# Relationship history for MSHA mine 1517437

Current hierarchy: **Horizon Natural Resources Incorporated → Straight Creek Coal Resources Co → Copeland Mine**

- 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:** Thomas C  Lackey → Copeland Mine; 1987-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Charles  Collins → Copeland Mine; 1992-02-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Unicorn Mining Inc → Copeland Mine; 1993-08-01 to 1999-08-30; source msha-controller-operator-history
- **controller_controls_operator:** Thomas C  Lackey → Unicorn Mining Inc; 1993-08-01 to 1999-08-30; source msha-controller-operator-history
- **controller_controls_mine:** Carl  Kirk et al → Copeland Mine; 1998-02-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Horizon Natural Resources Incorporated → Copeland Mine; 1998-06-29 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** North Star Mining Inc → Copeland Mine; 1999-08-31 to 2001-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Carl  Kirk et al → North Star Mining Inc; 1999-08-31 to 2001-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Calvary Coal Company Inc → Copeland Mine; 2001-06-01 to 2002-03-12; source msha-controller-operator-history
- **controller_controls_operator:** Charles  Collins → Calvary Coal Company Inc; 2001-06-01 to 2002-03-12; source msha-controller-operator-history
- **operator_operates_mine:** Straight Creek Coal Resources Co → Copeland Mine; 2002-03-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Horizon Natural Resources Incorporated → Straight Creek Coal Resources Co; 2002-03-13 to current/open; source msha-controller-operator-history