# Relationship history for MSHA mine 0800992

Current hierarchy: **Andrew R  Machata → Blackhawk Quarry Company Of Florida Inc → BLACKHAWK 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

- **operator_operates_mine:** Blackhawk Quarry Company Of Florida Inc → BLACKHAWK QUARRY; 1982-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Andrew R  Machata → BLACKHAWK QUARRY; 1982-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Andrew R  Machata → Blackhawk Quarry Company Of Florida Inc; 1982-11-01 to current/open; source msha-controller-operator-history