# Relationship history for MSHA mine 0500012

Current hierarchy: **United States Lime & Minerals Inc → Colorado Lime Company → Monarch 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

- **operator_operates_mine:** C F & I Steel Corp → Monarch Quarry; 1950-01-01 to 1985-07-10; source msha-controller-operator-history
- **controller_controls_mine:** Crane Company → Monarch Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crane Company → C F & I Steel Corp; 1950-01-01 to 1985-07-10; source msha-controller-operator-history
- **controller_controls_mine:** Tusco Inc → Monarch Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Calco Inc → Monarch Quarry; 1985-07-11 to 1988-07-10; source msha-controller-operator-history
- **controller_controls_operator:** Tusco Inc → Calco Inc; 1985-07-11 to 1988-07-10; source msha-controller-operator-history
- **operator_operates_mine:** Lowry Contracting Inc → Monarch Quarry; 1988-07-11 to 1999-06-03; source msha-controller-operator-history
- **controller_controls_mine:** Fred  Lowry → Monarch Quarry; 1988-07-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fred  Lowry → Lowry Contracting Inc; 1988-07-11 to 1999-06-03; source msha-controller-operator-history
- **operator_operates_mine:** Colorado Lime Company → Monarch Quarry; 1999-06-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** United States Lime & Minerals Inc → Monarch Quarry; 1999-06-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** United States Lime & Minerals Inc → Colorado Lime Company; 1999-06-04 to current/open; source msha-controller-operator-history