2004

In 2004 Cementation carried out a detailed study for Falconbridge (now Xstrata Nickel) on “rapid development” based on a review of global tunneling practices in mining and civils projects with emphasis on obtaining reliable information on advance rates.

Projects considered notable for their advance rate achievements from recent times were reviewed while recognizing and adjusting for contributing factors affecting advance rates from the conditions prevailing in the industry historically at the time to the safety culture of the region. The study provided a comprehensive review of advance rates achievable with tunneling practices that had merit enough to be included in the study.

To assess the potential benefits for application in mining, these tunneling systems and cycles were incorporated into a project simulation to analyze interactions and delays that occur when advancing not just a linear heading cycle, but also for optimization of layouts as well as the systems and cycles.

2006

Building on the 2004 study, in 2006 a further “rapid development” study considered a number of options for the layout and development methodology of a 2.4km long access drift. Tunnels of various sizes were considered - using rubber-tire equipment, tracked equipment and rail-bound equipment, and a combination of these. Experienced international input was obtained with a brainstorming session covering a wide range of issues, and included representation from Norway, Sweden, South Africa and UK.

The study looked at achievable daily advance rates, overall time schedule, and overall costs. Cycle-times were determined by statistical analysis using actual time-study data of elements of work comprising the overall cycle from existing operations, supplemented with practical operational knowledge and experience.

Having carried out the theoretical assessments, a series of “bench-marking” studies against precedent case histories were undertaken in order to confirm and validate the outcomes. Anticipated risk factors associated with operating within an existing mine were also applied to establish overall advance rates.

The study provided a reasoned basis to decide which combination of options would be the most appropriate. Calculated relative costs and durations provided the data needed to carry out cost-benefit studies and forward into feasability and subsequent engineering. The preferred methodology made use of a combination of track and trackless equipment for drift construction. The selection of track haulage as the drift development methodology took into account that the ultimate use of the drift would incorporate track haulage for mining.