# Relationship history for MSHA mine 1518220

Current hierarchy: **Meral  Williams → M & G Coal Sales Inc → Mine 1**

- 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:** M & G Coal Sales Inc → Mine 1; 1999-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Meral  Williams et al → Mine 1; 1999-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Meral  Williams et al → M & G Coal Sales Inc; 1999-11-01 to current/open; source msha-controller-operator-history