# Relationship history for MSHA mine 3600183

Current hierarchy: **Graymont Ltd → Graymont (Pa) Inc → Buffalo Run 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:** Domtar Industries Inc → Buffalo Run Mine; 1950-01-01 to 1983-04-25; source msha-controller-operator-history
- **controller_controls_mine:** Domtar Inc → Buffalo Run Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Domtar Inc → Domtar Industries Inc; 1950-01-01 to 1983-04-25; source msha-controller-operator-history
- **operator_operates_mine:** Con-Lime Inc → Buffalo Run Mine; 1983-04-26 to 2001-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Irvin L  Confer → Buffalo Run Mine; 1983-04-26 to 2001-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Irvin L  Confer → Con-Lime Inc; 1983-04-26 to 2001-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Graymont Ltd → Buffalo Run Mine; 1998-06-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Graymont (Pa) Inc → Buffalo Run Mine; 2001-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Graymont Ltd → Graymont (Pa) Inc; 2001-06-01 to current/open; source msha-controller-operator-history