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This paper presents an economic model for optimizing loading at the draw point in sublevel caving (SLC) operations. The input data consist of estimated bucket grades based on bucket weights from Load Haul Dump machines. This information, together with average operational mining costs, was used to create an economic model providing a real-time economic assessment of the draw point performance for SLC rings. The results demonstrate the importance of continuous draw point monitoring to optimize SLC operations. The proposed model provides an economic assessment of operating draw points and will help mine personnel to decide when to stop loading from a blasted ring. It can also help mine management understand the complexity of material flow in SLC operations. Finally, it provides operational flexibility for the mine to optimize loading at the draw point by increasing ore recovery while maintaining operational control of draw point performance.

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This paper addresses the identification of the optimal draw control strategy for a sublevel caving (SLC) operation at Malmberget mine in Sweden. Two mathematical models, a probability model and an economic model, were created using five datasets: bucket weights, bucket grades, extraction ratio, mine economics parameters and production constraints. The probability model was used to generate a set of simulated bucket weights and corresponding bucket grades which acts as a 'virtual mine' environment. The economic model assesses the economic impact of loading at the draw point. Two approaches to draw control were tested using the 'virtual mine' created by the probability model. Based on the results of the simulation tests, an optimal draw control strategy is suggested for a field test at the mine. The new draw control strategy optimises further the loading operation at Malmberget mine. The paper shows a roadmap for optimising draw control strategy for SLC operations.

Orepasses are used in rock mass transportation systems to transport the material to lower levels. If the ability to transport the material is lost, the failed orepass can be restored, but the process is usually costly, and the time to restore the orepass is usually long, possibly resulting in disturbances in material flow. This study introduced a longevity chart to plan for the availability and renovation of orepasses. A longevity chart is based on the orepass parameters, such as geotechnical conditions, stress and strength regimes, design parameters, and operational procedures. It guides mine planners in the creation of future production plans and renovation plans for the orepasses. The study presented in this paper was based on the Luossavaara-Kiirunavaara Aktiebolag Kiirunavaara sublevel caving mine located in the northern part of Sweden. This paper explains the creation process of the longevity chart and its implementation in renovation plans.