# Relationship history for MSHA mine 0404349

Current hierarchy: **Cimenteries Cbr Cementbedrijven → Calaveras Cement Company → Gray Rock Quarry**

- 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

- **controller_controls_mine:** Flintkote Company → Gray Rock Quarry; 1950-01-01 to 1980-04-06; source msha-controller-operator-history
- **operator_operates_mine:** Flintkote Cement Company → Gray Rock Quarry; 1979-10-01 to 1980-04-06; source msha-controller-operator-history
- **controller_controls_operator:** Flintkote Company → Flintkote Cement Company; 1979-10-01 to 1980-04-06; source msha-controller-operator-history
- **operator_operates_mine:** Calaveras Cement Company → Gray Rock Quarry; 1980-04-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cimenteries Cbr Cementbedrijven → Gray Rock Quarry; 1980-04-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cimenteries Cbr Cementbedrijven → Calaveras Cement Company; 1980-04-07 to current/open; source msha-controller-operator-history