# Relationship history for MSHA mine 4102986

Current hierarchy: **Norsworthy John → Sand & Equipment → Sand Pit #2**

- 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:** Fresno E & B Sand → Sand Pit #2; 1980-03-01 to 1981-06-01; source msha-controller-operator-history
- **controller_controls_mine:** B H  Goodman  et al → Sand Pit #2; 1980-03-01 to 1981-06-01; source msha-controller-operator-history
- **controller_controls_operator:** B H  Goodman  et al → Fresno E & B Sand; 1980-03-01 to 1981-06-01; source msha-controller-operator-history
- **controller_controls_mine:** Norsworthy John → Sand Pit #2; 1981-04-20 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sand & Equipment → Sand Pit #2; 1981-06-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Norsworthy John → Sand & Equipment; 1981-06-02 to current/open; source msha-controller-operator-history