# Relationship history for MSHA mine 1700903

Current hierarchy: **Albert H  Blackstone Jr → A H Blackstone Jr. → A H Blackstone Jr.**

- 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:** A H Blackstone Jr. → A H Blackstone Jr.; 2012-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Albert H  Blackstone Jr → A H Blackstone Jr.; 2012-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Albert H  Blackstone Jr → A H Blackstone Jr.; 2012-11-05 to current/open; source msha-controller-operator-history