# Relationship history for MSHA mine 2104107

Current hierarchy: **Kim  Davidson; Kevin  Davidson; Ronald  Davidson → Davidson Construction Inc → Sand Screw**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Ronald D  Davidson → Sand Screw; 1978-03-09 to 2025-07-15; source msha-controller-operator-history
- **operator_operates_mine:** Davidson Construction Inc → Sand Screw; 2025-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kim  Davidson et al → Sand Screw; 2025-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kim  Davidson et al → Davidson Construction Inc; 2025-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kevin  Davidson et al → Davidson Construction Inc; 2025-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald  Davidson et al → Davidson Construction Inc; 2025-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald D  Davidson → Davidson Construction Inc; 2025-07-16 to 2025-07-15; source msha-controller-operator-history