Yeah...has to be seismograph...or pretty close to it...

That roll of cable on the right of picture is what I used to carry 500ft (about 50lbs) of all day long in freezing snow, (when I encountered my case of frostbite on my fingers).

The grunt workers (which was me...lol), would carry the cable, hook em up to the seismograph for the operators to read. The machine vibrates electronic reading for ore. Once read, we unplugged the cables and move to the next area to be read, plug em back in. Repeat.
(I believe I have that correct, anyway...lol. It's been well over 30 years since I worked seismograph). Hard work, but GREAT pay.
Bummer was I was the only girl on the crew and those cables weighed half my weight....lmao.