# Relationship history for MSHA mine 0502658

Current hierarchy: **Roaring Fork Coal Corp & Lark Mng Corp → Snowmass Coal Company → Thompson Creek No 1**

- 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:** Anschutz Coal Corp → Thompson Creek No 1; 1975-01-01 to 1979-01-04; source msha-controller-operator-history
- **controller_controls_mine:** Anschutz Corp → Thompson Creek No 1; 1975-01-01 to 1979-01-04; source msha-controller-operator-history
- **controller_controls_operator:** Anschutz Corp → Anschutz Coal Corp; 1975-01-01 to 1979-01-04; source msha-controller-operator-history
- **controller_controls_mine:** Roaring Fork Coal Corp & Lark Mng Corp → Thompson Creek No 1; 1978-12-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Snowmass Coal Company → Thompson Creek No 1; 1979-01-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roaring Fork Coal Corp & Lark Mng Corp → Snowmass Coal Company; 1979-01-05 to current/open; source msha-controller-operator-history