Grub Stake Gulch Placer – Technical & Historical Report (Mineral County, MT)

Prepared for:  Marlene Affeld

Oregon Gulch Exploration

Project: Oregon Gulch / Big Flat Placer Development (Cedar Creek District)

Claim:  Grub Stake Gulch Placer – 120 acres

Legal:  NW¼, Protracted Block 41, T15N R28W, Mineral County, Montana

1) Claim Overview

• Type: Unpatented placer claim (120 ac).

• District: Cedar Creek Historic Mining District (Oregon Gulch / Big Flat system).

• Hydrologic setting: Side-gulch system draining toward Oregon Creek → Cedar Creek → Clark Fork River.

• Adjoiner: Borders a ~22-acre patented claim that has been actively mined ~10 years; production reported as “substantial” (owner-reported; no public ledger available).

• Nearby features: Grubstake Gulch is a mapped valley in Mineral County; regional references to “Grubstake Gulch” appear in public datasets and maps.  

2) Access, Terrain & Elevation

• Access: USFS road network (Superior RD, Lolo NF) with spur/2-track to the drainage; seasonally limited by snow and spring breakup.

• Terrain: Narrow V-shaped side gulch opening to broader lower benches near Oregon Creek. Mixed conifer forest, stable benches for staging and test pits.

• Elevation: Representative gulch floors in this belt run ~3,900–4,600 ft; ridge/aspect control creates steep local gradients with cascades and exposed bedrock—excellent natural gold traps. 

• Stream length within claim:  Based on parcel span and typical gulch sinuosity in this block, expect ~0.6–0.9 mi of intermittent/perennial channel under claim control.

Geology & Deposit Model

• Deposit type: Placer gold sourced from nearby Bitterroot Range lode veins (quartz-sulfide). Coarse gold re-concentrates in riffles, bedrock steps, inside bends, boulder shadows, and clay/hardpan contacts.

• Host material: Angular to rounded gravels/cobbles over decomposed schist, quartzite, and local granitoids.  Abundant black sands (magnetite/hematite) signal heavies.

• District confirmation: Cedar Creek/Oregon Gulch system is a recognized placer field in USGS and state summaries of productive gold areas.  

Historical Context (District-Level touchpoints)

• 1869–1890s: Cedar Creek rush; tributaries (including Oregon/nearby gulches) were productive in hand and small hydraulic work. District produced low six-figures of ounces equivalent by early 1900s (aggregate estimates).  

• Big Flat /Oregon Creek operations: Early 1900's Big Flat Mining Co. developed hydraulic plants and camp infrastructure on Oregon Creek;  camp buildings are documented in archival photos and were reused in the 1930s.  

• Dredge era (1930s): Montana Dredge & Engineering Co. (Guy “Lee” Covington) reopened Big Flat, added road access and a gasoline dredge/dragline to work channel gravels to bedrock; shovel/dredge remains are photographed by USFS/Montana History Portal.  

These district operations directly downstream/upstream of Grub Stake Gulch demonstrate the system’s capacity for commercial-scale placer—relevant to your claim’s potential.

5) Active Adjoiner (Patented 22 ac)

• Status:  Actively mined ~10 years; production substantial (owner/operator-reported).

• Implication:  Confirms a current, economic pay system contiguous to your claim boundary.  Given similar geomorphology/aspect, pay trends may extend onto Grub Stake ground (to be validated by systematic sampling).

Hydrology & Snow/Water Window

• Runoff regime: Snowmelt-dominated; freshet typically May–June, with flashy rises after convective storms.

• Water availability: Perennial/seasonal flow sufficient for gravity recovery;  plan for settling/recirc to meet turbidity rules.

• Snow references (regional, operational planning):

  • Lolo Hot Springs (4055 ft) climate normals show heavy mid-winter snowfall (e.g., Jan ~32”, Feb ~17”, Mar ~13”), tapering by April.  

  • Lolo Pass SNOTEL (5280 ft) typical peak SWE late Mar–early Apr; NRCS site 588 provides daily normals & updates for season timing.  

  • Lookout Pass (regional ridge) averages ~400–450” snowfall annually—illustrates upper-ridge loading feeding spring flows.  

Sampling & Work Plan (field-ready)

Phase 1 – Recon (hand/sluice):

• Pan/sluice every 100–150 ft along thalweg, inside bends, bedrock steps; flag positives with GPS.

Phase 2 – Systematic (mechanized test):

• Checkerboard test pits/trenches (20–30 ft spacing) across active floodplain + lower benches; log depth to bedrock, pay thickness, concentrate weight.

• Auger where trenching is limited; target false bedrock (clay/hardpan).

Phase 3 – Pilot run:

• Small mobile plant to chase pay axis longitudinally; track yards processed / recovery to set cut-off grade & scale decision.

QA/QC:  Duplicate pans, blank runs, photo log with slate (ID/depth/ft-station), chain-of-custody on assays.

Compliance & Operating Notes

• Surface: USFS – Lolo National Forest (Superior RD)

• Minerals: BLM Missoula Field Office (unpatented)

• Permits (typical):

  • BLM Notice (5 acre disturbance) or Plan of Operations (5 acres or more or sensitive work)

  • MT DEQ 318 Authorization (short-term turbidity)

  • SP-310 Stream Protection (Mineral County CD) for instream work

• Season: May–Oct (road thaw → early snow), subject to SNOTEL-indicated meltout

• Safety: Steep banks, legacy pits/tailings; wildlife (bear/elk) – standard USFS mitigations

Sources & References:

• Montana History Portal – Big Flat Mining Co. (Oregon Creek): camp buildings (pre-1910, reused 1930s) and dredge shovel remains.  

• USGS MR-96 (productive placer/lode locations in MT) – district-level confirmation.  

• Regional snow/water planning: WRCC Lolo Hot Springs monthly snowfall normals; NRCS Lolo Pass SNOTEL site; Lookout Pass snowfall stats.  

• Mapping: Mapcarta/Wikidata locators for Grubstake Gulch.  

• Local/district history features:  Mineral County press & summaries of Cedar Creek boom.