# Relationship history for MSHA mine 1510606

Current hierarchy: **Harold K  Simpson → S & B Coal Company Inc → No 1 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

- **controller_controls_mine:** Paramount Drilling Corp → No 1 Mine; 1976-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** King Coal Company → No 1 Mine; 1977-06-01 to 1982-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Paramount Drilling Corp → King Coal Company; 1977-06-01 to 1982-03-31; source msha-controller-operator-history
- **operator_operates_mine:** S & B Coal Company Inc → No 1 Mine; 1982-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harold K  Simpson → No 1 Mine; 1982-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold K  Simpson → S & B Coal Company Inc; 1982-04-01 to current/open; source msha-controller-operator-history