Milled tooth mining bit

Types of Milled Tooth Mining Bits

Milled tooth bits are one of the most common tools used to drill in the mining and oil industries. There are usually three types of milled tooth mining bits based on design and use: the overshot, the bellknap, and the straight hole bit.

• The Overshot

The overshot is a-type mining milled tooth bits that use electric power to drill down into the earth. It works by using a large drum that has rope on it to lower the drilling bit down into the mining area. Usually, the size of the rope drum decides how much of the mining area can be reached with the overshot. The drilling bit is lowered vertically down into the earth to mine horizontally. This means that only a vertical space is needed to drill with an overshot.

• The Bellknap

Like the overshot, the Bellknap also uses electric power to drill into the mining area. However, its design is a bit different. It uses a drum to mine, and the size of the drum is smaller than that of the overshot. This makes the Bellknap easier to use when mining areas are large and deep. Because of its smaller drum size, more space is required to drill with a Bellknap compared to an overshot. The Bellknap is considered better when mining areas are big and deep.

• Straight Hole Drilling

Straight hole drilling is different because it uses air-powered bits instead of electric bits. It drills straight down without turning or spinning. This means that only compressed air is used to do all the drilling work. This kind of drilling is good when only a small air compressor is available to do the mining work.

Specifications and Maintenance of Milled Tooth Mining Bits

Specifications:

• Drill Bit Size: Milled tooth bits come in different sizes, which is how wide the bit head is. Mining companies select the size based on their needs. A bigger bit can make wider holes faster, but it might be heavier.
• Milled Tooth Count: Each bit has a certain number of teeth. More teeth mean more surface area for cutting, which can improve efficiency.
• Tooth Shape: Milled bit teeth are shaped like saucers or cups. Cup-shaped teeth are usually better for digging softer rocks, while disc-shaped ones work well for harder materials.
• Shank Size: The shank is the part of the bit that connects to the drill. Shank sizes vary to fit different drills. A proper fit ensures effective drilling.
• Bit Body Material: The material makeup of the body is typically made of steel; some may also have other metal alloys to ensure durability.
• Weight: Depending on the size, teeth count, and materials used, milled bits possess different weights. The weight impacts how they are used with certain drills.

Maintenance:

• Regular Inspection: Mining operators must frequently check the bits for damage. They should look for broken teeth, deformations of the body, or any other signs of wear and tear. Early detection of small issues prevents big breakdowns later. It also preserves drill accuracy.
• Clean Bit After Use: To remove debris buildup, mining personnel should carefully clean bits after each use. Cleaning prevents material accumulation from causing overheating during drilling. It also helps avoid excessive bit wear.
• Lubricate Moving Parts: Milled tooth bits have some movable components like bearings that require regular lubrication. Lubricating such parts reduces friction and prolongs useful life. It also allows for smooth, efficient operation.
• Store Properly: When not in use, bits should be preserved in clean, dry places away from corrosive elements. Proper storage protects them from environmental damage. It maintains the integrity of their cutting teeth.

Scenarios of Milled Tooth Mining Bits

The Milled Tooth Mining Bit is useful in different scenarios where very hard rocks, thick layers of asphalt, concrete, and permaf frost, among others, need to be broken and drilled. Some examples of the use cases of milled tooth bits in the mining industry and beyond include the following.

• Hard Rock Mining

In hard rock mining operations, Milled Tooth Mining Bits are ideal for drilling through dense and compact rock formations, such as basalt, granite, and quartzite. Such hard rocks can go as deep as 3000 meters or even deeper. Milled tooth bits with large diameter gauge rings and inserts can do the work. 8.5 to 17.5 cm bits work best for underground application, while 15 to 30.5 cm pieces are ideal for surface operations.

• Geothermal Wells

Geothermal energy is becoming a popular alternative to fossil fuel energy sources. Milled tooth bits are ideal for drilling wells to harness geothermal energy. These bits can go through high-temperature rock formations.

Depths can vary depending on the geography of the area, but geothermal wells are usually between 2,000 and 4,000 meters (6,500 to 13,100 feet) deep.

• Water Wells

Milled tooth bits are also widely used for water well drilling in agricultural, environmental, and municipal applications. These bits create boreholes to access groundwater. They are suitable for areas with hard rock layers that need to be penetrated to reach the water table.

Milled tooth bits create water wells of varying depths depending on the location and geological conditions. But they can drill up to 600 meters on average.

Note: Milled tooth bits are usually used to drill these three types of wells (geothermal, water, and oil) because they can go deep and have sturdy materials that can stand even harsh environmental conditions.

• Oil and Gas Exploration

Milled tooth mining bits can be used for oil and natural gas exploration. They can penetrate different geological formations to reach hydrocarbon reservoirs. They are especially good at going through very hard rocks. In some cases, they are the only type of bit that can do the work.

Oil and gas reservoir rocks are usually between 2,000 and 5,000 meters deep, depending on the geological structure of the area. To reach this depth, larger diameter milled tooth bits are often used. For example, a 30.5 cm (12-inch) mining bit can be used.

• Foundation Drilling

When heavy structural foundations have to be laid, milled tooth mining bits can drill into hard ground and rocky terrain to create stable foundation pads. These drilling tasks are common in large construction projects like bridges, towers, and dams.

Foundation drilling with milled tooth bits can reach up to 1000 meters, depending on project requirements and soil conditions.

• Tunnel Excavation

Milled tooth bits are sometimes used to excavate tunnels in very hard rock. In such situations, the mining bit can be attached to a tunnel boring machine (TBM) or a domestic drill rig. The machine or rig will then be used to drill circular holes that will later become tunnels.

The tunnels can be for transportation (such as roads or railways) or for utility purposes (such as drainage or water conveyance).

Rock tunnels can vary in length depending on the project specifications. They can be as short as a few hundred meters or as long as several kilometers. And in terms of diameter, the tunnels are usually between 2 and 4 meters.

How to choose milled tooth mining bits

When buying a Milled Tooth Bit, one has to consider a range of factors associated with its overall performance.

• Optimum weight: The performance of a roller cone bit is greatly affected by its weight. Selecting an appropriate weight for the bit is crucial, as both insufficient and excessive weights can lead to subpar performance. Insufficient weight may prevent effective formation penetration, while excessive weight could result in premature bit wear and damage.
• Grading system: The grading system utilized for roller cone bits varies based on individual manufacturers. Familiarizing oneself with the grading systems of specific manufacturers is essential when making a selection since distinct designs and attributes are denoted by different grades.
• Shoe coatings: Bits have shoe coatings that combat wear and friction to extend the life span of the bit. There are various types of shoe coat like bionic, shark skin, etc. Choose the best one for the well to be used.

Milled tooth mining bit FAQ

Q1: What is the main difference between a milled tooth bit and a TCI bit?

A1: The main difference between a milled tooth bit and a TCI bit is the tooth design. Milled tooth bits have teeth made of steel, while TCI bits have tungsten carbide inserts.

Q2: Under what circumstances should a Milled Tooth Mining Bit be used?

A2: Milled tooth bits are typically used in softer rock formations or when drilling requires good hole smoothing and cleaning.B3: What is the trend in Milled Tooth Mining Bit development?

Q3: What is the trend in Milled Tooth Mining Bit development?

A3: The trend is toward better steel alloys and bit designs to enhance the efficiency of milled tooth bits.