Maybee, BM, Hall, S & Tousignant, A 2010, 'Evaluating the benefits of paste fill using advanced schedule optimisation techniques', in R Jewell & AB Fourie (eds), Paste 2010: Proceedings of the Thirteenth International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 175-183, https://doi.org/10.36487/ACG_rep/1063_15_Maybee
(https://papers.acg.uwa.edu.au/p/1063_15_Maybee/)
Abstract: Operational decisions within the underground mining industry have the ability to offer substantial increases 
in value if they can be made early in the project planning stage. The choice of fill technology is one of these 
operational decisions that have the potential to add significant value to the project. However, due to the 
manually intensive requirements to schedule the operations under multiple designs to allow for the 
comparison of the different technologies, the benefits are usually undervalued.  
In many cases, the benefits from a change in fill technology are limited to an evaluation of the sensitivity of 
the design to changes based on a modification in fill rate and curing times. What is generally not taken into 
account, due to time constraints, is that a change in fill technology may also allow for introduction of a 
completely new mining sequence. This might require a different equipment fleet and a completely different 
schedule, which may dramatically enhance the value of the project. These are not mutually exclusive 
decisions, and if a proper evaluation of the fill technology is to be undertaken, then all of the potential 
benefits and pitfalls must be included as the competing scenarios are evaluated for potential implementation. 
The Schedule optimisation tool (SOT) developed at MIRARCO uses advanced technology and computing 
power to identify and evaluate thousands of sequences and scheduling alternatives in a relatively short 
period of time. Through its optimisation process, SOT uses a powerful genetic algorithm to create multiple 
sequences of increasing value as it completely re-orders the activity set to find better sequences and 
schedules for the given design. Alternate designs can be considered in the same manner and new research is 
underway to develop rapid evaluation of multiple design options. As a result, a full scenario evaluation is 
possible, accounting for the fact that an improved mining sequence and equipment fleet utilisation may exist 
for a given change in fill technology.  
This paper describes how SOT can be used to identify the true scheduling benefits (as measured by net 
present value) that can be realised by a mining project through the use of paste fill. Through the use of case 
study data, it is demonstrated that the value of the mine can be substantially increased if all of the decision 
variables, both timing and operational efficiencies, related to that choice are accounted for in the 
evaluation.