# Relationship history for MSHA mine 3606668

Current hierarchy: **Armitage Edwin B & C A Mc Dermott → M & C Coal Company → M And C Strips**

- 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

- **controller_controls_mine:** Armitage Edwin B & C A Mc Dermott → M And C Strips; 1975-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** M & C Coal Company → M And C Strips; 1978-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Armitage Edwin B & C A Mc Dermott → M & C Coal Company; 1978-05-01 to current/open; source msha-controller-operator-history