# PORTABLE CRUSHER

- **MSHA mine ID:** 2102623
- **Status:** Intermittent
- **Type / commodity:** Surface / Construction Sand and Gravel
- **Location:** Beltrami, MN
- **Operator:** NORTHERN AGGREGATE INC.
- **Controller:** Schulke Family Trust; Eric  Schulke; Kyle  Schulke
- **Public source rows linked:** 441
- **Source coverage:** 12 / 20
- **Generated:** 2026-10-13T11:26:59.401Z

## Current entity hierarchy

**Schulke Family Trust; Eric  Schulke; Kyle  Schulke (0185482) → NORTHERN AGGREGATE INC. (L18256) → PORTABLE CRUSHER (2102623)**

Current identity source: `msha-mines`. This is a current snapshot, not a historical claim.

## Controller and operator valid-time history

- **Ronald D  Davidson → Davidson Construction:** 1978-03-09 through 1987-06-17; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Myron  Olberg → M & J Construction:** 1987-06-18 through 2001-03-05; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Rick  Schulke → NORTHERN AGGREGATE INC.:** 2001-03-06 through 2024-06-05; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Sharron  Olberg et al → M & J Construction:** 2013-10-21 through 2001-03-05; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Jeffrey  Olberg et al → M & J Construction:** 2013-10-21 through 2001-03-05; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Schulke Family Trust et al → NORTHERN AGGREGATE INC.:** 2024-06-06 through current/open; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Eric  Schulke et al → NORTHERN AGGREGATE INC.:** 2024-06-06 through current/open; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Kyle  Schulke et al → NORTHERN AGGREGATE INC.:** 2024-06-06 through current/open; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Ronald  Davidson et al → Davidson Construction:** 2025-07-16 through 1987-06-17; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Kevin  Davidson et al → Davidson Construction:** 2025-07-16 through 1987-06-17; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.
- **Kim  Davidson et al → Davidson Construction:** 2025-07-16 through 1987-06-17; derived from co-tenure at mine 2102623; source `msha-controller-operator-history`.

- History rows: 11
- Typed edges: 20
- Interval anomalies: 5
- Valid-time bounds: inclusive; date granularity; null end means open-ended in the upstream history row; not independent proof of present control.
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00.

## Assessment signals

1. **SAFETY — 0 since 2021:** Accidents and injuries 0 historical accident/injury rows; 0 coded fatalities and 0 lost days across the published record.
2. **COMPLIANCE — 12 since 2021:** Violations and penalties 102 violation rows across the full record; 31 carry an S&S flag and $36,388 appears in current assessed amounts.
3. **HEALTH — 19 samples:** Occupational health samples 19 personal. 1 personal-sample rows have a published C/E ratio above 1; 0 noise rows have an action-level or PEL dose above 100%. These are separate measures, not a silica exceedance count. Silica results and sample status are shown separately.
4. **PRODUCTION — 0 tons:** Quarterly production and employment 815 employee hours and 5 summed average employees across reported subunits in the latest published quarter.
5. **LEGAL — 21 linked rows:** Contests, conferences and decisions 10 contested-violation rows, 10 civil-penalty docket/decision rows, and 1 conference records linked by issuance number.
6. **CONTRACTORS — 0 linked entities:** Contractors Contractors are linked through this mine’s violation or accident records. Their production and hours cover all their operations, so they are not included in this mine’s totals.
7. **INSPECTIONS — 9 since 2021:** Inspections 41 inspection events and 530 published inspection hours across the historical record.

## EIA annual operating context

No matched record in the 2024 EIA coal-public workbook. This may be inapplicable for a non-coal operation.

## Recent Title 30 crosswalk

Snapshot current through 2026-08-19.

- **30 CFR 56.9300 — Berms or guardrails.** (2 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-H/section-56.9300
- **30 CFR 56.14132 — Horns and backup alarms.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14132
- **30 CFR 56.5001 — Exposure limits for airborne contaminants.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-D/section-56.5001
- **30 CFR 56.15005 — Safety belts and lines.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-N/section-56.15005
- **30 CFR 56.12018 — Identification of power switches.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12018
- **30 CFR 56.12004 — Electrical conductors.** (3 retained recent rows) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-K/section-56.12004
- **30 CFR 56.14107 — Moving machine parts.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-M/section-56.14107
- **30 CFR 56.1000 — Notification of commencement of operations and closing of mines.** (1 retained recent row) — https://www.ecfr.gov/current/title-30/chapter-I/subchapter-K/part-56/subpart-A/section-56.1000

## Source coverage

- **Addresses of Record:** 1 rows; 2011-06-30 through 2011-06-30; source ID `msha-addresses`
- **Assessed Violations:** 100 rows; 2001-10-09 through 2026-07-14; source ID `msha-assessed-violations`
- **Civil Penalty Dockets and Decisions:** 10 rows; 2014-10-07 through 2015-03-13; source ID `msha-civil-penalty-dockets-decisions`
- **Conferences:** 1 rows; 2016-08-12 through 2016-08-12; source ID `msha-conferences`
- **Contested Violations:** 10 rows; 2013-09-04 through 2013-09-04; source ID `msha-contested-violations`
- **Controller and Operator History:** 11 rows; 1978-03-09 through 2001-03-06; source ID `msha-controller-operator-history`
- **Inspections:** 41 rows; 2000-05-25 through 2026-07-14; source ID `msha-inspections`
- **Mine Employment and Production — Quarterly:** 116 rows; unknown through unknown; source ID `msha-mine-production-quarterly`
- **Mine Employment and Production — Yearly:** 29 rows; unknown through unknown; source ID `msha-mine-production-yearly`
- **Mines:** 1 rows; unknown through unknown; source ID `msha-mines`
- **Metal and Nonmetal Personal Health Samples:** 19 rows; 2001-10-11 through 2025-09-24; source ID `msha-personal-health-samples`
- **Violations:** 102 rows; 2001-10-09 through 2026-07-14; source ID `msha-violations`

## Caveats

- This is public-record decision support, not legal advice or an official MSHA record.
- Missing data can indicate no event, publication delay, an unresolved identity, or inapplicability.
- Contractor production data is entity-level and is not attributed to this mine.

## Alternate representations

- HTML: `/mines/portable-crusher-2102623`
- JSON: `/api/v1/mines/portable-crusher-2102623`
- Silica records, units, sample status and quarterly means: `/api/v1/mines/2102623/silica` (snapshot year by default; `?year=all` for history; `&format=csv` for all matching rows)
- Relationship JSON: `/api/v1/mines/2102623/relationships`
- MCP resource: `mine://2102623/assessment`
- Complete Title 30 corpus: `/data/title30-sections.json`