# Relationship history for MSHA mine 3200968

Current hierarchy: **Mark  Berset → J3 Advanced Engineering Technologies Inc. → Crusher #1**

- 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:** Harper Investments Inc → Crusher #1; 1978-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Harper Sand & Gravel → Crusher #1; 2012-05-17 to 2015-05-10; source msha-controller-operator-history
- **controller_controls_operator:** Harper Investments Inc → Harper Sand & Gravel; 2012-05-17 to 2015-05-10; source msha-controller-operator-history
- **operator_operates_mine:** J3 Advanced Engineering Technologies Inc. → Crusher #1; 2015-05-11 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark  Berset et al → Crusher #1; 2015-05-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Berset et al → J3 Advanced Engineering Technologies Inc.; 2015-05-11 to current/open; source msha-controller-operator-history