Cut and fill
It is an ascending method (enhancement). The mineral is removed by horizontal and / or vertical stripes starting at the bottom of a pit and progressing vertically. When the entire strip has been removed, the corresponding volume is filled with sterile material (filler), which serves as a working floor for the workers and at the same time allows the walls to be supported, and in some special cases the ceiling.
Characteristics of the method
The cut and fill operation can be used in deposits with the following characteristics:
- Strong dip, higher than 50º inclination. Physico-mechanical characteristics of the mineral and relatively poor box rock (incompetent rock). Moderate power. Regular limits of the deposit.
Advantage
- Recovery is close to 100%. It is highly selective, which means that you can work high-grade sections and leave those low-grade areas unexploited. It is a safe method. It can achieve a high degree of mechanization. It is suitable for deposits with incompetent physical-mechanical properties.
Disadvantages
- High operating cost Low performance due to production stoppage as a consequence of filling High consumption of fortification materials.
Scheme
Method summary
| 1. Geometry of the Deposit | Acceptable | Optimum |
| Shape | Anyone | Tabular |
| Power | Anyone | > 3m |
| Dip | > 30 ° | > 60 ° 1 |
| Size | Anyone | Anyone |
| Regularity | Anyone | Irregular |
| 2. Geotechnical Aspects | Acceptable | Optimum |
| Resistance (Ceiling) | > 30 MPa | > 50 MPa |
| Stamina (Ore) | s / depth | > 50 MPa |
| Fracturing (Roof) | High-medium | Middle-low |
| Fracturing (Ore) | Middle-low | Low |
| In-situ Tension Field (Depth) | Anyone | <1000m |
| Tense-Deformational Behavior | Elastic | Elastic |
| 3. Economic Aspects | Acceptable | Optimum |
| Unit Value of Ore | Medium-High | Tall |
| Productivity and exploitation rate | Middle-low | NA |
Chambers and pillars
The Room and Pillar method of exploitation or also chambers and pillars, consists, as its name implies, in the exploitation of large houses separated by pillars for supporting the ceiling. The recovery of the pillars can be partial or total, in the latter case, the recovery is accompanied by the controlled collapse of the roof that can be carried out together with the exploitation or at the end of the life of the site, logically the roof collapse in this case is fully controlled.
Field of application of the method
This method of exploitation is widely applied and has developed quite a bit in recent years, due to its low cost of exploitation and at the same time allowing moderately selective exploitation to a certain extent. The deposits that are best presented for exploitation by Room and Pillar are those that have a low manteo angle, although it is also applicable in manteo deposits between 30 ° and 40 °, that is, in critical manteo deposits, where the ore cannot drain by gravity.
Advantage
- The method is to a certain extent selective, that is, poorer areas may not be exploited without greatly affecting the applicability of the method. In large deposits, complete mechanization can be achieved, which greatly reduces operating costs. all the development and preparation can be done by mineral, or otherwise the developments by waste can be very insignificant. It allows the exploitation without problems of mineralized bodies located parallel and separated by sterile zones. The recovery of the deposit not even being 100 % can reach satisfactory recoveries of the order of 80 to 90%.
Disadvantages
- If the deposit presents a very irregular mineralization, both in run and in power, it could affect exploitation, greatly limiting the planning of the method, as well as drilling and causing loading problems, especially for possible mechanizations., when the manteo is very close to the critical manteo (45 °), problems occur for the movement of the mineral in the mansions and this problem is even more serious, in the case of narrow mantles. In the case of powerful mantles there are problems in the mechanization of the drilling, which results in mobility difficulties when using heavy drilling equipment. Dilution of the law: it is a problem that is very important and that in cases of weak ceilings can be cause that limits the application of the method.
Scheme
Method summary
| 1. Geometry of the Deposit | Acceptable | optimum |
| Power | > 1 m | > 3m |
| Dip | <30 ° | Horizontal |
| Size | Anyone | Anyone |
| Regularity | ||
| 2. Geotechnical Aspects | Acceptable | Optimum |
| Resistance (Ceiling) | > 300 k / cm2 | > 500 k / cm2 |
| Stamina (Ore) | s / depth | > 500 k / cm2 |
| Fracturing (Roof) | Low | Very low |
| In-situ Tension Field (Depth) | <1000m | <600m |
| Tense-Deformational Behavior | Elastic | Elastic |
| 3. Economic Aspects | Acceptable | Optimum |
| Unit Value of Ore | Low | NA |
| Productivity and exploitation rate | Tall | NA |
