The story about the Top Hammer XL system

Jarno Viitaniemi, Fredrik Björk and Jukka Siltanen from the Top Hammer XL team at Sandvik.

Optimizing drilling operations and cutting costs is a constant focus of surface mining companies. Sandvik now has a powerful solution for this: Top Hammer XL. This new concept expands the hole size range of top hammer drilling up to 178 millimeters (7ʺ). The Top Hammer XL system makes your drilling procedure fuel efficient and challenges the DTH drilling with the opportunity to drill much larger scale holes than before.

The system comprises a new drill rig, new rock drill, and new rock tools designed to work seamlessly together for optimum drilling performance and cost-effective results.
- The new rock drill, designed especially for the Top Hammer XL system, tackles the challenge of increasing the percussive energy of drilling action without increasing the drill's physical size. The innovative design results in improved drilling dynamics, where the rock drill is optimized for the rock tools and the target larger optimum hole size of 165 mm, explains Jukka Siltanen, Product Line Manager, BU Rock Drills at Sandvik.

When developing the Top Hammer XL system, the challenge was clear. Sandvik wanted to achieve a maximal penetration rate with minimal energy losses.
- With the Top Hammer XL system, we have more energy in the whole system, says Fredrik Björk, Product Manager Rock Tools Surface Drilling at Sandvik. The challenge was mainly solved by improving the drilling dynamics, which in turn requires careful balancing of several potentially conflicting parameters. One of these is the stiffness of the drill string to achieve straight holes, while at the same time avoiding excessive stiffness to prevent breaking of the tools under bending. This also means avoiding too large rod diameters because that will result in higher stresses in the thread joints under bending. Another key balance is between wear resistance and hardness because excessively hard tool steel will also be too brittle. A major asset for Sandvik in this respect is the steel grade and heat treatment expertise available in-house at Sandviken, Sweden.

Jarno Viitaniemi, Product Manager Surface Drilling in Sandvik continues.
- Sandvik has a long track record - over 50 years - with proven performance in top hammer drilling. Therefore, when it comes to the drill rig, it was natural for us to upgrade the existing, well-known platform to the next level for this new solution. I believe the carrier serves a good match for the new rock drill and tools - as matter of fact, the end-results are already proving to be quite self-explanatory.

The system has gone through extensive in-house bench testing and more than 100,000 meters of real-life drilling in challenging rock conditions. The results show a 50% reduction in fuel consumption, 25% reduction in total drilling costs, and 15% increase in productivity compared to the DTH drilling method.