# Relationship history for MSHA mine 1506835

Current hierarchy: **Rag Aktiengesellschaft → Standard Sign & Signal Company → Frozen Dutch 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:** Appalachian Resources Inc → Frozen Dutch Mine; 1950-01-01 to 1974-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Standard Sign & Signal Co → Frozen Dutch Mine; 1973-01-01 to 1974-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Appalachian Resources Inc → Standard Sign & Signal Co; 1973-01-01 to 1974-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Standard Sign & Signal Company → Frozen Dutch Mine; 1974-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rag Aktiengesellschaft → Frozen Dutch Mine; 1974-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rag Aktiengesellschaft → Standard Sign & Signal Company; 1974-11-01 to current/open; source msha-controller-operator-history