# Relationship history for MSHA mine 3500630

Current hierarchy: **Shawn  Teevin; Tom  Fischer → Teevin & Fischer Quarry, LLC. → Traprock Quarry**

- 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:** Howard E Johnson & Sons Construction Co Inc → Traprock Quarry; 1950-01-01 to 2000-08-16; source msha-controller-operator-history
- **controller_controls_mine:** Bruce H  Johnson → Traprock Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bruce H  Johnson → Howard E Johnson & Sons Construction Co Inc; 1950-01-01 to 2000-08-16; source msha-controller-operator-history
- **operator_operates_mine:** H. E.  Johnson & Sons Const., Inc. → Traprock Quarry; 2000-08-17 to 2006-09-24; source msha-controller-operator-history
- **controller_controls_mine:** David M  Larson → Traprock Quarry; 2003-07-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David M  Larson → H. E.  Johnson & Sons Const., Inc.; 2003-07-16 to 2006-09-24; source msha-controller-operator-history
- **operator_operates_mine:** Teevin & Fischer Quarry, LLC. → Traprock Quarry; 2006-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Shawn  Teevin et al → Traprock Quarry; 2006-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shawn  Teevin et al → Teevin & Fischer Quarry, LLC.; 2006-09-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tom  Fischer et al → Teevin & Fischer Quarry, LLC.; 2006-09-25 to current/open; source msha-controller-operator-history