Our high-purity sodium bentonite fines in a convenient 1.2 tonne FIBC (Flexible Intermediate Bulk Container) bulk bag. Sourced directly from Australian mines.

The 1.2 tonne bulk bag is the most cost-effective way to purchase bentonite for medium to large farm dam sealing projects, effluent pond lining, landfill containment, and commercial earthworks applications.

Calculated coverage: At Bentonite Pro’s recommended application rate of 30 kg/m², one 1.2 tonne bulk bag provides material for 40 m² before any allowance. This is an ordering calculation, not a guarantee of sealing. Confirm soil suitability, the cause of leakage and the installation method before treatment. See How It Works for method guidance and limitations.

Bentonite bulk bags at a glance

Item	Detail
Bag size	1.2 tonne (1,200 kg) FIBC bulk bag with lifting loops
Product	Sodium bentonite fines, nominal particle size under 1.25 mm
Price per tonne	$295 + GST, before freight
Price per 1.2 tonne bag	$354 + GST ($389.40 including GST)
Coverage per bag	40 m² at the recommended 30 kg/m²
Delivery	Road freight to NSW, VIC and QLD addresses, confirmed before the order is accepted
Unloading	Forklift or telehandler required on site
25 kg bags	Not sold. Bentonite Pro supplies bulk bags only

How many bentonite bags do I need?

Multiply the area you will treat, including the floor and sloping walls, by the recommended 30 kg/m², then divide by 1,200 kg and round up to whole bags.

Area to treat	Bentonite at 30 kg/m²	Bulk bags	Product cost ex GST
100 m²	3.0 tonnes	3	$1,062
250 m²	7.5 tonnes	7	$2,478
500 m²	15.0 tonnes	13	$4,602
1,000 m²	30.0 tonnes	25	$8,850
2,000 m²	60.0 tonnes	50	$17,700

Use the bentonite quantity calculator for your own area, and the transport calculator for an indicative freight estimate.

Bentonite bags: common questions

How much does a bag of bentonite weigh?

Each Bentonite Pro bulk bag holds 1,200 kg (1.2 tonnes) of sodium bentonite fines. Retail bentonite is also sold in 25 kg bags, which take 48 bags to make up the same 1.2 tonnes.

Are bulk bags cheaper than 25 kg bentonite bags?

Yes, per tonne of material. Bentonite Pro charges $295 a tonne before GST and freight. Retail 25 kg bags listed online in October 2026 cost about $640 to $1,000 a tonne before freight.

How are bentonite bulk bags delivered?

Bulk bags travel by road freight to NSW, VIC and QLD addresses. Freight is calculated to your delivery address and confirmed before an order is accepted. You need a forklift or telehandler and safe truck access to unload them.

Where to buy sodium bentonite for dams

Bentonite Pro sells sodium bentonite fines direct in 1.2 tonne bulk bags for farm dams, ponds and earthworks across NSW, VIC and QLD. Bentonite Pro charges $295 + GST per tonne, so each bag is $354 + GST before freight. Retail 25 kg bags listed online in October 2026 cost about $640 to $1,000 a tonne before freight, so bulk bags suit dam-scale jobs. The sodium bentonite delivered price guide sets out the price per tonne, coverage per bag and how freight to your address is calculated.

Read before you order

Need the leak diagnosed or the treatment installed rather than material alone? Our parent company, the Big Ditch Dam Building Company, inspects and repairs farm dams.

Typical physical properties

As-is basis, from the Big Ditch Bentonite spec sheet.

Montmorillonite content: >90%
Cation exchange capacity: >90 meq/100 g
Swell index: 7 to 16 mL/2 g
pH: 5 to 7.5
Moisture content: 12 to 20%
Bulk density: 1.2 to 1.4 t/m³

Fine-grade particle size

Nominal particle size: <1.25 mm
Upper limit tolerance: retained on 2 mm, 5% maximum by weight
Lower limit tolerance: passing 75 µm, 15% maximum by weight

Typical chemical properties

Oven-dried basis (105°C), XRF.

Silica (SiO₂): 61.5%
Alumina (Al₂O₃): 18.5%
Soda (Na₂O): 1.3%
Magnesia (MgO): 5.2%
Lime (CaO): 0.1%
Potash (K₂O): 1.3%
Ferric oxide (Fe₂O₃): 4.1%

These are typical values for general information, not guaranteed specifications. View the Big Ditch Bentonite spec sheet (PDF) for the full technical information and disclaimer.

Country of origin: Australia
Packaging: 1.2 tonne FIBC bulk bag with lifting loops

Freight note: Bulk bags are delivered by road freight. Forklift or telehandler required for unloading. Please ensure site access before ordering. Contact us for freight quotes to remote areas.

dam sealing bulk

Sodium Bentonite Bulk Bag, 1.2 Tonne (FIBC)