Mancala's method of progressive shaft opening via raise boring and Horadiam techniques can be used in the excavation of new shafts and for construction of large underground coal bins.
Mancala's Horadiam method offers a significant increase in productivity compared to traditional sinking methods.
Construction can take place in relatively poor rock masses where large diameter raise boring would be considered high risk.The progressive shaft opening technique allows the inherent geotechnical risk in shaft construction to be effectively managed.At each stage of the shaft's construction the geotechnical characteristics of the rock mass can be assessed and appropriate ground support regimes can be installed.
Horadiam construction of large diameter shafts incorporate:
Minimised Risk
- Technical and commercial risk can be minimised via continuous assessment of the geotechnical environment.Permanent ground support can be installed beyond the shaft's final diameter prior to excavation.
Fast and Efficient
- At Lenstier where traditional raise boring methods failed, Mancala enlarged a 2.4m diameter shaft of 200m length to 5.5m in less than 9 weeks on site.
- The productivity, efficiency and flexibility of Horadiam place it as one of the most cost effective methods of shaft construction.
- The top down temporary support and Horadiam drilling followed by blasting from the bottom up ensures men are working at all times under fully inspected and supported ground.
- Shaft centre line accuracy of 0.01% of the shaft length can be achieved using a directionally drilled pilot hole.During refurbishment or enlargement shafts can effectively be straightened by varying the Horadiam blast hole lengths.
- Mancala has excavated over 3.0km of shafts up to 6.0m diameter using the Horadiam technique. Clients have opted for fibrecrete or concrete lining incorporating various water control devices.
