# Relationship history for MSHA mine 3607491

Current hierarchy: **Camm Harry → Blackwood Anthracite Inc → Blackwood Stripping**

- 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:** Camm Harry Et Al → Blackwood Stripping; 1982-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Blackwood Anthracite Inc → Blackwood Stripping; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Camm Harry Et Al → Blackwood Anthracite Inc; 1983-09-01 to current/open; source msha-controller-operator-history