# Relationship history for MSHA mine 0201608

Current hierarchy: **Taiheiyo Cement Corp → CalPortland Company → PANTANO**

- 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:** Arizona Portland Cement Company → PANTANO; 1950-01-01 to 1984-06-30; source msha-controller-operator-history
- **controller_controls_mine:** California Portland Cement Company → PANTANO; 1950-01-01 to 1984-06-30; source msha-controller-operator-history
- **controller_controls_operator:** California Portland Cement Company → Arizona Portland Cement Company; 1950-01-01 to 1984-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Arizona Portland Cement Company → PANTANO; 1984-07-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Calmat Company → PANTANO; 1984-07-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Calmat Company → Arizona Portland Cement Company; 1984-07-01 to 1990-09-30; source msha-controller-operator-history
- **operator_operates_mine:** CalPortland Company → PANTANO; 1990-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Taiheiyo Cement Corp → PANTANO; 1990-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Taiheiyo Cement Corp → CalPortland Company; 1990-10-01 to current/open; source msha-controller-operator-history