It's a great system. This is what all quarries in our area do. As CB operators we share the frequencies and understand that it is necessary for Triaxle, loader and dispatchers to communicate properly for their businesses to operate. One big happy 11 meter family if you will.
Since this is the CB section of the forum I suggest using 10/11 meter radios with dual finals. 4 watts will not ever cut it, plain and simple. Fact: Too many man made sources of radio interference exist today for a 4 watt transmitter to be effective during the daylight hours.
A dual final radio will net 10-30 watts AM and run on a cigarette lighter plug. You can use one as a base station with a 15 amp 12 volt power supply. DO NOT worry about the legality. Nothing is enforced on 11 meters anymore. (Why folks beat the anti-export radio drum always baffles me and no, please, do not explain it to us again. Thank you )
This is your business; you want consistent communication abilities with your workers and customers. Again do not not waste your hard earned money and try to mess around with the 4 watt toy CB stuff. Also, invest in good 95% rated coax and good quality antennas. Sirio and Stryker make some good antennas.
This is a tried and proven performer in the industry:
http://www.amazon.com/Galaxy-DX-29HP-Dx-29hp/dp/B005C48614