# Relationship history for MSHA mine 4703139

Current hierarchy: **Tom  Halquist; Bill  Halquist → Halquist Stone Company Inc → Halquist Stone Company - Chilton Quarry**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Tom  Halquist et al → Halquist Stone Company - Chilton Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Chilton Stone Company → Halquist Stone Company - Chilton Quarry; 1998-05-01 to 2005-05-30; source msha-controller-operator-history
- **controller_controls_mine:** Bill  Halquist et al → Halquist Stone Company - Chilton Quarry; 1998-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Halquist et al → Chilton Stone Company; 1998-05-01 to 2005-05-30; source msha-controller-operator-history
- **controller_controls_operator:** Tom  Halquist et al → Chilton Stone Company; 1998-05-01 to 2005-05-30; source msha-controller-operator-history
- **operator_operates_mine:** Halquist Stone Company Inc → Halquist Stone Company - Chilton Quarry; 2005-05-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tom  Halquist et al → Halquist Stone Company Inc; 2005-05-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Halquist et al → Halquist Stone Company Inc; 2005-05-31 to current/open; source msha-controller-operator-history