# Relationship history for MSHA mine 3606601

Current hierarchy: **Helfer Ronald & Gary → Loyal Creek Coal Company → Graff Strip**

- 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:** Helfer Ronald & Gary Et Al → Graff Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Loyal Creek Coal Company → Graff Strip; 1978-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Helfer Ronald & Gary Et Al → Loyal Creek Coal Company; 1978-02-01 to current/open; source msha-controller-operator-history