# Relationship history for MSHA mine 1901141

Current hierarchy: **Darren  Leinbach; John M  Hess; Darvin J  Hess; Dennis L  Nolt; Kelvin J → Hilltown Sand & Gravel → Montgomery Sand & Gravel**

- 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

- **operator_operates_mine:** PECKHAM ENTERPRISES LLC → Montgomery Sand & Gravel; 2005-04-26 to 2019-03-11; source msha-controller-operator-history
- **controller_controls_mine:** Nancy M  Peckham et al → Montgomery Sand & Gravel; 2005-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nancy M  Peckham et al → PECKHAM ENTERPRISES LLC; 2005-04-26 to 2019-03-11; source msha-controller-operator-history
- **controller_controls_operator:** Charles R  Peckham et al → PECKHAM ENTERPRISES LLC; 2005-04-26 to 2019-03-11; source msha-controller-operator-history
- **operator_operates_mine:** Hilltown Sand & Gravel → Montgomery Sand & Gravel; 2019-03-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jon  Hollingshead et al → Montgomery Sand & Gravel; 2019-03-12 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Jon  Hollingshead et al → Hilltown Sand & Gravel; 2019-03-12 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_operator:** J Melvin  Hess et al → Hilltown Sand & Gravel; 2019-03-12 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_mine:** John M  Hess et al → Montgomery Sand & Gravel; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John M  Hess et al → Hilltown Sand & Gravel; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darren  Leinbach et al → Hilltown Sand & Gravel; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kelvin J  Mast et al → Hilltown Sand & Gravel; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darvin J  Hess et al → Hilltown Sand & Gravel; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dennis L  Nolt et al → Hilltown Sand & Gravel; 2021-01-01 to current/open; source msha-controller-operator-history