# Relationship history for MSHA mine 3600130

Current hierarchy: **New Enterprise Stone & Lime Company Inc → New Enterprise Stone & Lime Co., Inc. → Denver 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:** New Enterprise Stone & Lime Company Inc → Denver Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** A G Kurtz & Sons Inc → Denver Quarry; 1950-01-01 to 1996-07-31; source msha-controller-operator-history
- **controller_controls_mine:** A Gary  Kurtz → Denver Quarry; 1950-01-01 to 1996-07-31; source msha-controller-operator-history
- **controller_controls_operator:** A Gary  Kurtz → A G Kurtz & Sons Inc; 1950-01-01 to 1996-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Martin Limestone Inc → Denver Quarry; 1996-08-01 to 2010-08-04; source msha-controller-operator-history
- **controller_controls_operator:** New Enterprise Stone & Lime Company Inc → Martin Limestone Inc; 1996-08-01 to 2010-08-04; source msha-controller-operator-history
- **operator_operates_mine:** New Enterprise Stone & Lime Co., Inc. → Denver Quarry; 2010-08-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** New Enterprise Stone & Lime Company Inc → New Enterprise Stone & Lime Co., Inc.; 2010-08-05 to current/open; source msha-controller-operator-history