Grain Size Analysis (Sieve + Hydrometer) for North Bay Ontario Projects

North Bay's development along the Canadian Shield margin created a unique geotechnical fingerprint—where the retreat of the Laurentide Ice Sheet dumped a chaotic mix of glacial till, varved silts, and pockets of glaciolacustrine clay across what is now the city's residential and industrial zones. Highway 11/17 corridors cut straight through these deposits, and anyone who's drilled near Trout Lake knows the material changes every few meters. A standard grain size analysis combining mechanical sieving with hydrometer sedimentation reads this stratigraphy in precise percentages—gravel, sand, silt, and clay fractions that dictate everything from frost susceptibility under Nipissing District winters to permeability assumptions for stormwater infiltration. Our Ontario-accredited lab runs the full ASTM D422/D7928 suite, delivering gradation curves that engineers rely on for seismic microzonation assessments and foundation drain design in the city's silty-clay neighborhoods.

A single hydrometer reading can reclassify a soil from silty sand to sandy silt—and that distinction changes the entire drainage design for a North Bay foundation.

Our service areas

Process and scope

We recently processed samples from a commercial development off Lakeshore Drive where the contractor hit a lens of fine sandy silt at 3 meters—material that looked uniform in the split spoon but classified as borderline frost-susceptible under the Ministry of Transportation's gradation criteria once the hydrometer results came back. That's the value of running both sieve and sedimentation on the same specimen. The coarse fraction goes through our stack from 75 mm down to 75 µm, while the minus-200 material gets dispersed in sodium hexametaphosphate and timed per Stoke's Law to capture the full silt-clay boundary. For projects near the escarpment where slope stability governs the design, the fines content and D10/D30/D60 values from this test feed directly into drainage layer specifications and filter compatibility checks against the native till.

Grain Size Analysis (Sieve + Hydrometer) for North Bay Ontario Projects — Technical reference — North Bay Ontario

Site-specific factors

North Bay's subsurface is dominated by glaciofluvial sand and gravel overlying the Precambrian Shield, but the real headache lies in the glaciolacustrine silts and clays deposited in paleo-lake basins—particularly the low-lying areas between the escarpment and Lake Nipissing. These fine-grained deposits often contain 40-60% silt with clay fractions that swell moderately when wetted. Without a full hydrometer analysis, a silty sand can be mistakenly classified as clean sand, leading to undersized drainage systems that clog within two freeze-thaw cycles. The Ontario Building Code references gradation limits for frost-susceptible soils, and missing that threshold because someone skipped the sedimentation portion of the test has caused heave damage in shallow footings across the region. The grain size curve also feeds directly into the NBCC seismic site classification—where fine-grained soils with low Vs30 can push a site from Class C to Class D, amplifying design spectral accelerations.

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Applicable standards

ASTM D422 – Standard Test Method for Particle-Size Analysis of Soils, ASTM D7928 – Standard Test Method for Particle-Size Distribution (Sedimentation), ASTM D2487 – Classification of Soils for Engineering Purposes (USCS), Ontario Building Code (OBC) – Frost Protection and Site Class Provisions, MTO LS-702 – Grain Size Analysis (Provincial highways reference)

Reference parameters

Parameter	Typical value
Test Standard (Combined Method)	ASTM D422 / ASTM D7928
Coarse Sieve Range	75 mm to 4.75 mm (3" to No. 4)
Fine Sieve Range	4.75 mm to 0.075 mm (No. 4 to No. 200)
Hydrometer Sedimentation	0.075 mm to ~0.001 mm (clay fraction)
Dispersing Agent	Sodium hexametaphosphate (Calgon)
Minimum Sample Mass	500 g (sandy); 200 g (fine-grained)
Reported Coefficients	Cu, Cc, D10, D30, D60, %Gravel/Sand/Silt/Clay

Quick answers

What is the typical cost for a sieve and hydrometer analysis on a North Bay soil sample?

For projects in the North Bay area, a combined sieve and hydrometer analysis typically runs between CA$150 and CA$250 per sample, depending on the number of size fractions requested and whether rush reporting is needed. Samples with high organic content requiring pretreatment may fall at the upper end of that range.

Why do I need the hydrometer portion if I already have the sieve results?

The sieve analysis only characterizes particles down to 75 µm (the No. 200 sieve). Everything finer—silt and clay—passes through and gets reported as a single 'fines' percentage. The hydrometer separates that fraction into silt and clay boundaries, which is critical for frost susceptibility classification, permeability estimates, and Atterberg limits correlation in North Bay's glaciolacustrine silts.

How does grain size data affect seismic site classification under the NBCC?

The NBCC seismic provisions use shear wave velocity (Vs30) and soil type to assign site classes. Fine-grained soils with high clay content often correlate with lower Vs30 values, which can shift a site from Class C to Class D or E. The grain size distribution—particularly the clay fraction from hydrometer analysis—provides supporting evidence for the assigned site class when shear wave data is borderline.

Location and service area

We serve projects in North Bay Ontario and surrounding areas.

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