# Relationship history for MSHA mine 1513428

Current hierarchy: **Horizon Natural Resources Incorporated → Addwest Mining Inc → Knottsville 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:** Lanham Coal Company Inc → Knottsville Mine; 1982-03-01 to 1989-06-19; source msha-controller-operator-history
- **controller_controls_mine:** Lanham John → Knottsville Mine; 1982-03-01 to 1989-06-19; source msha-controller-operator-history
- **controller_controls_operator:** Lanham John → Lanham Coal Company Inc; 1982-03-01 to 1989-06-19; source msha-controller-operator-history
- **controller_controls_mine:** Horizon Natural Resources Incorporated → Knottsville Mine; 1986-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Addwest Mining Inc → Knottsville Mine; 1989-06-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Horizon Natural Resources Incorporated → Addwest Mining Inc; 1989-06-20 to current/open; source msha-controller-operator-history