# Relationship history for MSHA mine 4606078

Current hierarchy: **Robertson Jack → Deep Ford Mining Company Inc → 5 Block 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:** Spruce Knob Mining Company → 5 Block Mine; 1979-11-01 to 1980-09-07; source msha-controller-operator-history
- **controller_controls_mine:** Mason Martin E → 5 Block Mine; 1979-11-01 to 1980-09-07; source msha-controller-operator-history
- **controller_controls_operator:** Mason Martin E → Spruce Knob Mining Company; 1979-11-01 to 1980-09-07; source msha-controller-operator-history
- **controller_controls_mine:** Robertson Glen → 5 Block Mine; 1979-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Deep Ford Mining Company Inc → 5 Block Mine; 1980-09-08 to 1981-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Robertson Glen → Deep Ford Mining Company Inc; 1980-09-08 to 1981-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Deep Ford Mining Company Inc → 5 Block Mine; 1981-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robertson Jack → 5 Block Mine; 1981-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robertson Jack → Deep Ford Mining Company Inc; 1981-10-01 to current/open; source msha-controller-operator-history