# Relationship history for MSHA mine 3606332

Current hierarchy: **Kerry L  Mears → Mears Enterprises Inc → #1 Cleaning Plant**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Johnstown Coal & Coke Company → #1 Cleaning Plant; 1977-02-01 to 1983-04-19; source msha-controller-operator-history
- **controller_controls_mine:** Johnstown Coal & Coke Company → #1 Cleaning Plant; 1977-02-01 to 1983-04-19; source msha-controller-operator-history
- **controller_controls_operator:** Johnstown Coal & Coke Company → Johnstown Coal & Coke Company; 1977-02-01 to 1983-04-19; source msha-controller-operator-history
- **controller_controls_mine:** Kerry L  Mears → #1 Cleaning Plant; 1980-01-31 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mears Enterprises Inc → #1 Cleaning Plant; 1983-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kerry L  Mears → Mears Enterprises Inc; 1983-04-20 to current/open; source msha-controller-operator-history