# Relationship history for MSHA mine 1512233

Current hierarchy: **Varney Emery & Glenn → Mount Calvery Coal Company Inc → No2 (D)**

- 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:** Preece Homer & George → No2 (D); 1977-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Coleman Coal Company Inc → No2 (D); 1980-02-01 to 1980-04-22; source msha-controller-operator-history
- **controller_controls_mine:** Coleman Dock A Et Al → No2 (D); 1980-02-01 to 1981-04-13; source msha-controller-operator-history
- **controller_controls_operator:** Coleman Dock A Et Al → Coleman Coal Company Inc; 1980-02-01 to 1980-04-22; source msha-controller-operator-history
- **operator_operates_mine:** Preece Enterprises Inc → No2 (D); 1980-04-23 to 1983-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Preece Homer & George → Preece Enterprises Inc; 1980-04-23 to 1983-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Varney Emery & Glenn → No2 (D); 1983-02-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mount Calvery Coal Company Inc → No2 (D); 1983-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Varney Emery & Glenn → Mount Calvery Coal Company Inc; 1983-06-23 to current/open; source msha-controller-operator-history