# Relationship history for MSHA mine 0101702

Current hierarchy: **MidAmerican Energy Holdings Company → Sand Mountain Minerals Inc → Gibbs No 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Gibbs Don → Gibbs No 2; 1976-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sand Mountain Mineral Company → Gibbs No 2; 1977-01-01 to 1980-03-24; source msha-controller-operator-history
- **controller_controls_operator:** Gibbs Don → Sand Mountain Mineral Company; 1977-01-01 to 1980-03-24; source msha-controller-operator-history
- **operator_operates_mine:** Sand Mountain Minerals Inc → Gibbs No 2; 1980-03-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** MidAmerican Energy Holdings Company → Gibbs No 2; 1980-03-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** MidAmerican Energy Holdings Company → Sand Mountain Minerals Inc; 1980-03-25 to current/open; source msha-controller-operator-history