September 2012. From Engineering and Mining Journal.

Rockmore International’s 5-in.-range ROK 500DH hammer, the newest entry in its Deep Hole series, is intended to drill 5.5 to 6-in. (140 to 152mm) diameter holes and designed to increase drilling effectiveness and efficiency in deep hole applications that may exceed 1,000 ft. (300m) in depth and include high volumes of water.

Read the full article.