# Relationship history for MSHA mine 4406443

Current hierarchy: **Akers Larry W → Ponderosa Coal Corp → Mine No 2**

- 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:** Akers Larry W → Mine No 2; 1987-12-14 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ponderosa Coal Corp → Mine No 2; 1988-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Akers Larry W → Ponderosa Coal Corp; 1988-01-01 to current/open; source msha-controller-operator-history