# Relationship history for MSHA mine 3606568

Current hierarchy: **Trovinger Herbert-Joe Cromyak → Mary Brock Contracting Company → Sharp Mt Tract**

- 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:** Mucklow Russell → Sharp Mt Tract; 1977-02-23 to 1980-07-10; source msha-controller-operator-history
- **operator_operates_mine:** Birnen Coal Company Inc → Sharp Mt Tract; 1977-12-01 to 1980-07-06; source msha-controller-operator-history
- **controller_controls_operator:** Mucklow Russell → Birnen Coal Company Inc; 1977-12-01 to 1980-07-06; source msha-controller-operator-history
- **operator_operates_mine:** Birnen Coal Company Inc → Sharp Mt Tract; 1980-07-07 to 1982-06-14; source msha-controller-operator-history
- **controller_controls_mine:** Petersville Sleigh Ltd Et Al → Sharp Mt Tract; 1980-07-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Petersville Sleigh Ltd Et Al → Birnen Coal Company Inc; 1980-07-07 to 1982-06-14; source msha-controller-operator-history
- **operator_operates_mine:** Par-Four Mining Corp → Sharp Mt Tract; 1982-06-15 to 1983-08-30; source msha-controller-operator-history
- **controller_controls_mine:** Troup Warren-Edward Powell Et Al → Sharp Mt Tract; 1982-06-15 to 1983-08-30; source msha-controller-operator-history
- **controller_controls_operator:** Troup Warren-Edward Powell Et Al → Par-Four Mining Corp; 1982-06-15 to 1983-08-30; source msha-controller-operator-history
- **operator_operates_mine:** Mary Brock Contracting Company → Sharp Mt Tract; 1983-08-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Trovinger Herbert-Joe Cromyak Et Al → Sharp Mt Tract; 1983-08-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Trovinger Herbert-Joe Cromyak Et Al → Mary Brock Contracting Company; 1983-08-31 to current/open; source msha-controller-operator-history