# Relationship history for MSHA mine 0800871

Current hierarchy: **Mosaic Company → Imc-Agrico → BIG FOUR**

- 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:** Mobil Corp → BIG FOUR; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Borden Chemical Division → BIG FOUR; 1950-01-01 to 1980-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Borden Inc → BIG FOUR; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Borden Inc → Borden Chemical Division; 1950-01-01 to 1980-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Cyprus Amax Minerals Company → BIG FOUR; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Amax Chemical Corp → BIG FOUR; 1980-07-01 to 1990-03-26; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Amax Minerals Company → Amax Chemical Corp; 1980-07-01 to 1990-03-26; source msha-controller-operator-history
- **operator_operates_mine:** Mobil Mining & Minerals Company → BIG FOUR; 1990-03-27 to 1996-12-14; source msha-controller-operator-history
- **controller_controls_operator:** Mobil Corp → Mobil Mining & Minerals Company; 1990-03-27 to 1996-12-14; source msha-controller-operator-history
- **controller_controls_mine:** Mosaic Company → BIG FOUR; 1993-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Imc-Agrico → BIG FOUR; 1996-12-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mosaic Company → Imc-Agrico; 1996-12-15 to current/open; source msha-controller-operator-history