1. In-Pit Crushing and Conveying
In-Pit Crushing and Conveying (IPCC) refers to the use of fully mobile, semi-mobile, or fixed in-pit crushers that are connected to conveyors and spreaders (for waste) or stackers (for ore) to transport material from an open-pit mine. A key component of IPCC systems is the crushing plant.

2. Crushing in IPCC
The crusher subsystem is, based on its primary function, which is to reduce the material to a conveyable size, a central component of an in-pit crushing station. The following crusher types are used in IPCC systems.

2.1. Gyratory
This is also compression-type machine that crush material between a moving and a stationary piece of steel. The setting between the two pieces controls the output. Although the chamber is round in shape, the moving piece of steel is not meant to rotate. Instead, a wedge is driven around to create compression on one side of the chamber and discharge opening on the opposite side.

2.2. Jaw
A jaw crusher is a compression type of crusher. Material is reduced by squeezing the feed material between a moving piece of steel and a stationary piece. The discharge size is controlled by the setting or the space between those two pieces of steel. The tighter the setting, the smaller the output size and the lower the throughput capacity. As a compression crusher, jaw crushers generally produce the coarsest material because they break the rock by the natural inherent lines of weakness. Jaw crushers are an excellent primary crusher when used to prepare rock for subsequent processing stages.

2.3. Impact
An impact crusher uses mass and velocity to break down feed material. First, the feed material is reduced as it enters the crusher with the rotating blow bars or hammers in the rotor. The secondary breakage occurs as the material is accelerated into the stationary aprons or breaker plates. Impact crushers tend to be used where shape is a critical requirement and the feed material is not very abrasive. The crushing action of an impact crusher breaks a rock along natural cleavage planes, giving rise to better product quality in terms of shape.

2.4. Sizers
Sizers are crushing machines that use low-speed, high-torque shafts with large, aggressive teeth to nip and break rocks. They are designed to handle a variety of materials, including coal and oil sands, and are known for producing less fines compared to compression-based crushers. Sizers can be used in primary, secondary, tertiary, and quaternary crushing applications, with configurations that allow for the adjustment of tooth profiles and shaft centers to control product size and manage wear.

2.5. Roll
A hybrid crusher combines the features of both sizers and roll crushers. It typically has rotating rollers combined with impact or shear forces, which makes it versatile for different types of materials. Hybrid crushers are designed for soft to medium-hard materials like coal and overburden but can handle some harder materials as well.

2.6. Feeder breaker
A feeder breaker is a type of crusher used in mining operations, primarily in coal mines. It combines feeding and crushing functions, breaking large lumps of raw material while feeding it into a conveyor system. It's commonly used for softer materials like coal or overburden and has a horizontal crushing configuration.

3. Analysis of crushers application in IPCC
A survey by Ritter revealed that 447 in-pit crusher stations have been installed since 1956. The data were provided by leading IPCC equipment manufacturers. Figure 1 shows the distribution of different crusher by type. As seen in Figure 1, based on our analysis of Ritter's thesis data, it can be seen Impact crusher was used the most in IPCC systems and Hybrid crusher was the least used.

 
Figure 1. Distribution of different crusher by type

The Figure 2 shows how Sizer and Gyratory crushers are used in In-Pit Crushing and Conveying (IPCC) systems, depending on the material being removed. Sizer crushers are mainly used for softer materials like overburden and limestone, and they are also common in coal and chalk. For example, 22 Sizer units are used for coal overburden. On the other hand, Gyratory crushers are used more for harder materials like copper, iron. Gyratory crushers are most commonly used in copper ore (38 units) and iron ore (17 units). Overall, Sizers are better for softer materials, while Gyratories are better for harder materials.

 
Figure 2. The application of Sizer and Gyratory in IPCC systems according to the type of transported material

Principles and experiences that are valid for the selection of crushers in primary stations can also be applied for IPCC units. However, attention is required for the selection of crushers with regard to the overall concept of in-pit crushers. Factors such as service weight, design dimensions, and resulting dynamic stresses should be taken into account. As well as The following general criteria need to be considered for the crusher selection:  
- Material properties:
o    density, moisture, hardness, stickiness, abrasiveness
- Application requirements:
o    feed size, product size, product size distribution, content of fines, capacity
According to various references, including the SME handbook and the experiences of the Mineser team in the field of crushing, a comparison between Sizer and Gyratory is given in table 1, where the number of dots denotes the suitability of different crusher types in relation to feed and performance characteristics. For each type of material, table 1 can be used to choose a crusher; for example, for copper, which is a very abrasive material, type Sizer is not a suitable option in terms of the abrasiveness parameter.

Table 1. Parameters required to crusher selection