# Relationship history for MSHA mine 0201904

Current hierarchy: **C William  Nichols → Sundial Stone Company → Sundial Stone 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:** Sundial Stone Company → Sundial Stone Company; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** C William  Nichols → Sundial Stone Company; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** C William  Nichols → Sundial Stone Company; 1979-01-01 to current/open; source msha-controller-operator-history