# Relationship history for MSHA mine 1000601

Current hierarchy: **Donald J  Nelson → Nelson Sand & Gravel Company Inc → No 3 Pit**

- 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:** Western Construction Inc → No 3 Pit; 1950-01-01 to 1979-04-08; source msha-controller-operator-history
- **controller_controls_mine:** Donald J  Nelson → No 3 Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Richard J  Heaton → No 3 Pit; 1950-01-01 to 2024-09-09; source msha-controller-operator-history
- **controller_controls_operator:** Richard J  Heaton → Western Construction Inc; 1950-01-01 to 1979-04-08; source msha-controller-operator-history
- **operator_operates_mine:** Nelson Sand & Gravel Company Inc → No 3 Pit; 1979-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Donald J  Nelson → Nelson Sand & Gravel Company Inc; 1979-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steven C  Heaton → No 3 Pit; 2024-09-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steven C  Heaton → Western Construction Inc; 2024-09-10 to 1979-04-08; source msha-controller-operator-history