# Relationship history for MSHA mine 0202636

Current hierarchy: **Roy  Anderson → Roy Anderson Stone Company → BLUE BELLS 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Tom  Halquist et al → BLUE BELLS QUARRY; 1980-11-01 to 1999-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Apache Stone Company → BLUE BELLS QUARRY; 1995-05-01 to 1999-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Tom  Halquist et al → Apache Stone Company; 1995-05-01 to 1999-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Roy Anderson Stone Company → BLUE BELLS QUARRY; 1999-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Roy  Anderson → BLUE BELLS QUARRY; 1999-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roy  Anderson → Roy Anderson Stone Company; 1999-11-01 to current/open; source msha-controller-operator-history