Autonomous Loading System for Load-Haul-Dump (LHD) Machines Used in Underground Mining

Abstract

This paper describes an autonomous loading system for load-haul-dump (LHD) machines used in underground mining. The loading of fragmented rocks from draw points is a complex task due to many factors including: bucket-rock interaction forces that are difficult to model, humidity that increases cohesion forces, and the possible presence of boulders. The proposed system is designed to integrate all the relevant tasks required for ore loading: rock pile identification, LHD positioning in front of the ore pile, charging and excavating into the ore pile, pull back and payload weighing. The system follows the shared autonomy paradigm: given that the loading process may not be completed autonomously in some cases, it takes into account that the machine/agent can detect this situation and ask a human operator for assistance. The most novel component of the proposed autonomous loading system is the excavation algorithm, and the disclosure of the results obtained from its application in a real underground production environment. The excavation method is based on the way that human operators excavate: while excavating, the bucket is tilted intermittently in order to penetrate the material, and the boom of the LHD is lifted on demand to prevent or correct wheel skidding. Wheel skidding is detected with a patented method that uses LIDAR-based odometry and internal measurements of the LHD. While a complete loading system was designed, the validation had to be divided in two stages. One stage included the rock pile identification and positioning, and the other included the charging, excavation, pull back, and weighting processes. The stage concerning the excavation algorithm was validated using full-scale experiments with a real-size LHD in an underground copper mine in the north of Chile, while the stage concerning the rock pile identification was later validated using real data. The tests showed that the excavation algorithm is able to load the material with an average of 90% bucket fill factor using between three and four attempts (professional human operators required between two and three loading attempts in this mine).

Haulage Cycles Identification for Wheeled Transport in Underground Mine Using Neural Networks

“…Both machines usually perform spoil transportation between the mining face and the grid. There are two configurations in which this kind of ore transportation can be performed with these types of machinery [ 24 ]; by using the loader either alone or accompanied by haul trucks. Work cycles for both machine types are presented in Table 1 .…”

Autonomous detection and loading of ore piles with load–haul–dump machines in Room & Pillar mines

“…Following Tampier et al (2021), the autonomous loading process is modeled inspired by the described way operators perform the loading procedure, and considers the following steps:…”

“…In Magnusson and Almqvist (2011), an actuated LIDAR is used for reconstructing the pile. Finally, in Tampier et al (2021) two 2D LIDARs are used. In all of the other works, only the machine's internal sensors are used.…”

“…In this work, Tampier et al (2021) are extended to be able to work on Room & Pillar mines, which involve wide tunnels, and where multiple ore piles with different slopes can be present. Then, several possible trajectories to attack the piles are possible, but only some of them are free of collisions with the walls and can be performed without damaging the LHD.…”

Dust pollution hazard and harmful airborne dust exposure assessment for remote LHD operator in underground lead–zinc ore mine open stope

“…It is well known that the operation of tele-remote LHD can be controlled from the surface control room, which facilitates the operator to operate the LHD at the earliest after shift allocation and runs the LHD till the end of 8-hour shift (Hwang et al, 1999). Future studies may consider full automation of LHD operation in a de ned layout in mines or sections of mines, which eliminates the physical presence of remote operators in mucking areas (Tampier et al, 2021). Moreover, mine ventilation is an integral part of dust control strategies to dilute the respirable dust in working areas in FMUMM (Cecala et al, 2005).…”