# Relationship history for MSHA mine 3605683

Current hierarchy: **Tueche Harry J → Laurel Ridge Coal Inc → Speyer Mine**

- 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:** Laurel Ridge Coal Inc → Speyer Mine; 1975-01-01 to 1984-11-11; source msha-controller-operator-history
- **controller_controls_mine:** Tueche Harry J → Speyer Mine; 1975-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tueche Harry J → Laurel Ridge Coal Inc; 1975-01-01 to 1984-11-11; source msha-controller-operator-history
- **operator_operates_mine:** Laurel Ridge Coal Inc → Speyer Mine; 1984-11-12 to 1986-07-14; source msha-controller-operator-history
- **controller_controls_mine:** Northbrook Metals Inc → Speyer Mine; 1984-11-12 to 1986-07-14; source msha-controller-operator-history
- **controller_controls_operator:** Northbrook Metals Inc → Laurel Ridge Coal Inc; 1984-11-12 to 1986-07-14; source msha-controller-operator-history
- **operator_operates_mine:** Laurel Ridge Coal Inc → Speyer Mine; 1986-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tueche Harry J → Laurel Ridge Coal Inc; 1986-07-15 to current/open; source msha-controller-operator-history