Tag Archives: rock

Block Caving Mining Method 101

Block Caving

 

Block caving is large-scale mining method that allows for huge volumes of rock to be extracted efficiently. However, the development time before production starts is longer compared to other mining methods. By drawing rock from the extraction level in the lower part of the mine, a gap is created. Absence of support for the overlying rock mass together with rock stress and gravity will cause the rock mass to cave.

Block cavingThis minimizes drilling and blasting of ore but requires the ore body to be large enough and the rock condition so to be favorable for natural breakage. To draw the first pieces of rock, to create this gap, the rock mass in the lower part of the ore body needs to be broken down into smaller pieces. To achieve this, an undercut level is developed and blasted. Below, an extraction level is developed where ore will be extracted throughout the life of that production area. Drawbells are created between undercut and extraction levels and become passages for caved rock. To avoid misfires, accurate drilling is crucial. Substantial rock reinforcements such as steel arches, sprayed concrete, cable bolts, rock bolts, steel mesh and straps are usually required due to several factors associated with block caving, including extreme rock stress changes and a long production period. Rock is loaded from the draw points and can be dumped into ore passes connected to a haulage level or directly to a crusher.

Block cavingA variety of transportation methods can be employed for transporting ore to the surface. The fragmentation of the ore and the crushing requirements are key factors influencing the choice of a method. The extraction of ore will sooner or later cause the surrounding rock to cave, resulting in subsidence at the surface. Provided the rock breaks successfully and the ore can be extracted evenly at desired draw points, block caving is a high productivity method with low operating costs that allows a high degree of mechanization and capability of automation.

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block caving

Sublevel Caving Mining Method

Sublevel Caving

 

Sublevel Caving is one of many different methods for underground hard rock mining. It is a large-scale mining method suitable for large ore bodies with a steep dip and a rock mass with a host rock in the hanging wall will fracture under controlled conditions. Therefore, the infrastructure is always placed on the footwall side.

 

sublevel cavingMining starts at the top of the ore body and progresses downwards in a safe sequence. Sublevel Caving is a productive mining method where all of the ore is fragmented by blasting and the host rock in the hanging wall of the ore body caves. Once the production drifts have been excavated and reinforced, the opening rays and long hole drilling and ring patterns are completed. Minimizing hole deviation when drilling is crucial as it will affect the fragmentation of the blasted ore and therefore also affect the flow of the caving rock mass. Rock is loaded from the cave front after each blasted ring. In order to control dilution of waste rock in the cave, loading a predetermined extraction percentage of rock is done. Or, if there is a significant difference in density between ore and waste rock, bucket-weighing can be utilized for dilution control. When loading from the cave front, it is important for the productivity to keep the roads maintained in a good condition.

 

Sublevel cavingDumping the ore into ore passes connected to the haulage level is an efficient way of transporting rock from the production points to the crusher. Each sublevel features a systematic layout with drifts across the ore body. Activities in the parallel production drifts are performed simultaneously in order to maintain a good process in the mine. Due to caving of waste rock into the blasted ore, a certain degree of ore loss and waste rock dilution comes with the method. Caving will, sooner or later,  also cause subsidence on the surface. Sublevel Caving is a productive large scale mining method that enables safe and efficient use of mining equipment. With good mine planning, there are also great opportunities for automation.

Watch the full video here.

Our team will be happy to explain the specifics of our patented technology, so do not hesitate to contact us at sales@newtrax.com to arrange a meeting.

 

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Sublevel Caving Mining Method