# Relationship history for MSHA mine 1506795

Current hierarchy: **Nicholas  Saylor → F & D Coal Company Inc → No 3 Mine**

- 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:** Nicholas  Saylor et al → No 3 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Middleton Coal Company → No 3 Mine; 1973-09-18 to 1974-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Middleton Obie Jr → No 3 Mine; 1973-09-18 to 1974-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Middleton Obie Jr → Middleton Coal Company; 1973-09-18 to 1974-09-30; source msha-controller-operator-history
- **operator_operates_mine:** F & D Coal Company Inc → No 3 Mine; 1974-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nicholas  Saylor et al → F & D Coal Company Inc; 1974-10-01 to current/open; source msha-controller-operator-history