In the hard rock mines of the Appalachian Mountains, I often sit beside the tunnel boring machine, watching the cutting teeth—after 11 years as a field consultant for mining tools in the US, the most frequent question miners ask is: “Which tooth, Pyramid or Conical PDC, will reduce downtime?” Last week, at a shale-granite mixed mine in Pennsylvania, I installedPyramid PDC Inserts and Conical PDC Inserts from Wuhan Ninestones Superabrasives Co., Ltd. on the same machine and conducted a 96-hour continuous operation test. The performance of the two teeth clearly outlined the choice for US mines.

Structure Decides: The Spiral Rock-Breaking Logic of the Pyramid PDC Insert

The “working ability” of the PDC tooth lies entirely in its structure. The Conical PDC Insert, with its dome-shaped cone design, disperses impact and is suitable for homogeneous soft rock. However, the Pyramid PDC Insert, with its four-sided pointed design, has only one-third the contact area with the rock layer compared to the conical teeth, directly doubling the pressure when biting into hard rock. In tests, against granite with a density of 2.9 g/cm³, the Pyramid PDC Insert cut 18% faster than the conical teeth. The pointed tip can also get stuck in tiny cracks in the rock layer, unlike the dome which “slips and spins.” This is a “key to breaking rock” for dense rock formations like those in the Appalachian region.

 Customized Adaptation for Mining Scenarios: The High-Load Advantage of the Pyramid PDC Insert

The strata in American mining areas are never a “single formula”—in Montana’s metal mines, shale and quartz veins are mixed together, requiring the cutting teeth to alternate between biting into soft layers and resisting hard particles. In tests, the pointed tip of the Pyramid PDC Insert accurately penetrated the quartz vein interlayer without being chipped or broken by hard points. After 6 hours of continuous operation, the diamond layer of the Pyramid PDC Insert showed only slight wear, while the conical teeth had already developed three chips, requiring shutdown and replacement. For mining areas with such complex strata, the Pyramid PDC Insert’s “resilience” is clearly superior in withstanding high loads.

 Cost Analysis of US Mines: The Long-Term Benefits of Pyramid PDC Inserts

US mine owners prioritize “practical cost-benefit analysis”: A coal mine in Texas previously required replacing the cutting teeth 8 times a month when using conical teeth, resulting in 350 tons of coal lost due to downtime. After switching to Pyramid PDC Inserts, the average number of tooth replacements per month dropped to 3, reducing lost working hours by 65%. Considering the difference in the unit price of the teeth, the overall monthly cost actually decreased by 25%. This is the benefit of “fewer tooth replacements, more work”—if your mine is also struggling with hard rock and interlayers, the pointed design of the Pyramid PDC Insert can help you tackle these tough challenges.

For comparison of the specific specifications of the Pyramid PDC Insert and Conical PDC Insert, or to customize a model suitable for US mines, please contact us through the following methods:

- Phone: +86 17791389758

- Official Email: jeff@cnpdccutter.com

- Product details can be found on the official website: https://www.cnpdccutter.com/

About the author: Mark Harris, from Ohio, USA, has 11 years of experience as a field technical consultant for mining drill bits and cutting tools. He travels extensively in Appalachian and Midwestern mines, specializing in field adaptation and cost optimization solutions for mining tools, and has provided tool selection guidance to more than 20 US mines.