# Relationship history for MSHA mine 3607462

Current hierarchy: **Gene B  Gangloff → Hecla Machinery & Equipment Company → Harwood Stockpile**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Gene B  Gangloff → Harwood Stockpile; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Keim Ralph A & George W Tallman → Harwood Stockpile; 1979-10-01 to 1983-06-06; source msha-controller-operator-history
- **operator_operates_mine:** K & T Coal Company → Harwood Stockpile; 1983-05-01 to 1983-06-06; source msha-controller-operator-history
- **controller_controls_operator:** Keim Ralph A & George W Tallman → K & T Coal Company; 1983-05-01 to 1983-06-06; source msha-controller-operator-history
- **operator_operates_mine:** Hecla Machinery & Equipment Company → Harwood Stockpile; 1983-06-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gene B  Gangloff → Hecla Machinery & Equipment Company; 1983-06-07 to current/open; source msha-controller-operator-history