# Relationship history for MSHA mine 3607157

Current hierarchy: **Stiffler Albert F & Albert L → Pine Flats Coal Company Inc → Rockwell 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:** Stiffler Albert F & Albert L → Rockwell Mine; 1978-05-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Isers Run Coal Company Inc → Rockwell Mine; 1981-06-01 to 1987-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Mowry W Thomas → Rockwell Mine; 1981-06-01 to 1987-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Mowry W Thomas → Isers Run Coal Company Inc; 1981-06-01 to 1987-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Pine Flats Coal Company Inc → Rockwell Mine; 1987-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stiffler Albert F & Albert L → Pine Flats Coal Company Inc; 1987-09-01 to current/open; source msha-controller-operator-history