# Relationship history for MSHA mine 1200007

Current hierarchy: **Heidelberg Materials AG → Hanson Aggregates Midwest, LLC → North Vernon 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

- **controller_controls_mine:** Koppers Company Inc → North Vernon Quarry; 1950-01-01 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Berry Materials Corp → North Vernon Quarry; 1950-01-01 to 1986-10-29; source msha-controller-operator-history
- **controller_controls_mine:** Nathaniel  Huffman  et al → North Vernon Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nathaniel  Huffman  et al → Berry Materials Corp; 1950-01-01 to 1986-10-29; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky Stone Company → North Vernon Quarry; 1986-10-30 to 1988-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Koppers Company Inc → Kentucky Stone Company; 1986-10-30 to 1988-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Aggregates Midwest, LLC → North Vernon Quarry; 1988-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → North Vernon Quarry; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Aggregates Midwest, LLC; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → North Vernon Quarry; 2007-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Hanson Aggregates Midwest, LLC; 2007-08-23 to current/open; source msha-controller-operator-history