“A product line within the Mincon Group”

1. Technically Speaking “A product line within the Mincon Group”

2. Elements of a Rotary Bit Rock Breakage Drilling Parameters Drill Bits Drilling Problems Bit Selection Dull Grade Analysis Troubleshooting Back to start

3. Elements of a Rotary Bit

4. Elements of a Rotary Bit Bit Features • 9 inch (229 mm) • 9 7/8 inch (250 mm) • 10 5/8 inch (270 mm) • 12 1/4 inch (311 mm) • 13 3/4 inch (350 mm) • 15 inch (381 mm) • 16 inch (406 mm)

5. Cones Tungsten Carbide Inserts – Which are pressed into the softer steel material with interference fit to hold them in place. Cone Thrust Button – Made of a wear resistant material use to take axial bearing loads. Outer Cone Shell – Insert land’s and cone grooves. Cone Bore – Internal ball and roller bearing races. Cones make up the cutting elements of the rock bit and comprises of the following: Carbide Insert Rows Nose Inner Next to Gage Gage Gage Bevel

6. Lugs

7. Inserts The Conical insert is used primarily in Medium/Medium- Hard rock.. The Ogive insert is used in areas were the aggressiveness of the conical insert is required with additional toughness. The Chisel insert is used in Soft/Medium-Soft rock. It is the standard insert in soft bits.

8. Inserts The Super-Scoop is used in very soft rock. With the patented offset tip, digging and gouging help penetrate in sticky materials. The Trimmer. It enhances the gage rows ability to cut the bore hole wall. Soft to Medium brittle rock formations. The Ovoid is use in the hardest formations. Its blunt geometry gives it the most fracture resistant design.

9. The IADC (International Association of Drilling Contractors) Code is a three numbered system to classify the hardness and type for all roller cone rock bits. First Digit – Identifies the Bit Type and Major Hardness class: 1 – Steel Tooth for soft formations 2 – Steel Tooth for medium formations 3 – Steel Tooth for hard formations 4 – Insert for soft formations 5 – Insert for soft/medium, formations 6 – Insert for medium/hard, formations 7 – Insert for hard, formations 8 – Insert for extremely hard formations Nomenclature

10. Second Digit – Designates the Hardness Subclass of the Major Hardness class. This ranges from 1 to 4, where 1 is classified as the softest subclass and 4 is the hardest subclass. Third Digit – Designates the Bit’s features: 1 – Standard Roller Bearing 2 – Roller Bearing Air-Cooled* 3 – Roller Bearing with Gage Bevel Inserts 4 – Sealed Roller Bearing 5 – Sealed Roller Bearing with Gage Bevel Insets 6 – Sealed Friction Bearing 7 – Sealed Friction Bearing with Gage Bevel Inserts 8 – Directional 9 – Other/Special *All Mincon air bearing bits are classed as #2 bearing type regardless if they have gage protection inserts or not. Nomenclature

11. 4 Classifications 4, 5, 6, 7, Based on cutting structure/rock formation Tooth spacing Number of rows/teeth Compact projection Tungsten Carbide Bit Selection and Operation

12. The AP4series bits are typically characterized by large diameter widely spaced, long projection super scoop, chisel or conical inserts. This configuration promotes maximum penetration rates in softer formations that have a tendency to stick and ball up the cutting structure. Applications: Soft formations such as shale, siltstone, soft limestone and alluvial formations. Suggested Operating Parameters: Weight on Bit – 1,000 to 5,000 lb/inch of diameter. Rotation Speed – 50 to 140 RPM. AP4 Series

13. The AP5series bits are typically characterized by more densely spaced chisel or conical inserts. This configuration promotes maximum penetration rates in soft/medium formations that are fractured or have varying degrees of hardness. Applications: Soft/medium formations such as sandstone, shale, granite and some marble. Suggested Operating Parameters: Weight on Bit – 3,000 to 6,600 lb/inch of diameter. Rotation Speed – 50 to 120 RPM. AP5 Series

14. The AP6series bits are typically characterized by a more densely spaced, shorter projecting chisel, conical or ogive inserts. This configuration promotes maximum penetration rates in medium/hard formations. Applications: Medium/hard formations such as hard limestone, hard shale, basalt and quartzite. Suggested Operating Parameters: Weight on Bit – 4,000 to 7,000 lb/inch of diameter. Rotation Speed – 50 to 110 RPM. AP6 Series

15. The AP7 seriesbits are typically characterized by densely spaced, shorter projecting conical or ogive inserts with a conical or ovoid gage insert. This configuration promotes maximum penetration rates in hard formations. Applications: Hard formations such as taconite, banded iron, skarn and quartzite. Suggested Operating Parameters: Weight on Bit – 5,000 to 8,000 lb/inch of diameter. Rotation Speed – 50 to 80 RPM. AP7 Series

16. Options Elements of a Rotary Rock Bit Rock Breakage Drilling Parameters Drill Bits Drilling Problems Bit Selection Dull Grade Analysis Troubleshooting Back to start

17. Rock Breakage

18. In ALL cases, the bit’s teeth must stress the rock enough to cause the rock to fail. The rock’s mechanical properties determine the level of stress needed. Rock Properties

19. U.C.S. - Unconfined Compressive Strength - How much ”push” it takes to break a rock in a static condition. Young’s Modulus - How ”elastic” a rock is. Poisson’s Ratio - How much a rock deforms under a given pressure. Rock Properties

20. High UCS = the rock is ”hard”. Steel vs. wood. High Young’s Modulus = the rock is elastic and resists impact, bouncing back, much like a rubber ball. High Poisson’s Ratio = the rock absorbs energy without breaking. Bit teeth ”dent” the rock without forming a chip. Putty- or clay- like. Ductile. Rock Properties

21. Low UCS - RPM is primary factor in ROP. Not much bit weight needed to break rock. High UCS - WOB is the primary factor in ROP. Need to adequately push teeth into the rock to break it efficiently. Operating Bits: UCS

22. Operating Bits: UCS

23. Low Young’s Modulus (Elasticity) - Rock is elastic, and absorbs impact without breaking. The rock is ”tough”. The rock must be given time - stressed longer - to break. Needs heavier WOB at slower RPM. High Young's Modulus- Rock is ’stiff’ or brittle. Rock will need heavier WOB, but may respond to increased RPM once correct WOB is applied. Bit Operation: Elastic Modulus

24. Low Poisson’s Ratio - Rock breaks with little change in shape. The rock is more brittle. High Poisson’s Ratio- Rock deforms a lot before breaking. Can ’dent’ rock without it chipping very much. Drilling energy is absorbed. The rock is more plastic or elastic. Operating Bits: Poisson's Ratio

25. Rock Cutting, Abrasion – Very small cracks, insert grinds surface.

26. Rock Cutting, Deeper Abrasion – Deeper cracking, but does not connect. Next cone must crack rock between these teeth.

27. Rock Cutting, Spalling Starts – Enough weight applied to card rock deeper. Cracks connect. Chips will come free with air blast.

28. Rock Cutting, Deep Spalling– Cracks connecting at deeper levels. Cracks connect between teeth and between rows.

29. Rock Cutting, Over penetration – Cuttings trapped between cone shell and rock. Cannot be blown out by air blast from nozzles.

31. Options Elements of a Rotary Rock Bit Rock Breakage Drilling Parameters Drill Bits Drilling Problems Bit Selection Dull Grade Analysis Troubleshooting Back to start

32. Drilling Parameters - The effects of WOB, RPM, Air

33. WOB causes the rock to break. Bit teeth must create a sufficiently high stress level to cause the rock to fail. Low UCS rocks require low stress levels to fail. High UCS rocks require high stress levels. Low Young’s Mod requires lower stress levels. (Elastic). High Young’s Mod requires higher levels. (Non elastic). Weight on Bit – WOB

34. Low Poisson’s may require lower stress levels to form chips. (Brittle). High Poisson’s may require higher stress levels to form chips. (Ductile). Poisson’s is not directly related to UCS or Young’s. Weight on Bit – WOB (cont.)

35. RPM is required to move the cutting teeth to the next rock cutting position. The faster you move the teeth to the next position, the faster you will drill. HOWEVER If the rock resists indentation by the teeth, there will be minimal rock breakage, and ROP will not increase proportionally with higher RPM. Softer rock = higher RPM. Harder rock = lower RPM RPM

36. Maximum Cut Efficiency Maximum Cut Efficiency With rotation speed (rpm) fixed, this illustration shows the effect of weight increases on the rate of penetration. After the formation has been ”spalled” additional weight will reduce or not increase the drilling rate.

37. Maximize ROP With the bit drilling in the Spalling Phase, it is possible to increase the penetration rate by maintaining the optimum weight, while increasing the rotation speed (rpm). The amount of increase possible in the penetration rate is variable and will be determined by the experience of the driller, the capabilities of the drill, and the formation characteristics. Maximize ROP

38. Maximum Drilling Efficiency Maximum Drilling Efficiency The preceding illustrate that: SPALLING WEIGHT plus ROTATION SPEED equals PENETRATION RATE. Therefore, optimum drilling efficiency may be reached as follows: At a set RPM, determine best weight on bit – WOB – to produce maximum cut efficiency. Note: High rotary speeds do not necessarily produce high penetration rates.

39. Bailing and Chip Exit Velocity Bailing Velocity is the speed of the air going upthe hole. Settling Velocity is the speed that chips want to fall down the hole. Chip Exit Velocity is the difference between the two. It is how fast the chips travel up the hole.

40. Bailing and Chip Exit Velocity A 3/4” chip of 2.6 SG (162 #/CuFt) rock falls at 4,168 feet per minute. A Bailing Velocity of 4,000 ft./min. will NOT carry a 3/4” chip out of the hole. Chip Exit Velocity is -168 feet/min. The chip must be reground before it can come out.

41. Bailing Velocity should be 5,000-7,000 ft/min for light, dry material. Bailing Velocity should be 7,000-9,000 ft/min for heavy or wet material. Water makes cuttings stick together, making bigger, heavier pieces to bail. Bailing and Chip Exit Velocity

42. Bailing and Chip Exit Velocity Chip Exit Velocity recommendation: 1,000 feet/minute with drill pipe worn to replacement is recommended. This gives excellent bailing in all situations.

43. Bailing and Chip Exit Velocity Do not use large pipe in a small hole to increase BV: The annulus will be restricted. Chips will not pass freely. Turbulence will increase. The pressure differential between the bit and annulus will decrease. Bit and pipe erosion and bearing failure will increase.

44. Annular Clearance

45. Bailing and Chip Exit Velocity Try to use drill pipe 2-3 inches smaller than the bit if you have enough air. Try not to use pipe that is less than 1 1/2 inches smaller than the bit if you do not have good air. Keep 3/4” minimum clearance (each side) in the annulus.

46. Bit Air Pressure Increased Bit Air Pressure = increased hole bottom cleaning force. (Nozzle velocity increases as V2). increased air to bearings. (>psi = >volume). increased penetration rates. (Cleaner hole bottom = >ROP). reduced shirttail erosion. (Volume & psi = cleaner ST lip).

47. Bit Air Pressure Recommend 40-45 psi at the bit. Cab pressure will be higher, depending on system pressure losses. Bit pressure should not cause compressor intake modulation. Make sure compressors are correctly adjusted to give rated volumes at rated pressures. Check linkages, pressure regulator diaphragms, air filters. Do thorough and frequent PM’s.

48. Air requirements Sufficient volume and pressure for cooling and cleaning bearings and cuttings removal Required annular return velocity of 5000-9000ft/min depending on ground conditions Q = Cubic feet/min required to obtain 5000ft/min D = Hole Diameter d = Pipe Diameter

50. Nozzle Size Selection Selected such that pressure inside bit = 40 - 45psi. This is typically lower than cab gauge indicated pressure. Air tests necessary to calibrate.