# Relationship history for MSHA mine 5100056

Current hierarchy: **Knife River Corporation → Hawaiian Cement → Barbers Point Mill**

- 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:** Cyprus Hawaiian Cement Corp → Barbers Point Mill; 1950-01-01 to 1980-09-21; source msha-controller-operator-history
- **controller_controls_mine:** Cyprus Mines Corp → Barbers Point Mill; 1950-01-01 to 1980-09-21; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Mines Corp → Cyprus Hawaiian Cement Corp; 1950-01-01 to 1980-09-21; source msha-controller-operator-history
- **operator_operates_mine:** Cyprus Hawaiin Cement Corp → Barbers Point Mill; 1980-09-22 to 1982-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Cyprus Amax Minerals Company → Barbers Point Mill; 1980-09-22 to 1982-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Amax Minerals Company → Cyprus Hawaiin Cement Corp; 1980-09-22 to 1982-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Lone Star Hawaii Cement Corp → Barbers Point Mill; 1982-10-01 to 1985-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Lone Star Industries Inc → Barbers Point Mill; 1982-10-01 to 1985-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Lone Star Industries Inc → Lone Star Hawaii Cement Corp; 1982-10-01 to 1985-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Hawaiian Cement → Barbers Point Mill; 1985-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** MDU Resources Group Inc → Barbers Point Mill; 1985-10-01 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_operator:** MDU Resources Group Inc → Hawaiian Cement; 1985-10-01 to 2023-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Barbers Point Mill; 2023-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Hawaiian Cement; 2023-06-01 to current/open; source msha-controller-operator-history