Pioneering maths has Big Mining’s support

By John Satterley

Thats the good word from Adelaide-based Emeritus Professor David Lee who has spent the past decade applying mathematical network theory on ways to optimise the design of underground mines; places he terms underground cities where tens of millions of dollars can be spent.
Global mining company Newmont Asia Pacific has been a major supporter of his work, which has seen the development of software packages like DOT a decline optimisation tool.
More recently he has become involved in finding how mathematical theory can be applied to rail systems to help alleviate the infrastructure blockages such as those experienced in the Port of Newcastle.
An article about Prof Lee in the University of SA newspaper UniSA News prompted this interview to see if his work could help contract miners in particular. He gave the interview the day after he and a PhD student completed a study for a local mining company that analysed the case for using road trains underground to move the ore.
Prof Lee was pro vice chancellor of research at the university for five years before retiring to continue research as an emeritus professor. When I retired I thought network theory could be used to design mining operations in underground spaces but it had never been done before, he says.
Melbourne University had one of the best network research groups in the world so I linked in with them. We have now reached the stage where six of the top mining companies in the world are sponsoring our research.
Hopefully mining software suppliers Maptek, Datamine and Gijima, who are also sponsors, will market the sequence of mining software packages developed through the project, which is due to be reported on this year.
Prof Lee says:  If you have an underground deposit, we have software now in this (research) group, that will design the stopes, design the access to the stopes and schedule the mine for maximum value.
The decline design tool is not restricted to single paths. We can now handle branching or tree networks. We are working with people who specialise in optimal stope layout. Another group is working on optimising mine scheduling.
Network theory stands back from the detail of the underground construction and declares: this is really just a set of lines joining points underground.
Mathematicians have studied how to find things like the shortest path through the network or the best cycles through the network. Here we had to adapt network theory to handle key operational constraints such as gradient and turning circle restrictions.
You can have a poor decline design or a good one, and mathematics helps you find the good one. A mine is a long timescale project, so the question is where do you start and how do you progressively develop that mine for maximum value.
If your haulage costs are high because you have chosen a particular network then you have a suboptimal solution over the life of the mine. The best way of getting the ore out should be considered at the same time as you design the infrastructure.
Prof Lee says a number of mining companies are looking at using road trains underground. However, to do so the question must be asked: do you get more tonnes for your dollar using road trains or ordinary trucks? We have found that a key issue for a road train design is finding the best places for the passing lanes.
If your location is wrong you will have a road train frequently delayed because the passing lane is in a bad spot for the operating schedule. Road trains are very expensive and at the end of a shift if you have lost an hour your schedule or underground layout is costing you money.