# Relationship history for MSHA mine 3401088

Current hierarchy: **Curtis C W → Noble Sand Company → Noble Sand 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Big Eight Construction Company → Noble Sand Company; 1978-03-09 to 1983-03-09; source msha-controller-operator-history
- **controller_controls_mine:** Nelson E C → Noble Sand Company; 1978-03-09 to 1983-03-09; source msha-controller-operator-history
- **controller_controls_operator:** Nelson E C → Big Eight Construction Company; 1978-03-09 to 1983-03-09; source msha-controller-operator-history
- **operator_operates_mine:** Noble Sand Company → Noble Sand Company; 1983-03-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Curtis C W → Noble Sand Company; 1983-03-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Curtis C W → Noble Sand Company; 1983-03-10 to current/open; source msha-controller-operator-history