard operating practices. However, the working environment during
conventional shaft construction introduces unique conditions which can not
always be overcome by hard engineering controls. To provide an improved working
environment, future shaft diameters will generally be greater than has
historically been the case for the Australian hard rock mining industry.
This paper aims to explore both what can be constructed from the contractors perspective, and how does an owner extract maximum business efficiency from an asset that in many ways is likely to be larger, more complex and more expensive than initially envisaged.
Newcrest Mining Limited, or an associated company, has constructed two major shafts over the last seven years. In both cases, Byrnecut Mining, or an associated company, was the contractor engaged for the shaft sinking activity. The first is the 1127 m deep, 7.0 m diameter production and intake airway at the Telfer Gold Mine, the second is a 295 m deep, 5.5 m diameter split shaft at the Gosowong Gold Project in Indonesia that was primarily designed as both an intake and exhaust airway. Importantly both shafts are designed to provide emergency egress from the respective underground operations.
From an Australian shaft sinking perspective, the construction of these two shafts resulted in the following learnings:
•constructability is of equal importance to desired functionality;
•allow six months of interactive design between the owner/engineer/contractor/regulator to get it right;
•shaft sinking and equipping are intimately entwined, therefore engineering of both needs to be complete prior to any activity commencing; and
•the mobilisation of both equipment and experienced personnel to a new shaft sink takes up to eight months.
Shaft sinking is not extinct in the
Australian hard rock mining industry. But, if you are considering constructing a
shaft, approach it as a long life asset, front end planning to a high level of
detail is required to unlock its full value. Think – plan – think and remember
it’s going to take 12 months to get from the whiteboard to firing the first cut.
Kilkenny, D J and
Dennis, J M, 2011. Mine shafts
– planning, optimising and constructing, in Proceedings 11th AusIMM Underground Operators’
pp 115-126 (The Australasian Institute of Mining and