# Relationship history for MSHA mine 4604685

Current hierarchy: **Dever Dennis → 3-Z Company Inc → No 1 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:** Three Z Company → No 1 Mine; 1975-08-01 to 1977-07-26; source msha-controller-operator-history
- **controller_controls_mine:** Zickefoose Vaughan → No 1 Mine; 1975-08-01 to 1977-07-26; source msha-controller-operator-history
- **controller_controls_operator:** Zickefoose Vaughan → Three Z Company; 1975-08-01 to 1977-07-26; source msha-controller-operator-history
- **operator_operates_mine:** 3-Z Company Inc → No 1 Mine; 1977-07-27 to 1977-09-06; source msha-controller-operator-history
- **controller_controls_mine:** Brown Charles T → No 1 Mine; 1977-07-27 to 1977-09-06; source msha-controller-operator-history
- **controller_controls_operator:** Brown Charles T → 3-Z Company Inc; 1977-07-27 to 1977-09-06; source msha-controller-operator-history
- **operator_operates_mine:** 3-Z Company Inc → No 1 Mine; 1977-09-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dever Dennis → No 1 Mine; 1977-09-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dever Dennis → 3-Z Company Inc; 1977-09-07 to current/open; source msha-controller-operator-history