# Relationship history for MSHA mine 0202570

Current hierarchy: **Carney Dennis J → Black Mountain Sand & Gravel Company → Black Mountain Sand & Gravel Company**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Golden Valley Sand & Rock Inc → Black Mountain Sand & Gravel Company; 1992-02-01 to 1993-02-24; source msha-controller-operator-history
- **controller_controls_mine:** Christian Gerald → Black Mountain Sand & Gravel Company; 1992-02-01 to 1993-02-24; source msha-controller-operator-history
- **controller_controls_operator:** Christian Gerald → Golden Valley Sand & Rock Inc; 1992-02-01 to 1993-02-24; source msha-controller-operator-history
- **operator_operates_mine:** Black Mountain Sand & Gravel Company → Black Mountain Sand & Gravel Company; 1993-02-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Carney Dennis J → Black Mountain Sand & Gravel Company; 1993-02-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carney Dennis J → Black Mountain Sand & Gravel Company; 1993-02-25 to current/open; source msha-controller-operator-history