# Relationship history for MSHA mine 3303709

Current hierarchy: **Reichman Kenneth R → Solid Fuel Inc → Solid Fuel Mine #1**

- 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:** Fuel-Tec Inc → Solid Fuel Mine #1; 1978-10-01 to 1979-09-17; source msha-controller-operator-history
- **controller_controls_mine:** Swartzman Frank → Solid Fuel Mine #1; 1978-10-01 to 1979-09-17; source msha-controller-operator-history
- **controller_controls_operator:** Swartzman Frank → Fuel-Tec Inc; 1978-10-01 to 1979-09-17; source msha-controller-operator-history
- **operator_operates_mine:** Solid Fuel Inc → Solid Fuel Mine #1; 1979-09-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Reichman Kenneth R → Solid Fuel Mine #1; 1979-09-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Reichman Kenneth R → Solid Fuel Inc; 1979-09-18 to current/open; source msha-controller-operator-history