# Relationship history for MSHA mine 0901041

Current hierarchy: **Tarmac Plc → Sand South-Div/Silver Sand Company → Hortense Mine**

- 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:** Sand South Inc → Hortense Mine; 1989-07-01 to 1990-04-19; source msha-controller-operator-history
- **controller_controls_mine:** Swinson John → Hortense Mine; 1989-07-01 to 1990-04-19; source msha-controller-operator-history
- **controller_controls_operator:** Swinson John → Sand South Inc; 1989-07-01 to 1990-04-19; source msha-controller-operator-history
- **operator_operates_mine:** Sand South-Div/Silver Sand Company → Hortense Mine; 1990-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Tarmac Plc → Hortense Mine; 1990-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tarmac Plc → Sand South-Div/Silver Sand Company; 1990-04-20 to current/open; source msha-controller-operator-history