# Relationship history for MSHA mine 3607241

Current hierarchy: **Inter-Power/Ahlcon Partners LP → MAPLE COAL COMPANY → COLVER REFUSE SITE**

- 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:** Zev Energy Inc → COLVER REFUSE SITE; 1981-11-01 to 1988-03-09; source msha-controller-operator-history
- **controller_controls_mine:** Victor E  Zarilla → COLVER REFUSE SITE; 1981-11-01 to 1988-03-09; source msha-controller-operator-history
- **controller_controls_operator:** Victor E  Zarilla → Zev Energy Inc; 1981-11-01 to 1988-03-09; source msha-controller-operator-history
- **operator_operates_mine:** Maple Coal Company → COLVER REFUSE SITE; 1988-03-10 to 1993-05-01; source msha-controller-operator-history
- **controller_controls_mine:** Inter-Power USA Inc → COLVER REFUSE SITE; 1988-03-10 to 1993-05-01; source msha-controller-operator-history
- **controller_controls_operator:** Inter-Power USA Inc → Maple Coal Company; 1988-03-10 to 1993-05-01; source msha-controller-operator-history
- **operator_operates_mine:** Maple Coal Company → COLVER REFUSE SITE; 1993-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Inter-Power/Ahlcon Partners LP et al → COLVER REFUSE SITE; 1993-05-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Inter-Power/Ahlcon Partners LP et al → Maple Coal Company; 1993-05-02 to current/open; source msha-controller-operator-history