# Relationship history for MSHA mine 3402220

Current hierarchy: **David  Sherwood → Greenhill Sand → Greenhill Sand 1**

- 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:** David  Sherwood → Greenhill Sand 1; 2021-05-14 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Greenhill Sand → Greenhill Sand 1; 2022-01-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Sherwood → Greenhill Sand; 2022-01-26 to current/open; source msha-controller-operator-history