# Relationship history for MSHA mine 3200853

Current hierarchy: **Tom  Gilbertson → Tom Gilbertson & Sons → PS-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:** Tom  Gilbertson → PS-2; 2001-03-12 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tom Gilbertson & Sons → PS-2; 2009-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tom  Gilbertson → Tom Gilbertson & Sons; 2009-09-01 to current/open; source msha-controller-operator-history