# Relationship history for MSHA mine 3609548

Current hierarchy: **Robert  Burns → Keystone Anthracite Company Incorporated → Trevorton Strip**

- 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:** Michael R  Burns → Trevorton Strip; 1994-11-01 to 2011-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Keystone Anthracite Company Incorporated → Trevorton Strip; 2007-08-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael R  Burns → Keystone Anthracite Company Incorporated; 2007-08-09 to 2011-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Robert  Burns → Trevorton Strip; 2011-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Burns → Keystone Anthracite Company Incorporated; 2011-03-01 to current/open; source msha-controller-operator-history