# Relationship history for MSHA mine 3607686

Current hierarchy: **Kovalchick Peter → Peter Kovalchick Enterprises Inc → Buck Strip**

- 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:** K & M Coal Company → Buck Strip; 1985-05-01 to 1986-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Kovalchick Peter C & George Mazur → Buck Strip; 1985-05-01 to 1986-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Kovalchick Peter C & George Mazur → K & M Coal Company; 1985-05-01 to 1986-06-22; source msha-controller-operator-history
- **operator_operates_mine:** Peter Kovalchick Enterprises Inc → Buck Strip; 1986-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kovalchick Peter → Buck Strip; 1986-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kovalchick Peter → Peter Kovalchick Enterprises Inc; 1986-06-23 to current/open; source msha-controller-operator-history