# Relationship history for MSHA mine 4201603

Current hierarchy: **Larry  Stubbs → Americo Rock & Sand → GLEN CANYON 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

- **operator_operates_mine:** General Rock & Sand → GLEN CANYON PIT; 1979-01-01 to 2000-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Merril  Jessop → GLEN CANYON PIT; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Merril  Jessop → General Rock & Sand; 1979-01-01 to 2000-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Americo Rock & Sand → GLEN CANYON PIT; 2000-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Larry  Stubbs → GLEN CANYON PIT; 2000-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Larry  Stubbs → Americo Rock & Sand; 2000-11-01 to current/open; source msha-controller-operator-history