Show BUREAU OF MINES criticised criticized editor salt lake mining review referring to paragraph under above caption on page 16 of your issue for march 15 your nevada correspondent intimates that it is quite qui impossible for drill bits to become red hot as described in the article in your issue of february 15 your correspondent will be interested to know that on the storm king job on the new york aqueduct where diamond drilling was done to locate e solid ground for the siphon shafts and tunnel the water suddenly stopped in the rods of a diamond drill and although the trained operator imme immediately diatel y shut off the drill when the rods were hoisted the diamond drill bit had become a molten mass mas s of metal and black diamonds which closely resembled slag 9 your correspondent will also be interested t to 0 know that in certain very high grade copper glance drill bit bl on 78 7 8 inch hollow hexagon steel drilling dry with jack hammer type machine has gotten so hot that they re a fused mass there are no figures of speech used uselin the above yours very truly r BURT T BREWST BREWSTER ER E M salt lake city utah march 15 1922 |