# Relationship history for MSHA mine 0100405

Current hierarchy: **Robertson David S & Assoc Ltd → Robertson & Assoc (Al) Inc → Fabius Strip 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:** Arch Coal Company Inc → Fabius Strip Mine; 1950-01-01 to 1974-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc et al → Fabius Strip Mine; 1950-01-01 to 1974-08-14; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Arch Coal Company Inc; 1950-01-01 to 1974-08-14; source msha-controller-operator-history
- **operator_operates_mine:** Robertson & Assoc (Al) Inc → Fabius Strip Mine; 1974-08-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robertson David S & Assoc Ltd → Fabius Strip Mine; 1974-08-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robertson David S & Assoc Ltd → Robertson & Assoc (Al) Inc; 1974-08-15 to current/open; source msha-controller-operator-history