# Relationship history for MSHA mine 0403828

Current hierarchy: **Dave C  Varabioff → Colorado Quartz Gold Corp → Colorado Quartz**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Colorado Minerals Unlimited → Colorado Quartz; 1950-01-01 to 1982-04-27; source msha-controller-operator-history
- **controller_controls_mine:** Colorado Minerals Unlimited → Colorado Quartz; 1950-01-01 to 1982-04-27; source msha-controller-operator-history
- **controller_controls_operator:** Colorado Minerals Unlimited → Colorado Minerals Unlimited; 1950-01-01 to 1982-04-27; source msha-controller-operator-history
- **controller_controls_mine:** John E  Newman et al → Colorado Quartz; 1980-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Western States Mining Company Inc → Colorado Quartz; 1982-04-28 to 1988-12-12; source msha-controller-operator-history
- **controller_controls_operator:** John E  Newman et al → Western States Mining Company Inc; 1982-04-28 to 1988-12-12; source msha-controller-operator-history
- **operator_operates_mine:** Colorado Quartz Gold Corp → Colorado Quartz; 1988-12-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Larry E  Lehto → Colorado Quartz; 1988-12-13 to 2009-03-03; source msha-controller-operator-history
- **controller_controls_operator:** Larry E  Lehto → Colorado Quartz Gold Corp; 1988-12-13 to 2009-03-03; source msha-controller-operator-history
- **controller_controls_mine:** Lance W  Barker → Colorado Quartz; 2009-03-04 to 2017-09-09; source msha-controller-operator-history
- **controller_controls_operator:** Lance W  Barker → Colorado Quartz Gold Corp; 2009-03-04 to 2017-09-09; source msha-controller-operator-history
- **controller_controls_mine:** Dave C  Varabioff → Colorado Quartz; 2017-09-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dave C  Varabioff → Colorado Quartz Gold Corp; 2017-09-10 to current/open; source msha-controller-operator-history