# Relationship history for MSHA mine 1508057

Current hierarchy: **Michael  Puskarich → Bluegrass Mining → No 1 Surface**

- 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:** D & W Enterprises → No 1 Surface; 1975-02-14 to 1977-03-29; source msha-controller-operator-history
- **controller_controls_mine:** Davis Gene & Arnold Wells → No 1 Surface; 1975-02-14 to 1977-03-29; source msha-controller-operator-history
- **controller_controls_operator:** Davis Gene & Arnold Wells → D & W Enterprises; 1975-02-14 to 1977-03-29; source msha-controller-operator-history
- **operator_operates_mine:** Black Mountain Coal Company → No 1 Surface; 1977-03-30 to 1977-09-15; source msha-controller-operator-history
- **controller_controls_mine:** Schmid Duane → No 1 Surface; 1977-03-30 to 1977-09-15; source msha-controller-operator-history
- **controller_controls_operator:** Schmid Duane → Black Mountain Coal Company; 1977-03-30 to 1977-09-15; source msha-controller-operator-history
- **operator_operates_mine:** Bluegrass Mining → No 1 Surface; 1977-09-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael  Puskarich  et al → No 1 Surface; 1977-09-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael  Puskarich  et al → Bluegrass Mining; 1977-09-16 to current/open; source msha-controller-operator-history