# Relationship history for MSHA mine 4103796

Current hierarchy: **Myrna  Pierce; Howard K  Pierce → Howard Pierce & Sons Stone Company LLC → PIERCE PIT**

- 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:** Howard B Pierce Stone Company → PIERCE PIT; 1993-12-01 to 2009-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Howard B  Pierce → PIERCE PIT; 1993-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Howard B  Pierce → Howard B Pierce Stone Company; 1993-12-01 to 2009-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Howard Pierce & Sons Stone Company LLC → PIERCE PIT; 2009-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Howard K  Pierce et al → PIERCE PIT; 2009-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Howard K  Pierce et al → Howard Pierce & Sons Stone Company LLC; 2009-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Myrna  Pierce et al → Howard Pierce & Sons Stone Company LLC; 2009-04-01 to current/open; source msha-controller-operator-history