# Relationship history for MSHA mine 4404926

Current hierarchy: **M A Hanna Company; W R Grace Company → Paramont Mining Corp → No 2 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:** Barber Oil Corp → No 2 Mine; 1976-09-21 to 1981-04-29; source msha-controller-operator-history
- **operator_operates_mine:** Paramont Mining Corp → No 2 Mine; 1978-01-01 to 1981-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Barber Oil Corp → Paramont Mining Corp; 1978-01-01 to 1981-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Paramont Mining Corp → No 2 Mine; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** M A Hanna Company et al → No 2 Mine; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** M A Hanna Company et al → Paramont Mining Corp; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W R Grace Company et al → Paramont Mining Corp; 1981-04-01 to current/open; source msha-controller-operator-history