# Relationship history for MSHA mine 2902000

Current hierarchy: **Bill B  Armstrong Jr → Armstrong Construction Company Inc → Mobile #Two**

- 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:** Bill B  Armstrong Jr  et al → Mobile #Two; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Armstrong Construction Company Inc → Mobile #Two; 1985-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill B  Armstrong Jr  et al → Armstrong Construction Company Inc; 1985-09-01 to current/open; source msha-controller-operator-history