# Relationship history for MSHA mine 0801096

Current hierarchy: **Morris E  Ridgdill → Ridgdill & Son Construction → Ridgdill & Son**

- 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:** Ashland Inc → Ridgdill & Son; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Apac-Florida Inc → Ridgdill & Son; 1988-04-01 to 1990-04-19; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc → Apac-Florida Inc; 1988-04-01 to 1990-04-19; source msha-controller-operator-history
- **operator_operates_mine:** Ridgdill & Son Construction → Ridgdill & Son; 1990-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Morris E  Ridgdill → Ridgdill & Son; 1990-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Morris E  Ridgdill → Ridgdill & Son Construction; 1990-04-20 to current/open; source msha-controller-operator-history