# Relationship history for MSHA mine 4406291

Current hierarchy: **Rose Avery → Graceco Energy Inc → No 1 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

- **operator_operates_mine:** Sherbett Energy Corp → No 1 Mine; 1986-04-01 to 1987-08-30; source msha-controller-operator-history
- **controller_controls_mine:** Delford B  Endicott et al → No 1 Mine; 1986-04-01 to 1987-08-30; source msha-controller-operator-history
- **controller_controls_operator:** Delford B  Endicott et al → Sherbett Energy Corp; 1986-04-01 to 1987-08-30; source msha-controller-operator-history
- **operator_operates_mine:** Graceco Energy Inc → No 1 Mine; 1987-08-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rose Avery → No 1 Mine; 1987-08-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rose Avery → Graceco Energy Inc; 1987-08-31 to current/open; source msha-controller-operator-history