I am not close enough to Grand Junction to verify this info:
Found this:
The Interagency Airtanker Base Directory lists the Grand Junction Tanker Base (at Grand Junction Regional Airport, GJT) as using:
Base Contact Frequency (Tanker Base Ramp): 123.975 MHz
(Also noted as the standard frequency for most airtanker bases in the Rocky Mountain region.)
Current (2025) frequency per PMS 507: 122.675 MHz (nationwide standard for airtanker bases)
Previously used standard (e.g., 123.975 MHz in some regions) has been phased out per FAA/NWCG directive