# Relationship history for MSHA mine 3606338

Current hierarchy: **Bracken Laverne → Bracken Construction Company → Campbell Strip**

- 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:** Bracken Laverne → Campbell Strip; 1974-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bracken Construction Company → Campbell Strip; 1977-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bracken Laverne → Bracken Construction Company; 1977-02-01 to current/open; source msha-controller-operator-history