rf Propagation in quarry

[kens]

I just received a call from a local quarrying operation about changing from their old CB radio system. The operation looks to be about 40acres with an open pit about 150' from top to bottom. They mine various types of rock for roadbuilding. The office they need to talk to is near the rim and they want coverage to the bottom of the mine. Since I have little experience in this type of operation, I thought I would ask here about possible problems before I try out radios. I was thinking vhf?
Thanks to all.
Ken

[Will]

Do they still use CB, 27 mHz? Some call everything CB. Maybe GMRS....

[Bill_G]

VHF would be fine for overall coverage, but electrical noise (fans, accessories, video screens, etc) inside the heavy equipment could clobber you. UHF will give decent coverage in the pit, but may not cover the entire property in simplex. You may find the occasional birdie in UHF from the LCD displays in the cab.

My experience with agg operators is they say they are broke, act like they are broke, and bemoan every nickle you charge them. If these guys are using CB now, expect them to ride you like a horse over price, and then never call you back. Lots of romance and no joy.

[Bigred]

The first TRBO system we ever sold was to quarry, bigger than the one you describe. It's VHF simplex and radios are in the heavy equipment and various offices around the site. Works like a charm, even out of the pit although there is a hill on the far side that may help with a bounce.

They got the new new radios to replace 900 Spectras that were dying on the vine. The reason was an accident that the Bureau of Mines determined was made more serious by poor communications and put the pinch on them to correct. With this in mind, I don't see how you can get away with CBs.

[MSS-Dave]

My experience with agg operators is they say they are broke, act like they are broke, and bemoan every nickle you charge them. If these guys are using CB now, expect them to ride you like a horse over price, and then never call you back. Lots of romance and no joy.

Seriously, like the last post, I would think this would be a perfect place to put TRBO digital. NO experience with a quarry but in a heavy industrial area and a power plant, a demo of digital TRBO versus analog 900 MHz system really opened my eyes. I can't answer whether any other digital format would work better or worse (NXDN, iDas, P25 FDMA, etc) though...

Dave