# Relationship history for MSHA mine 1800543

Current hierarchy: **Wilhelm Gilbert → Wilhelm Coal Inc → No 1 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:** T & L Coal Company → No 1 Mine; 1974-07-01 to 1978-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Llewellyn Charles → No 1 Mine; 1974-07-01 to 1978-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Llewellyn Charles → T & L Coal Company; 1974-07-01 to 1978-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Wilhelm Gilbert → No 1 Mine; 1977-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Wilhelm Coal Inc → No 1 Mine; 1978-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wilhelm Gilbert → Wilhelm Coal Inc; 1978-12-01 to current/open; source msha-controller-operator-history