Huang, Y 2009, 'The impact of an unexpected fault zone and groundwater in a ramp development on cost and production rate — a case study', in PM Dight (ed.), SRDM 2009: Proceedings of the First International Seminar on Safe and Rapid Development Mining, Australian Centre for Geomechanics, Perth, pp. 121-127, https://doi.org/10.36487/ACG_repo/902_11
(https://papers.acg.uwa.edu.au/p/902_11_Huang/)
Abstract: In mine development, cost per metre and production rate per shift are two of the most important criteria in 
terms of measuring economic results, work efficiency and technological advance. Therefore a key focus of 
engineering work in mine development is to reduce the cost and increase the production rate while meeting 
safety, environmental and production requirements. 
This paper presents a case study in which a ramp development encountered an unexpected fault zone. 
Because of the very fractured rock and high water conductivity in this zone, the cost per metre was sharply 
increased and the production rate per shift was dramatically reduced. This meant that a number of extra 
measures were required in order to efficiently advance through the fault zone. 
The water pressure encountered in many blastholes in the fault zone was more than 400 kPa and grouting 
was used in an attempt to control the water flow. In spite of this action the development drive back still 
collapsed, several further measures were required to rehabilitate the collapsed back and keep the 
development going. 
The nature of the fault zone, the grouting technology used, the rehabilitation measures for the collapsed 
drive back, the ground support policy adopted and the blasting techniques used in the fault zone are all 
discussed in this paper. 
The cost per metre and production rate per shift in going through the fault zone, compared with normal 
ground conditions, is estimated. 
This case study also provides a good example of the importance of obtaining detailed geotechnical data in 
advance, to facilitate correct location of mine development in good ground conditions.