The efficient handling of dense, bulky and hazardous materials is a basic element of mining. The packaging used to store and move these valuable commodities, such as iron ore fines and coal to chemicals and platinum group metals (PGMs), must deliver structural integrity, environmental containment and safety for workers.
Custom Bulk Bags (CBB) and its sister company, Integrated Polypropylene Products (IPP), have become some of the best producers of high-quality bulk bags for mines in South Africa and the region. CBB and IPP are divisions of Custom Extrusion Pty Ltd (CE). These packaging products, also referred to as flexible intermediate bulk containers (FIBCs), are designed specifically for the mining and mineral processing industry.
We can produce up to 3.5 million bulk bags annually. These are capable of lifting Safe Working Loads (SWL) from 500kg to 2000kg per bag. We are also a Level 1 B-BBEE supplier that falls under the ownership structure of Deneb Investments Limited.
Mining FIBCs and industrial applications
For mineral ores with high density, we can supply heavy-duty single-trip and multi-trip bulk bags made of high-GSM woven fabric to withstand the outward pressure caused by dense minerals, concentrates, ores and chemicals. We also equip our bags with triple sift-proof seams with special filler cords and with built-in polyethylene (PE) or aluminium foil liners to prevent dust and moisture ingress for fine or hazardous concentrates, such as vanadium or chemical reagents.
UN-approved designs provide safe containment for dangerous goods and reactive chemicals, from smelting to leaching, and ventilated bulk bags are available for moisture-releasing commodities. In addition to bulk storage, woven bags can also be used for backfill containment, erosion control and weeping bags in underground mining.
Polypropylene suitability, processing and testing for mining
We choose high-quality polypropylene (PP) as the basis for all of our mining bulk bags. This is because PP is a non-reactive polymer that can withstand harsh chemicals and a fair amount of abuse. PP has an excellent strength-to-weight ratio, structural flexibility and high chemical resistance. It is also inert to most alkalis, acids and organic solvents normally found in mine tailings or process reagents.
During extrusion, the PP resin is treated with premium ultraviolet (UV) stabilisers to withstand the harsh conditions of African mining sites, such as high solar exposure in the Northern Cape. This ensures no photo-degradation and embrittlement affect the bags when they are placed outdoors. The fabric is also subjected to commission lamination (extrusion coating with PP or LDPE blends) to increase resistance to abrasion, tearing and moisture penetration.
These materials are put through rigorous mechanical testing before passing batches. This process includes checking the tensile strength of the PP tape, burst tests on the fabric, seam pull tests and dynamic top-lift stress tests to confirm performance under extreme operational loads.
Ratings, certifications, and industry standards
Bulk bags for use in mining need to adhere to strict safety and quality standards. Both CBB and IPP have quality management certifications ISO 9001:2015, which means that the production process from raw polymer to the finished container is standardised.
Bags conform to international standards, like ISO 21898, which governs the design and safety performance of FIBCs. All bags are designed to a proven Safety Factor (SF) of at least 5:1 for single trip bags and 6:1 for reusable or heavy mineral containers. One real-world use case of our 5:1 single trip bulk bags is the 2000kg units supplied to Minrite. These bags, along with others, are specialised UN-certified FIBCs tested for drop impact, stacking stability and tear resistance.
Synergistic roles: The IPP and CE ecosystem
The seamless manufacturing process is made possible by the complementary roles of IPP and CBB, under the Deneb Investments umbrella. The upstream extrusion and production of woven fabric, and the downstream manufacturing of bulk bags and other woven products, are handled by the companies. This ensures complete in-house production and adherence to standards and time constraints.
This full vertical integration provides significant strategic advantages to our mining clients. CE controls the entire supply chain, from raw polymer tape extrusion to final seam stitching, avoiding reliance on imported fabrics and component suppliers. This guarantees product availability and short lead times by protecting mining operations from international shipping delays, port congestion, and fluctuating exchange rates.
In addition, we can custom-engineer packaging that seamlessly integrates with a mine’s automated conveyor belts, loading chutes, and forklift rigs, thanks to direct technical control over fabric weights, weave density, loop styles, and spout shape.
Sectors covered and prospects for the future
Currently, mining and minerals, industrial chemicals, commercial agriculture and forestry, and certified food-grade processing are the four main pillars on which the two companies operate. We recently started to produce sand-filled bags for floodwater prevention and rerouting, with great success in the Western Cape.
One specific customer that we’ve had a successful long-term partnership with is Illovo Sugar Africa. We installed a refurbishing plant specifically intended to repair and refurbish the multi-trip FIBCs purchased by the sugar giant.
In the future, the world’s shift to green energy materials presents substantial growth prospects. CE is in a unique position to provide specialised, high-purity FIBCs as demand increases for South African vanadium (for grid-scale energy storage batteries), battery-grade manganese, copper, and lithium.
Two other potential prospects for the future include scaling distribution throughout Sub-Saharan Africa under the African Continental Free Trade Area (AfCFTA) and promoting environmentally friendly packaging through increased solar-powered manufacturing and 100% recyclable polypropylene solutions.
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Custom Bulk Bags is a major South African manufacturer of woven polypropylene bags for various industries, including mining, chemicals and agriculture. We are a Level 2 B-BBEE supplier that falls under the ownership structure of Deneb Investments Limited. For more information on our products, contact sales@custombulkbags.co.za.
