# Relationship history for MSHA mine 0401140

Current hierarchy: **Dennis N  Clarke → American Perlite Company → FISH SPRINGS 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:** American Perlite Company → FISH SPRINGS QUARRY; 1950-01-01 to 2019-09-08; source msha-controller-operator-history
- **controller_controls_mine:** American Perlite Corp Of California → FISH SPRINGS QUARRY; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** American Perlite Corp Of California → American Perlite Company; 1950-01-01 to 2019-09-08; source msha-controller-operator-history
- **operator_operates_mine:** American Perlite Company → FISH SPRINGS QUARRY; 2019-09-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dennis N  Clarke → FISH SPRINGS QUARRY; 2019-09-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dennis N  Clarke → American Perlite Company; 2019-09-09 to current/open; source msha-controller-operator-history