# Relationship history for MSHA mine 4201260

Current hierarchy: **Ford Gordon M → Delano Development Corp → Sulphurdale 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:** Delano Development Corp → Sulphurdale Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ford Gordon M → Sulphurdale Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ford Gordon M → Delano Development Corp; 1950-01-01 to current/open; source msha-controller-operator-history