Geotechnical Design for Open Pit Coal Mining in Proximity to Electrical Power Lines: Risks, Mitigation, and Regulatory Compliance

Abstract

ABSTRACT: Open pit coal mining near electrical power lines presents distinct geotechnical challenges and regulatory demands, particularly under Section 17.6 of South Africa's Mine Health and Safety Act. This section requires a minimum 100 m buffer between mines and structures such as power lines unless deemed safe at closer distances. To balance safety with economic considerations, a detailed geotechnical risk assessment was performed to reduce this distance without compromising safety. This practical study is pivotal in optimising coal extraction while ensuring the integrity and safety of nearby power lines through well-considered geotechnical design. Employing empirical methods based on geological and geotechnical data, the study proposes a suitable geotechnical design, incorporating slope stability, ground control, and real-time monitoring to evaluate risks. This approach not only ensures compliance with regulatory standards but also enhances economic feasibility by increasing the minable coal resources. The findings highlight the critical role of comprehensive geotechnical design in allowing mining operations to coexist safely with essential power infrastructure. This research provides valuable insights for engineers, regulators, and industry stakeholders, establishing a framework for responsible mining in complex geotechnical environments. The recommendations from this study also guide future mining projects facing similar challenges, promoting sustainable and compliant mining practices. 1. INTRODUCTION The extraction of coal through open pit mining is a cornerstone of the global energy landscape, supplying an indispensable resource for power generation (Moloi and Zvarivadza, 2016; Woodworth, 2017; Pouresmaieli et al. 2023). However, when such mining operations occur in close proximity to electrical power lines, a unique set of geotechnical challenges emerges, requiring meticulous attention to safety, regulatory compliance, and economic feasibility. This paper delves into the intricate interplay of these factors, focusing on the geotechnical design considerations that underpin the successful and responsible extraction of coal resources in challenging geological settings near critical power infrastructure. The slope stability evaluation and design in this study pertain to an open pit mining project in close proximity to power lines. The objective is to find appropriate slope parameters such that the mine is stable, and the pit edge is not close enough to the power lines to cause the instability of the powerlines. This is in fulfilment of the Mine Health and Safety Act requirements as stipulated below: