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Caterpillar top hammer outperforms DTH rigs

Cat MD5150C top-hammer drill rig

Cat MD5150C top-hammer drill rig proves its performance in tough applications in the US

EVEN in granite-like conditions the new Caterpillar MD5150C top-hammer drill rig is said to outperform down-the-hole (DTH) rigs with its higher productivity and much lower fuel consumption – while achieving comparable hole straightness.

Caterpillar conducted blasthole drilling studies at two quarries and say the results showed that lower-cost and faster top-hammer drilling can achieve similar borehole alignment to down-the-hole drilling, even in tough rock types.


The key to this performance, says he company, is the ability of the Cat MD5150C top-hammer drill rig to use larger-diameter drill rods (68mm), which help keep the drill string straight – even when the power is applied at the top of the string rather than deep in the hole.

According to Caterpillar, the savings created by lower drill consumables costs, lower fuel costs, lower drill maintenance costs and much faster drilling rates are considerable.

Iron Mountain Quarry, located south of St. Louis, Missouri, reports that overall productivity with the Cat MD5150C is almost double that of a competitor’s DTH drill rig. This is achieved thanks to the powerful Cat HPR6832 hydraulic rock drill, the new carousel rod changer and the efficient Cat C11 engine.

Moreover, the cost per foot is said to be better too. At Iron Mountain, the MD5150C drills 140mm diameter holes to a depth of 21.33m using 68mm-diameter drill steel. The bit can last 335m to 366m, which is the same consumption rate as the previous DTH drill rig. However, fuel consumption is said to be much less than the competitor’s DTH rig, while the drill steel experiences less wear and longer life.

According to Matt Jacobs, Caterpillar drills commercial manager, similar results were seen in an earlier trial at a Tower Rock limestone quarry near St. Genevieve, Missouri. ‘That site has softer rock conditions and the MD5150C dramatically outpaced a competitor’s DTH drill rig,’ he said.

‘Austin Powder conducted a bore tracking test and the results showed a hole-deviation rate with the MD5150C top-hammer drill that was within the desired range. Tower Rock are very pleased with their higher production and lower operating cost – all while achieving similar hole straightness.’


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