# Relationship history for MSHA mine 2902523

Current hierarchy: **Dale  Armstrong → Black Rock Services LLC → Black Rock Cinder Pit**

- 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:** Robert  Caldwell et al → Black Rock Cinder Pit; 2016-03-09 to 2024-01-01; source msha-controller-operator-history
- **operator_operates_mine:** Black Rock Services LLC → Black Rock Cinder Pit; 2020-10-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Caldwell et al → Black Rock Services LLC; 2020-10-21 to 2024-01-01; source msha-controller-operator-history
- **controller_controls_operator:** Dale  Armstrong et al → Black Rock Services LLC; 2020-10-21 to 2024-01-01; source msha-controller-operator-history
- **controller_controls_mine:** Dale  Armstrong → Black Rock Cinder Pit; 2024-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dale  Armstrong → Black Rock Services LLC; 2024-01-02 to current/open; source msha-controller-operator-history