As we all know, ore resource is kind of exhaustibility and non- renewable mineral resource. In order to improve the use ratio of ore resource to recycle the low-grade ore in the cutoff grade edge play an important role in improve the use ratio of ore resource. The ore deposit of Meiziwo mine lot is igneous rock postmetamorphism high temperature hydrothermal fissure filling, quartz-vein type wolframite deposit. The high-grade tungsten ore in Meiziwo rich ore worked out and the storage content high grade tungsten ore it is lesser. But the production capacity of Meiziwo is still high, so in order to increase the service year of Meiziwo tungsten ore and improve use ratio of ore Meiziwo has employed recovering low-grade resource.
The mining technology of Meiziwo low grade tungsten ore recovering project is shallow-hole shrinkage mining. The concrete practices are as follow: to set gangue funnel at the both ends stope and ore caving uses secondary ore caving. The first time ore caving make barren rock fall down. And the second time ore caving the aim is gangue. Finally, putting the gangue in the gangue funnel and then take it out. Secondary ore caving not only can separate the barren rock and gangue rock but also reduce the rate of dilution of Meiziwo and improve the ore extracting ratio in mining. After take gangue out should employ diagrid by ore pass or dressing plant. So it can decrease the dilution rate and can reduce freight volume and mineral processing volume.
According to statistics, Meiziwo low-grade tungsten ore recovering ore-extracting ratio in mining is 93%, 91% of dilition rate and multipurpose utilization is 92%. All index of Meziwo reach the same level or higher than same industry. Meziwo low grade tungsten ore recovering not only protect mineral resources but also improve the economic benefit.

At present, coated cemented carbide has some tendency in diverse composition, multi-layer structure, diverse combination of process and gradient structure of matrix, etc.

1. Diverse coating composition:

Due to big differences of crystal lattice, the hardness, modulus of elasticity and coefficient of thermal expansion between the single layer coated matrix and coating material, the adhesion becomes weaker. If add some new elements in single coating layer, the comprehensive properties of tungsten carbide will be remarkably improved, such as silicon (Si) is beneficial for the hardness promoting and chemical diffusion resistance, the rare earth element Y can improve the resistance to oxidation and the adding Zr, V, Hf will improve the wear resistance.

2. Multi-layer coating structure:

Multi-layer coating structure is one of the main trends of coated cemented carbide, which uses different combination of layers to adapt to different situation. And the layer becomes thinner and tends to nano scale.

3. Diverse combination of process:

Diverse combination of process is suitable for the complicate working conditions in modern industry, such as combined CVD with PVD, which makes CVD-TiCN coating with high wear resistance, and substrate and bonding strength between the coating greatly improved, and PVD-TiN coating having a compressive residual stress effect, two who make carbide cutting tools combined with a better comprehensive performance.

4. Gradient structure of matrix

Gradient matrix structure refers to the cemented carbide substrate gradient process, thereby effectively prevents the cracks internal alloy from expanding.

In order to solve the contradiction between the hardness and the toughness of tungsten carbide, related researchers proposed some optimized measures. The most value in the research has two directions, one is nano cemented carbide, and another is coated cemented carbide. Coated cemented carbide is kind of process that based on traditional tungsten carbide and coated on the surface by titanium carbide (TiC), titanium nitride (TiN), titanium carbide nitride (TiCN), cubic boron nitride (CBN), and aluminum oxide (AL₂O₃).

It not only decreases the abrasion of traditional tungsten carbide cutting tools, but also acted as a thermal barrier and chemical barrier by coated a layer with high hardness and good wear resistance, which coordinates the contradictions between the hardness and the toughness of traditional tungsten carbide cutting tools, improves the precision and the efficiency and extends the service life effectively. So far, coated cemented carbide has more than 40 years of development history, and tends to composite coating instead of single coating. The common coating methods include chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma chemical vapor deposition (PCVD), sol-gel and vacuum cathode arc deposition (VCAD) and so on.