GMR Year-In-Review: August 2025

The mining industry faces continual challenges in achieving operational efficiency, reducing downtime, and minimising equipment failure during drilling operations. One of the critical components in down-the-hole (DTH) drilling is the hammer, which undergoes severe mechanical stress and wear due to abrasive geological formations and high-impact forces. To address these issues, Robit Plc developed the H Series Marathon hammer – an advanced, high-performance line of rock drilling tools engineered for extended durability and operational lifespan.

The name ‘Marathon’ is emblematic of the tool’s core design philosophy: endurance and resilience under extreme operating conditions. This product line aims to extend maintenance intervals and reduce consumable turnover, particularly in mining operations where tool wear significantly impacts drilling economics. The introduction of the H Series Marathon represents a response to a prevalent demand in mining for drilling tools that sustain performance over prolonged intervals without compromising penetration rates or structural integrity.

Technical innovation

Drivers behind development

The conceptualisation of the H Series Marathon was primarily driven by the objective to mitigate excessive wear in specific high-stress hammer components – most notably, the drive chuck and wear sleeve. These components traditionally act as the primary points of end-of-life failure in DTH hammer assemblies, especially under continuous drilling in highly abrasive environments. Mining operations, which often entail prolonged, fast paced drilling in hard rock formations, amplify the wear rate of these parts, leading to increased equipment replacement frequency and associated costs.

The technical strategy centred on extending the operational threshold of the hammer by incorporating advanced metallurgical solutions and precision surface engineering. In particular, the introduction of plasma-transferred arc (PTA) coating technology on the drive chuck and a special heat treatment and material on the wear sleeve emerged as a critical innovation. These methods significantly increase surface hardness and resistance to erosion, thereby slowing the hammer’s degradation process during repetitive percussive and rotational motions.

Enhanced component design

The H Series Marathon hammers incorporate a reengineered drive chuck and wear sleeve with optimised geometric and material profiles to promote even wear distribution and improved stress tolerance. By reducing wear concentrations on isolated points, the new design mitigates premature failure and extends the functional period of these components. Structural enhancements also allow the hammer to maintain performance integrity closer to the nominal design discard limit, which is typically based on external diameter wear thresholds.

Test data supports that the total wear life improvement of H Series Marathon hammers ranges from 15 – 67%, depending on geological conditions and tool configuration. These improvements are particularly relevant for mining contractors aiming to reduce downtime caused by tool replacement, spare parts consumption and to enhance total meterage per hammer.

Thank you for enjoying this abridged article. Read the article in full and much more from the August 2025 issue of Global Mining Review here: https://bit.ly/4flScE9

Read the article online at: https://www.globalminingreview.com/mining/31122025/gmr-year-in-review-august-2025/