Mining technology: open-pit mining, underground mining, and marine mining!

As the cornerstone of global economic development, the mining industry provides indispensable basic raw materials for various industries. From steel and cement required in the construction field, to key metals such as copper and lithium relied on by the electronics industry, to coal and oil in the energy industry, the products of the mining industry are widely used in all aspects of social economy.

In 2023, the global mining and metals market size reached 1.5 trillion US dollars, and it is expected to grow to 2.36 trillion US dollars by 2031, with a compound annual growth rate (CAGR) of 5.20%. Its development trend not only profoundly affects the industrial process of various countries, but is also closely related to the prosperity and stability of the global economy.

In modern mining operations, efficiency, safety, and sustainability have become the three core goals. Improving efficiency aims to obtain more high-quality mineral resources at a lower cost and in a shorter time to meet the growing market demand; ensuring safety is related to the life and health of practitioners and the stable operation of enterprises, and is the basic premise of mining operations; while sustainability focuses on the long-term rational use of resources and the protection of the ecological environment to achieve the long-term development of the industry. To achieve these goals, mining technology is constantly innovating, gradually moving from traditional methods to highly automated, intelligent and green.

01Conventional mining methods

1. Open-pit mining

Open-pit mining is a method of mining ore directly from the surface by removing the covering above the ore body. It is suitable for ore deposits with shallow burial and wide distribution. Its operation process covers key links such as drilling, blasting, mining, transportation and soil discharge.

Drilling: Use drilling equipment to drill blastholes on the ore bed to prepare for subsequent blasting operations. Parameters such as the depth, diameter and hole spacing of the drilling need to be reasonably designed according to factors such as the nature of the ore and blasting requirements.

Blasting: Load explosives into the blastholes and detonate them through the detonator to break the ore. It is crucial to optimize the blasting parameters, including the type of explosives, charge, detonation method and sequence, to ensure that the ore achieves the ideal crushing effect while reducing the impact on the surrounding environment.

Mining and loading: Use mining and loading equipment to load the blasted ore into the transportation equipment. Operators need to reasonably select the mining and loading method and equipment action according to the distribution and blockiness of the ore to improve the mining and loading efficiency.

Transportation: The transportation equipment transports the mined ore to the beneficiation plant or the designated storage location. During the transportation process, it is necessary to reasonably plan the transportation route to ensure the normal operation of the transportation equipment, improve transportation efficiency and reduce transportation costs.

Soil dumping: The waste rock generated during open-pit mining is dumped into the designated soil dump. The site selection and construction of the soil dump need to consider factors such as terrain, geological conditions, and environmental protection. At the same time, effective soil dumping technology and management measures should be taken to prevent landslides, mudslides and other disasters from occurring in the soil dump, and reduce pollution to the surrounding environment.

Open-pit mining is widely used in the mining of porphyry copper, coal and other minerals. Take the Escondida porphyry copper mine in Chile as an example. As one of the largest open-pit copper mines in the world, it produces millions of tons of copper concentrate each year through large-scale open-pit mining, meeting the large demand of the global copper market.

2. Underground mining

Underground mining is suitable for deposits where the ore body is buried deep and is not suitable for open-pit mining economically and technically. There are various methods, including room-and-pillar method, longwall mining method, caving method, etc. Each method has its own characteristics and applicable scenarios.

Room-and-pillar method: alternately arrange the mine room and the pillar in the ore block, first recover the mine room, and then decide whether to recover the pillar according to the situation. When recovering the mine room, shallow holes or medium-deep holes are usually used to fall the ore to the bottom of the mine room, and then the ore is discharged by electric rakes, scrapers and other equipment. The room-and-pillar method has the advantages of small mining workload, simple production process, and good ventilation conditions. It is suitable for mining deposits with stable ore and surrounding rock and moderate ore body thickness.

Longwall mining method: widely used in efficient mining of coal mines. The operation is in the longwall working face, the coal mining machine continuously mines coal along the coal seam, and the mined coal is transported out by the scraper conveyor. The hydraulic support timely supports the roof behind the coal mining machine, and moves forward in sequence as the coal mining machine advances. This method has the advantages of high production efficiency, high resource recovery rate, and safe operation.

Collapse method: mainly used for mining low-grade and unstable surrounding rock deposits. This method controls ground pressure by forcibly or naturally collapsing the surrounding rock to fill the goaf. During the mining process, first, the bottom of the ore body is pulled to form a compensation space, and then the ore is collapsed by deep hole blasting and other methods. The collapsed ore slides to the mine exit tunnel under the action of gravity and is transported out by equipment such as shovel loaders. The collapse method has the advantages of low mining cost and large production capacity, but it also has the problem of high ore depletion rate.

3、Marine Mining

Marine mining refers to the activities of mining polymetallic nodules, cobalt-rich crusts, seafloor hydrothermal deposits and other mineral resources at the bottom of the ocean. Polymetallic nodules are widely distributed on the deep seabed and are rich in manganese, nickel, copper, cobalt and other metal elements, with great economic value. However, its mining technology faces many difficulties, such as the complex environment of high pressure, low temperature and darkness in the deep sea, as well as the potential impact of the mining process on the marine ecological environment. At present, the mining of polymetallic nodules mainly adopts hydraulic lifting, air lifting and continuous chain bucket technologies.

Hydraulic lifting system: lifts the mixture of seafloor nodules and seawater to the mining ship through a high-pressure water pump;

Air lifting system: uses compressed air to form an updraft in the pipeline to drive the nodules up;

Continuous chain bucket system: collects nodules on the seabed through a chain equipped with a bucket and lifts them to the ship.

Robots and remote control systems play an indispensable role in marine mining. Due to the harsh deep-sea environment and the difficulty of direct manual operation, underwater robots can carry various detection and collection equipment to conduct seabed mineral exploration and mining operations under remote control. These robots have high-precision positioning, flexible operation capabilities and powerful data transmission functions, and can accurately identify and collect mineral resources in complex seabed terrain.

However, marine mining has also caused widespread environmental controversy. Suspended particulate matter generated during the mining process may affect the breathing, feeding and reproduction of marine organisms, and destroy the food chain of the marine ecosystem; the destruction of the seabed landforms may cause the loss of habitats of some benthic organisms and affect biodiversity. At present, the international community is actively formulating relevant regulations and standards to regulate marine mining activities, and to protect the marine ecological environment to the maximum extent while developing resources.

Xinhai Mining is a service company for mining engineering general contracting and production operation management. It has the first-level qualification for mining engineering construction general contracting and can undertake various metal and non-metallic mineral mining projects, including mine (underground mining) projects, open-pit mining projects, mineral processing projects, tailings pond projects, underground electromechanical equipment installation and ground production systems and supporting projects in the mining area.

Xinhai Mining Project Case

Sheng'an Mining 4000TPD Molybdenum Mining Project

Zhangjiakou Sheng'an Mining Molybdenum Iron Mine has a vast mining area and excellent ore body conditions. The project is mainly based on underground mining, combined with medium-long hole blasting technology, with a designed processing capacity of 4,000 tons/day and 1.2 million tons/year, mainly mining molybdenum iron ore. Xinhai Mining will be responsible for the whole process of construction from infrastructure projects such as shafts and ramps to subsequent mining. After completion, efficient and safe mining projects will be realized.