# Relationship history for MSHA mine 4102991

Current hierarchy: **Daniel L  Skurlock → Danco Sand → DANCO SAND**

- 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:** Bob Meals Sand & Gravel Inc → DANCO SAND; 1980-01-01 to 1995-12-03; source msha-controller-operator-history
- **controller_controls_mine:** Bob  Meals → DANCO SAND; 1980-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bob  Meals → Bob Meals Sand & Gravel Inc; 1980-01-01 to 1995-12-03; source msha-controller-operator-history
- **operator_operates_mine:** Danco Sand → DANCO SAND; 1995-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Daniel L  Skurlock → DANCO SAND; 1995-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Daniel L  Skurlock → Danco Sand; 1995-12-04 to current/open; source msha-controller-operator-history