Automatic transformation to make up for the decline of ore grade

Tara Mine started production in 1977, with an annual output of 2.6 million tons, making it the largest zinc mine in Europe.

Tara is a gently inclined ore body, so its dip angle problem brings great difficulties to mining operation. From the production point of view, a lot of roadway excavation is needed to continue mining ore bodies. Deep hole open stope mining is still very suitable for thick ore bodies, but the difficulty will increase when the ore seam becomes thinner.

There are still many challenges facing Tara mine. The company's mining goal is about 2.6 million tons of ore per year, but whether this goal is achieved depends on the availability of stopes, and it takes 14.3 kilometers to maintain it every year.

The decline of grade is also one of the problems that Tara mine must overcome. When the mine started production in 1977, the grade of zinc was about 12%. In 2019, it was only 6.3%, and it will drop to 5.7% this year, and it is expected to drop to 5.3% in the future. Therefore, according to the metal content, the profit per ton of ore is decreasing, which obviously affects the profitability of the mine.

In order to make up for this to some extent, it is urgent to focus on improving productivity and reducing costs. In terms of production, consider whether the utilization rate of equipment can be improved, thus reducing the capital requirements. For mines, it is also of great significance to increase production at the same cost.

In 2011, Tara Mine began to consider the problem of automation transformation.

In 2015, the mine began to conduct automation tests in the closed dead zone of the mine to confirm the feasibility of the system. After the experiment proves that the system is effective, the next step is to determine the best process of using the system to maximize the return on investment. Tara chose the ore mining operation. In this operation, mines are usually loaded directly from the stope to trucks or ore chutes.

Tara purchased a Taishan Tevik DD422i jumbo and two sandvik battery-driven fully automatic double-arm rock drilling jumbo DD422iE rigs. These three equipments ensure high drilling accuracy and realize high automation at the same time, and maximize the amount of excavation per round. These rigs can drill holes automatically, and workers usually set them to drill holes automatically at lunch time.

In addition to three smart sandvik trolleys, Tara also invested in a series of automatic loading and transportation equipment, including 3 Taishan Tevik LH517 scraper, 2 sandvik LH621 scraper and 1 LH621i scraper, and a sandvik TH663i truck. Previously, the mine had purchased eight underground trucks and rigs from sandvik.