DTH is short for “down-the-hole”. Since the DTH method was originally developed to drill large-diameter holes downwards in surface-drilling applications, its name originated from the fact that the percussion mechanism followed the bit down into the hole. Applications were later found for the DTH method underground, where the direction of drilling is generally upwards instead of downwards.
[pdf] Federal and state authorities are investigating the cause of the deadly explosion and fire at a natural gas drilling rig in southeastern Oklahoma on Monday. Five workers died in what appears to be one of the country’s deadliest onshore drilling accidents.
[pdf] The bodies of five workers, including one Texan, were recovered Tuesday after an explosion ripped through a drilling rig in Oklahoma, triggering what appears to be the nation's deadliest oil and gas accident since the 2010 Deepwater Horizon disaster in the Gulf of Mexico.
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