Drilling and mining
To exploit mines, we need mining equipment and machinery. There are several methods for extracting from the mine. Open (surface) extraction and underground extraction. The choice of any of these methods depends on the desired depth, the shape of the product and economic issues. However, most of the world’s mines, especially iron ore, are mined using open pit methods.
Conventional drilling methods in open pit mines
Drilling in different operating conditions requires different methods and equipment that are defined according to its application. The selection of drilling methods used in mines has been done for many years, and unfortunately, careful and technical study of new drilling methods to select and replace old methods is rarely done. Open mine drilling machines are divided into two general categories based on the method of transferring drilling force: rotary and impact drilling machine, which is also an impact drilling machine based on the transmission medium and the location of hammering (hammering) into two general categories: hammer out and hammer. They are divided into pits.
Rotary drilling method
It is one of the most common production drilling methods in the world’s large open pit mines. Today, most of the world’s largest open-pit metal drilling rigs are rotary. The main difference between rotary drilling method and other drilling methods is the removal of impact as a hole drilling factor from this drilling method. In this method, drilling work is done by cutting the surface of the rock and the determining factor in this method is the weight of the machine and the set of accessories of the drilling system that is transferred to the rock as a load on the drill. Therefore, rotary machines weigh much more than other drilling rigs.
Hammer drilling method
Excavation hammer drilling method
In this method, the hammer or hammer drill is placed outside the hole and transmits energy to the drill bit. This drilling method is widely used due to the high rate of permeability in the rock in suitable geological conditions. Limitations of the drilling rig that work with this method include limited diameter and limited drilling depth due to high deflection, low durability of drilling rigs and low operational efficiency in drilling in harsh geological and tectonized conditions. The advantages of this method are the initial investment cost and lower fuel consumption of this device compared to other common methods.
Hammer drilling method inside the pit
Borehole drilling method is a reliable method for drilling in easy to difficult geological conditions. In this method, the impact energy is transmitted directly to the drill bit and the energy drop in it reaches the minimum circuit. In this type of device, the shape and structure of the hammer prevents the deviation of the hole and causes more stability in the wall of the hole. Since in this drilling method, the space between the wall of the pit and the drilling rod is less than the hammer method outside the pit, therefore, the speed of drilling and flushing particles in the pit will be faster than other methods.
This method of drilling, due to the hammer being placed inside the pit, creates the least amount of deviation of the pit compared to other common methods. Other advantages of these devices are their suitability for use in unfavorable geological conditions and ease of operation for the operator of these devices.
Copard drilling method
Prior to the advent of the Cooprad drilling system, drilling holes without deviation in the shortest possible time and under unfavorable geological conditions was one of the dreams of miners. But today, Cooprad drilling machines are the best suitable option for drilling holes without deviation in unfavorable drilling conditions. This drilling system combines the advantages of both in-hole hammer drilling systems. It has a hammer outside the hole. In this drilling system, a string and a central radar are used for drilling, which are responsible for controlling the deflection of the pit and increasing the drilling speed, respectively. This drilling system includes a combination of impact rods and drilling pipes.