Stemming plugs are a cost-effective way to ensure that blast energy focuses into rock, and not into the atmosphere. Placed at the top of the explosive column, they hold the stemming material in place as the charge fires, delaying the moment the hole vents and keeping high-pressure gas working in the rock for longer. Done well, that means better fragmentation, less flyrock and airblast, and more value recovered from every hole.
We compare two options. Varistem, a field-proven plug with published data, and EasyTamp, a low-cost LDPE plug from South Africa’s Plastic Innovations. We assess each on cost, hole-diameter range, explosive compatibility, mechanism, and results, and where a manufacturer does not publish a figure, that gap is stated rather than assumed.
Varistem is priced by hole diameter, from about US$1 for the smallest sizes to US$16.13 for the largest. You buy only the size a given hole calls for, so spend tracks the pattern instead of over-specifying every hole.
The pricing is public so it can be costed accurately while the blast is still on paper, and framed against ROI, since the plug cost is small next to the drilling and explosive savings it targets.
No per-unit price is published. It is sold on quote for bulk and custom orders. The company names Takealot and Makro as sales channels, but neither lists EasyTamp as of August 2026. No verifiable figure exists without a direct quote.
Both compete at the low-cost end. Varistem publishes diameter-based pricing of approximately US$1 to $16 with documented ROI. EasyTamp’s price is quote-only with no cost-benefit data. Its value case cannot be verified.
A defined range covering all diameters from 1.75″ (45mm) to 10″ (251mm), with diameter-specific plugs that let engineers match the plug tightly to the hole.
Each size also tolerates the real-world variation in hole diameter that comes from drill-bit wear and resharpening. Holes can drift a few per cent off nominal, expanding to fill a slightly oversized hole while still passing into one at the smaller end of tolerance. That combination of a wide catalogue and per-size fit is what lets Varistem maintain consistent confinement across varied ground conditions and drilling patterns.
Plastic Innovations does not publish a hole-diameter range, stating only that EasyTamp “accommodates a wide range of hole sizes.” Its multi-tiered, flexible finned form appears designed to seat across a band of bore sizes rather than one exact diameter. Comparison with similar collar plugs suggests a usable band of roughly 1″ to 6″ (25 to 150mm), but without a manufacturer specification, this remains an estimate.
Varistem has a verifiable range (1.75″ to 10″) with diameter-specific fit. EasyTamp gives a general claim and an estimated 1″ to 6″ band, unconfirmed at larger diameters.
For any operation running holes above roughly 6″, or one that needs a documented fit for its specific bore, Varistem is the safer choice.
Compatible with all common agents (ANFO, emulsion, water gel, heavy ANFO): ANFO for dry holes, emulsion/water gel/heavy ANFO for damp or flooded holes. Also suited to air-decking.
The real advantage is standardisation. One plug type spans every standard explosive and doubles as an air-deck plug; an operation can run a single consumable across dry, wet, and air-decked holes, simplifying inventory and letting engineers change charge designs without changing plugs.
As a chemically stable LDPE plug, it acts as an inert mechanical barrier and does not interact with the charge over its short in-hole service life, making it broadly compatible with standard agents (ANFO, emulsions, water gels, slurries, heavy ANFO, packaged explosives). Its water-insoluble build suits wet holes. Plug selection is driven by hole diameter and condition.
Both work with all standard explosives. Varistem publishes its compatibility with clear dry/wet guidance and confirmed air-decking use, so it can be specified straight from the datasheet.
EasyTamp’s compatibility is a fair inference from its inert LDPE build but is unstated, with no guidance on charge type or hole condition, so it’s best confirmed before it enters a charge plan. Even on compatibility, documented assurance favours Varistem.
Dip-moulded for a flexible, high-tear-strength body. On firing, the shockwave drives the plug up into the stemming, forming a temporary dynamic pressure seal that channels energy into rock microfractures before the plug fails, improving fragmentation and energy use.
A flexible LDPE plug that seats in the collar by friction fit, placed with its companion Easy Applicator Stick. It holds the stemming column to resist ejection and delay gas venting, keeping energy in the rock for longer. No specific pressure-sealing mechanism is described beyond this retention function.
Both retain the stemming column, but the mechanisms differ. EasyTamp’s stacked, flexible flared skirts seat by pressing against the borehole wall, a passive interference (friction) fit evident from the product’s design. Plastic Innovations does not describe the mechanism in these terms or publish retention data, so this reflects the visible geometry rather than a stated specification.
Varistem’s dynamic seal goes further, driving the plug into the stemming on firing to form a pressure seal that channels energy into rock microfractures, the mechanism behind its fragmentation gains. EasyTamp provides retention. Varistem provides engineered, evidence-backed confinement.
Varistem offers extensive field data, including reports of up to 25% better fragmentation, 10%+ pattern expansion for equal fragmentation, up to 80% less flyrock, 87% better cast, 14%+ higher crusher throughput, and 8% quicker loading. Site ROI includes over US$10M/year in added value and an 11% advance uplift at an underground platinum mine.
No quantified results, case studies, or trial data are published. Claims are qualitative only. The one supported point is water performance. The water-insoluble LDPE will not degrade in wet holes, though no wet-hole sealing data is published.
The clearest difference. Varistem backs its claims with measurable, site-referenced data. No performance data for EasyTamp is published by Plastic Innovations or by any independent source.
A review of the manufacturer’s channels found only qualitative marketing claims and no fragmentation, throughput, or field-trial results. By contrast, Varistem’s performance is documented in both vendor and independent studies.
Choose Varistem when performance, precision, and documented ROI matter. Its 1.75″ to 10″ range, high-pressure seal, air-decking support, and published field data let engineers justify the spend against fragmentation and throughput gains.
It fits best in operations where blast outcomes are measured and costed. If you track fragmentation, dig rates, crusher throughput, or cost per tonne, Varistem gives you a plug you can trial, benchmark, and defend with numbers rather than assurances.
It also suits operations answerable to a business case or ROI target, and anyone standardising on one proven consumable across dry, wet, and air-decked holes.
Choose EasyTamp when local supply and simplicity outweigh published performance. Made in Johannesburg, it offers fast regional supply, easy handling, wet-hole suitability, colour-coded variants for site management, and custom or bulk runs.
EasyTamp is a simple, locally made product with practical strengths but largely unpublished specs and performance. Varistem is an engineered product with a defined size range, an active seal mechanism, explicit compatibility, transparent pricing, and quantified results.
The two barely compete on the same terms. EasyTamp sells on availability and price, with fit and value confirmed on site; Varistem sells on evidence, with a diameter-matched fit, dynamic seal, air-decking, and published data you can cost before buying.
So the choice comes down to what you need to justify. If it’s a locally supported plug, EasyTamp can work. Varistem is clearly stronger for any operation building a business case around blast performance.
Introduction and Project Background ERG Industrial conducted a Varistem® stemming plug pilot project at a South African underground platinum mine between May 2024 and June
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