# Relationship history for MSHA mine 1509965

Current hierarchy: **Costain Group PLC → Costain Coal Inc → Prater Creek Mine #2**

- 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:** Costain Group PLC → Prater Creek Mine #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Schwab Charles F → Prater Creek Mine #2; 1975-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hawkeye Elkhorn Coal Company Inc → Prater Creek Mine #2; 1976-09-01 to 1978-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Schwab Charles F → Hawkeye Elkhorn Coal Company Inc; 1976-09-01 to 1978-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Hawkeye Elkhorn Coal Company Inc → Prater Creek Mine #2; 1978-09-01 to 1979-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Falcon Seaboard Inc → Prater Creek Mine #2; 1978-09-01 to 1979-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Falcon Seaboard Inc → Hawkeye Elkhorn Coal Company Inc; 1978-09-01 to 1979-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Hawkeye Services Corp → Prater Creek Mine #2; 1979-02-01 to 1987-05-17; source msha-controller-operator-history
- **controller_controls_mine:** Diamond Shamrock Corp → Prater Creek Mine #2; 1979-02-01 to 1987-05-17; source msha-controller-operator-history
- **controller_controls_operator:** Diamond Shamrock Corp → Hawkeye Services Corp; 1979-02-01 to 1987-05-17; source msha-controller-operator-history
- **operator_operates_mine:** Hawkeye Coal Company → Prater Creek Mine #2; 1987-05-18 to 1991-12-30; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc et al → Prater Creek Mine #2; 1987-05-18 to 1991-12-30; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Hawkeye Coal Company; 1987-05-18 to 1991-12-30; source msha-controller-operator-history
- **operator_operates_mine:** Costain Coal Inc → Prater Creek Mine #2; 1991-12-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Costain Group PLC → Costain Coal Inc; 1991-12-31 to current/open; source msha-controller-operator-history