# Relationship history for MSHA mine 1200937

Current hierarchy: **N S C Corp; Sibo Services Inc → Nugent Sand Company → Columbus Plant**

- 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:** Spray Sand & Gravel Inc → Columbus Plant; 1950-01-01 to 1984-09-17; source msha-controller-operator-history
- **controller_controls_mine:** William  Spray → Columbus Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William  Spray → Spray Sand & Gravel Inc; 1950-01-01 to 1984-09-17; source msha-controller-operator-history
- **controller_controls_mine:** N S C Corp et al → Columbus Plant; 1984-07-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Spray Aggregates Inc → Columbus Plant; 1984-09-18 to 1994-02-28; source msha-controller-operator-history
- **controller_controls_mine:** R C  Heuhe → Columbus Plant; 1984-09-18 to 1994-02-28; source msha-controller-operator-history
- **controller_controls_operator:** R C  Heuhe → Spray Aggregates Inc; 1984-09-18 to 1994-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Nugent Sand Company → Columbus Plant; 1994-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** N S C Corp et al → Nugent Sand Company; 1994-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sibo Services Inc et al → Nugent Sand Company; 1994-03-01 to current/open; source msha-controller-operator-history