Rock Will “Talk” To Device

Device

FROM the United States: seismitron, designed to grv vance warning of the rocK: or bursts which are the No. li in tunnelling and mining, hass to the South Pacific.

Certain types of rock, often “popping rock,” tend to audible sounds under strain, seismitron has been evolve' enable the trained ears of n and geologists to hear the hii inaudible sounds occurring ii material before falls occur.

The instrument, which ws vented by Liberty Mutual Insu Co. safety engineers in Bostoir sists of a highly-sensitive geof an amplifier of special design magnetic and crystal earphon hand counter and a watch an used.

Heart of the dev ic e is geophone. It is a 11 in. sealed, stainless-steel, round cylinder containing synthetic « crystals which act as the piu The piezoelectric action of quartz converts microseismic j tions into a minute current: The pulses of this flow are to audible level in the earß by the seismitron amplifer.

The seismitron is placed drilled hole about 3 ft deen an observer listens to the g?

“talk” for a predetermined pe: normally about 15 minutes at) placement. Weighing only with its batteries, the instn is readily portable and it cost than £ASOO.

It is claimed that the seisir will do all the following i much more accurately and posi; than can any miner “soundiir back” with hammer, bar or • Aid in warning minei approaching hazards. • Listen to the otherwise audible sounds of trapped min • Test the effectiveness ofi bolts or other mining and tin ling ground supports—steel, ti brick, concrete, etc.—and tell if port is needed in any given an • Help to test the effectiv of scaling (barring-down) ai check haulage ways for ul “loose.” • Detect the presence of ui termites eating away the hea? the timbers.

R. B. M. Long Pty. Ltd., of : ney, will manufacture the ami under licence in Australia, the firm probably will also the extremely sensitive geoph t Father Prasad, SM, first F" born Indian priest, was ordain:: Suva in July by the Vicar-Apo of the Fijian Islands (Bishop T Foley).