# Relationship history for MSHA mine 3602923

Current hierarchy: **Jolly Jessie J → North Cambria Fuel Company Inc → D B #1 Strip**

- 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:** North Cambria Fuel Company → D B #1 Strip; 1950-01-01 to 1978-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Bearer Martin L → D B #1 Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bearer Martin L → North Cambria Fuel Company; 1950-01-01 to 1978-11-30; source msha-controller-operator-history
- **operator_operates_mine:** North Cambria Fuel Company Inc → D B #1 Strip; 1978-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jolly Jessie J → D B #1 Strip; 1978-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jolly Jessie J → North Cambria Fuel Company Inc; 1978-12-01 to current/open; source msha-controller-operator-history