# Relationship history for MSHA mine 2901773

Current hierarchy: **Shamrock Mining Resources → Shamrock Mining Resouces → Silver Monument**

- 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:** B & K Mining Corp → Silver Monument; 1979-01-01 to 1981-03-16; source msha-controller-operator-history
- **controller_controls_mine:** Woolsey Tomas → Silver Monument; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Woolsey Tomas → B & K Mining Corp; 1979-01-01 to 1981-03-16; source msha-controller-operator-history
- **operator_operates_mine:** Fmc Minerals Inc → Silver Monument; 1981-03-17 to 1981-06-17; source msha-controller-operator-history
- **controller_controls_mine:** First Mississippi Corp → Silver Monument; 1981-03-17 to 1981-06-17; source msha-controller-operator-history
- **controller_controls_operator:** First Mississippi Corp → Fmc Minerals Inc; 1981-03-17 to 1981-06-17; source msha-controller-operator-history
- **operator_operates_mine:** Shamrock Mining Resouces → Silver Monument; 1981-06-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Shamrock Mining Resources → Silver Monument; 1981-06-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shamrock Mining Resources → Shamrock Mining Resouces; 1981-06-18 to current/open; source msha-controller-operator-history