# Relationship history for MSHA mine 4201929

Current hierarchy: **Steve L  Gilbert → Gilbert Development Corp → GDC Crusher #2 - Portable**

- 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:** Steve L  Gilbert → GDC Crusher #2 - Portable; 1985-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Iron Mountain Ore Company → GDC Crusher #2 - Portable; 1985-03-01 to 1986-03-23; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Carlyle → GDC Crusher #2 - Portable; 1985-03-01 to 1986-03-23; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Carlyle → Iron Mountain Ore Company; 1985-03-01 to 1986-03-23; source msha-controller-operator-history
- **operator_operates_mine:** Gilbert Development Corp → GDC Crusher #2 - Portable; 1986-03-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve L  Gilbert → Gilbert Development Corp; 1986-03-24 to current/open; source msha-controller-operator-history