Dragline Excavation Sequencing

This project achieved an important step toward realizing 'live' excavation sequencing as a tool for real-time management of dragline excavation. The sequencing system guided excavation for a blocks pass operation, planning the operation sequence and having operators follow the guidance on repositioning the machine and on the material movement task for each tub position. The project focus was to advance the system implementation and foster the site engagement required to support a trial of the technology at a mine site in Queensland. A trial of guided operation on a final blocks pass scenario was successfully completed in November 2020. Operator interaction with the system and their performance under guidance provides optimism for the adoption of the operator assist into the dragline operation workflow.

The excavation sequencer is an operator assist technology that aims to regulate the dragline excavation process, thereby mitigating the risks associated with the status quo of distributed planning responsibility among all operators. The value of the system as a process controller is dependent on its capability to generate effective and efficient excavation tasks, and on the level of compliance and consistency achievable by operators. Compliance is an artefact of operator trust in the computed sequences and of the interface to which communicates the scheduled tasks; consistency emerges from a single on-board source for excavation scheduling. Productivity may then be regarded as an emergent property of the task schedule and the manner by which operators comply with the guidance.

The project built on the work of previous ACARP projects that developed the computational capabilities required for dragline excavation sequencing, including dig modelling, material spoiling, performance modelling, and a framework for formulating sequential decision making problems. Prior simulation studies, completed on different excavation scenarios, indicated productivity gains of 5-20% are possible with optimized sequencing of excavation tasks. The intent for this project was to have several trial instances and gather evidence throughout for a demonstrable impact on dragline operation. However, opportunities across 2020 were constrained and the production trial was limited to a single strip. The analysis presented in this report talks to the system development and deployment at the test site and addresses the quality of the computed guidance, the compliance to the operation plan, and the consistency of operation.

The project outcomes are described in detail in the final report.

The operation trial demonstrated that operators achieved a high level of compliance to plan and that providing a single reference for all operators supported consistency of operation. The trial strip offered limited margin for improving productivity, though the potential impact is well grounded by the mapping of effective guidance through compliance and consistency of operation to deliver productivity. The DES system will benefit from a broader level of trialling which should include a diversification of scenarios to which it is applied. The test site expressed strong interest in pursuing this testing, with the ambition to see the technology embedded in their workflow and ultimately supported as a product.