# Relationship history for MSHA mine 1516778

Current hierarchy: **Shell Oil Company → Ratliff Elkhorn Coal Company → No 3 Surface**

- 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:** Meade Dale → No 3 Surface; 1981-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Shell Oil Company → No 3 Surface; 1987-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Big D Excavating Inc → No 3 Surface; 1989-11-01 to 1990-04-11; source msha-controller-operator-history
- **controller_controls_operator:** Meade Dale → Big D Excavating Inc; 1989-11-01 to 1990-04-11; source msha-controller-operator-history
- **operator_operates_mine:** Ratliff Elkhorn Coal Company → No 3 Surface; 1990-04-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shell Oil Company → Ratliff Elkhorn Coal Company; 1990-04-12 to current/open; source msha-controller-operator-history