Greenstone and sedimentary formations like mudstone and conglomerate, while variable, are typically low in Moh’s hardness. Moving into the actual ore zone, the formation consists of various types of rock such as feldspar, muscovite schist, and fragmental biotite, introducing abrasiveness related to the rock’s quartz content.

The challenge in softer abrasive formations is to pick a diamond drilling bit tough enough to get good life without sacrificing penetration rate.

Adding in the drive for productivity creates an additional challenge. The driller cannot simply pick the toughest bit available; life needs to be increased while still maximizing penetration rate or tripping out rods to change bits impacts overall productivity.

Using patented technology, the new Longyear Bits have diamonds that are chemically bonded to the matrix creating a more versatile, faster penetrating, and a longer-lived bit. All drillers from the newly promoted to the seasoned veteran find the color-coded Longyear Diamond Bits considerably more effective in obtaining higher productivity. For each hardness rating on Mohs hardness scale, Boart Longyear has created a recommended color. The complete line of Longyear Diamond Bits includes a Red, Orange, Yellow, Green, Blue, and Purple Bit.

Originally, Alpha series 08 and 09 were chosen in Stage3 to get a good combination of life and penetration rate. These bits, while achieving acceptable penetration rates, fell significantly short on life at 43m, the average over three months. In looking at the Longyear Bit series cross reference chart, Alpha series 08 and 09 would be replaced by the Longyear Green bit. Given the low hardness of the formation, the Longyear Blue bit was also selected to determine the best solution. In stark contrast, to the Alpha series bits, the penetration rate and bit life both increased. Using a combination of the Longyear Blue and Green bits, driller’s averaged 109 meters per bit and increased penetration rate. When drilling softer formations at site, the drillers used the Blue bit and found this bit to be incomparable when looking at the production rates and bit life. The two formulas combined yielded a 60% improvement in life and an 8% increase in productivity.

Boart Longyear Canada East Coring Supervisor, Jeremy Dykstra said, “In the beginning, we struggled to meet our production targets due to slower penetration rates and poor bit life. Once we started to trial the new Longyear Diamond Bits, the performance improvement was noticed immediately with all crews at site. Smoother cutting of the formations and longer bit life helped push us towards the successful and safe production shifts we aimed to have both for our client and our business.”

Established in 1890, Boart Longyear is the world’s leading provider of drilling services, drilling equipment and performance tooling for mining and drilling companies.

The Global Drilling Services division operates for a diverse mining customer base spanning a wide range of commodities, including copper, gold, nickel, zinc, uranium, and other metals and minerals. The Global Products division designs, manufactures and sells drilling equipment, performance tooling, down-hole instrumentation and parts and services.

Ready to take the Longyear Bit challenge? Contact your Boart Longyear representative today to order trial bits and download this blank bit log sheet to keep track of bit performance so you can compare the productivity and speed of both your current diamond bits and Longyear Bits.

Drill Crews Experience a 300% Increase in bit life

At a nickel mine in Manitoba, Canada, Boart Longyear Drilling Services field tested the new Stage 3 25mm diamond coring bit in a multi-site deployment. Drill crews experienced bit life gains of up to 300% over their previous standard 12mm crown.

Boart Longyear Drilling Services has employed 12mm bits for more than three years at a nickel mine in Manitoba, Canada. The ground conditions are demanding due to the variability in the formation, not only from one part of the mine to the other, but even within a single hole. Formations in Manitoba are typically hard abrasive quartz mixed with medium hard and coarse ground.

Until recently, the 12mm 08ABR formula had proven to be the best bit in use at the mine with an average bit life of 37.5 meters.

Extending Bit Life in Hard, Abrasive Ground Conditions

With the proven performance of the 12mm crown, the drilling crews were unsure about trying the new 25mm Stage 3. Boart Longyear field engineers knew that upgrading to the Stage 3 would provide a significant performance increase. Engineers delivered the bits to the drill crews in the 08ABR formula.

Bit Life is More Than Three Times as Effective

After putting the bits to the test, the drill crews were stunned by the 25mm Stage 3 results. The average bit life of the Stage 3 was 120 meters—more than three times the life of the 12mm crown.

As more Stage 3 bits are deployed in the field, the results continues to prove what drillers and mine operators are saying: “Boart Longyear has delivered another industry first.”