Considering some of the key challenges currently facing the iron-ore industry, there is a definite need for original-equipment manufacturers (OEMs) to focus on product research and development for specific customised products, says tooling, materials technology, mining and construction engineering group Sandvik rock tools business line manager Philip Smith.

He tells Mining Weekly that mining companies are no different to other companies and, in an increasingly competitive and challenging economic environment, they too must embrace efficiency improvements to protect profit margins.

“When it comes to drilling, efficiency equates to doing more with less and the trend today for mining companies is to use fewer, but more efficient, drilling machines and drilling processes.”

He adds that this change has inevitably increased the physical demand on tooling, requiring that it penetrates faster or lasts longer, or both, without compromising safety.

Adding to the normal complexity of rotary drilling, Smith highlights geological variability and the inherent hardness of iron-ore deposits as two additional key challenges facing iron-ore miners.

Continuous product development is, therefore, a key focus area for Sandvik and some of the company’s considerations include the design of rotary bits with more operational flexibility to help adapt to changes in geology and drilling characteristics within a particular site, opportunities to enhance a product’s design for better or extended bit life and a better drill-bit penetration rate.

Smith adds that, in the rotary blast-hole drilling industry, the design life of a drill bit and its penetration rate are often traded off against each other.

“However, penetration rate is currently deemed to be more critical than the life of the drill bit itself, which is entrenched in the concept of total drilling cost (TDC), which includes the capital cost of the equipment. As mines seek to become more capital-equipment efficient, they try to conduct the same amount of drilling with fewer drills,” Smith says.

He explains that, if those drills can drill 20% to 30% faster, the mines would require 20% to 30% fewer drills for the same job. Smith therefore maintains that mining companies would be willing to pay slightly more for rotary tools that provide increased drilling speed, penetration rate or extended product life.

Smith says significant research has to be invested in the manufacture of rotary drill bits to ensure that they receive an adequate amount of life and perform at an adequate penetration rate to ensure economic viability of the product and the operation.

“While Sandvik aims to improve the product life and the penetration rate, it is also focused on enhancing the design of the bit or selecting the right bit to customers’ requirements.”

Product Development
Owing to Sandvik’s significant research in product development, the group can provide three tiers of products as part of its rotary drilling bit range, Smith highlights.

“Sandvik knows exactly how the choice of a drill bit can affect the performance of a drill rig and the overall cost of business. With extremely versatile models, and different bit designs tail-ored to different types of rock, we can enhance the performance of any rig to ensure higher productivity and lower total costs,” he adds.

Products in the three tiers include the RR440 ultra-premium sealed bearing, which is used in hard-drilling applications in rock of medium to low abrasiveness. This product provides the best value when replacing an air bearing bit that typically fails with more than 50% of the cutting structure remaining, Smith notes.

“The RR440 is the premium choice for cus-tomers who want the best drill bits in the mar-ket in order to achieve the lowest possible TDC,” he says.

The RR321 premium air bearing is used for medium- to hard-cutting drilling in rock with medium abrasiveness, particularly when drilling capacity is constrained and the customers are operating rigs at the upper limits of their design capacity and cannot afford delays associated with bit change-outs.

“The RR220 is a standard air bearing, used in soft- to medium-drilling applications, particularly in rock with medium to high abrasiveness, and when the client is focused on the lowest cost per meter drilled in operationally challenging conditions,” Smith says.

Sandvik currently supplies these products to customers in the US and Canada and is testing the ultrapremium product at certain iron-ore mine sites in South Africa and Australia.

For instance, during a product trial for an iron-ore mining company, the customer required a drill bit with an increased life. “Sandvik designed a drill bit according to the client’s specifications, and a 50% to 60% improvement in drill bit life was achieved, at a slightly lower penetration rate.”

Citing another case study, Smith cites that Sandvik achieved a 30% to 40% improvement in penetration rate, with a marginally better drill bit life, for an iron-ore mining company that required a higher penetration rate for a drill bit.

The RR321 premium air bearing is currently used the most, owing to its wide range of applications, says Smith.

Service Portfolio
Smith notes that, while customers select the drilling tools that are best suited to their oper-ations, it is important that they continue to use these tools properly.

He warns that, if tools are not well looked after, customers will not reap the full benefits of the product. However, he explains that, owing to skills shortages and production pressures, customers are not always able to focus on main- taining that necessary “operational sweet spot”.

In light of this, Sandvik provides maintenance and management services, which include on-site consulting, monitoring and advising on its tools, says Smith, who adds that there has been a marked increase in the demand for these services, owing to the current skills deficit.

“However, the demand is not unique to rotary drilling tools. All drill-tool users who conduct down-the-hole and top-hammer drilling are looking to the OEMs to ensure that they reap the full benefits of the tools,” he concludes.