The Ultimate Guide to Nickel Mining Process

Nickel is the fifth most common element on earth and can be used to produce other alloys with special properties. Corrosion-resistant alloys can be used in chemical plants, and "super alloys" can withstand extreme temperature conditions, so they can be used in aviation. Nickel is also used in the electronics industry as a substrate for chrome plating.

At current mining rates, the known reserves of nickel ore can last another 100 years. Nickel element is contained in underground nickel sulfide ore, which is mined by underground mining method. It also exists in laterite nickel ore, which is mined using the open-pit mining method.

Nickel open pit mining usually covers the whole boundaries. Horizontal slices with certain thickness are defined to extract nickel ore from top to bottom until reaching the ultimate or temporary boundary and forming the ultimate or temporary slope.

Technology Characteristic

The stripping method usually includes the positioning of open trench, advancing direction, and the arrangement and factors of working face. It impacts both the production technologies and economic benefits in the initial stage. Applying appropriate stripping methods to nickel orebodies with different technical conditions can reduce the amount of capital construction, accelerate the project schedule and gain better initial economic results.

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1. Determine the slice height (bench height) according to the equipment capability. The bench height is usually between 6m and 15m: the bigger the mine, the larger the value. And the bench height for medium-to-large mines is usually 10m or 12m.

2. Determine the ultimate slope angle and integrant parts of ultimate pit slope according to the rock property, geologic structure, hydrogeology and mining depth around the boundaries. The ultimate slope angle is usually between 30° and 55°: bigger values should be chosen if rock stability is better and mining depth is small, and vice versa.

3. Calculate the economic reasonable stripping ratio according to the techno-economic indicator for open pit mining, and then determine the boundary stripping ratio based on the principles of boundary delineation. The boundary stripping ratio is usually between 4 and 10 (m3/m3): smaller values should be chosen if the mine is small, and vice versa.

4. Determine the road layout and parameters according to development and transport mode.

5. The ultimate pit slope is composed of bench height, bench slope angle, cleaning berm, safety berm and transport berm. The slope angle should be the ultimate slope angle.

Room and Pillar Stoping

Post pillars are reserved in the stope for support. According to the depth of blasting holes, there are two mining methods: short-hole room and pillar stoping; medium- and deep-hole room and pillar stoping. The former adopts short-hole rock drill for nickel ore bodies with a thickness of less than 3-4m, and nickel ore is transported by electric rake or scraper to the stope orepass. The latter adopts medium- and deep-hole rock drill for ore bodies with a thickness of 5-30m, and nickel ore is transported by scraper onto the dump truck.

Technology Characteristic

• It is usually applied in exploiting horizontal or slightly inclined, stable or moderately stable nickel ore bodies with a thickness of less than 30m.

• Low costs, easy mechanization, and simple technology.

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Short-hole Shrinkage Stoping

Air-leg rock drill is adopted to drill horizontal holes. One third of nickel ore is discharged, while the other is left as the temporary working platform for next-stage drilling and blasting. After nickel ore drawing, such ore is discharged in a centralized way. Nickel ore is transported by loader onto the mine car in the ore drawing roadway, and the car is driven by electric locomotive.

Technology Characteristic

• Sharply inclined, basically stable, and ultrathin-to-thin nickel ore bodies;

• Ore without agglomeration and spontaneous combustion.

• Simple structure, small amount of stope preparation, easy technology and low dilution rate.

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Sublevel Room and Pillar Stoping

Vertically, there are 3-4 sublevels in the stope room, with each measuring 12-15m in height. At each sublevel, medium- and deep-hole drill is adopted to construct upward fan-shaped holes, and charging jumbo to put explosives into the holes. Caved nickel ore is discharged by scraper into orepass.

Technology Characteristic

• Stable, sharply inclined orebodies with thickness above the moderate level.

• Stoping at several working faces, centralized management, high stoping capacity, mechanization, high degree of safety, and good ventilation.

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Block Open Stope Succedent Filling

Deep-hole drill jumbo is adopted to construct downward parallel deep holes in the drilling chamber. After side caving, nickel ore is discharged by scraper into orepass. Nickel ore block has two-stage stoping. After the first-stage stoping, mined-out areas are filled with cemented filling materials to form stable support. Then the second-stage stoping is carried out.
Technology Characteristic

• Stable, sharply inclined, thick and extremely thick orebodies; extremely thick inclined, slightly inclined and horizontal orebodies.

• Large production capacity, centralized management, low mining costs, and high degree of safety.

Technical Index

Upward Horizontal Slicing Filling

Vertically, there are 3-5 sublevels in the stope room, with each measuring 12-15m in height. Each sublevel includes 4-5 slices with each measuring 3m in height. Short-hole drill is adopted to drill horizontal parallel holes. Caved nickel ore is discharged by scraper via stope access road into orepass. Slicing filling is carried out from bottom to top. Stoping must be conducted on stable filling bodies.

Technology Characteristic

• Inclined or sharply inclined nickel ore bodies with rock stability above the moderate level and unstable-to-stable surrounding rock.

• Low loss rate and dilution rate, good ventilation, high degree of safety, and application in deposits with various occurrence.

Technical Index

Sublevel Caving without Sill Pillar

Vertically, there are 3-5 sublevels in the stope room, with each measuring 12-15m in height. Medium- and deep-hole drill is adopted to drill upward fan-shaped holes in the drilling roadway. There should be overburden higher than the sublevel above the stoping face. When stoping is carried out in two sublevels, the upper sublevel should be exploited ahead of the lower one. Caved ore is discharged by scraper via sublevel roadway into orepass. After the completion of each sublevel, the orepass mouth should be sealed in time.

Technology Characteristic

• No caving impact on the ground, and nickel ore bodies without large water bodies and quicksand above;

• Medium-level ore with lower grades and permission for certain loss and dilution;

• Sharply inclined orebodies with thickness above the moderate level or slightly inclined, ultra-thick orebodies (nickel ore has no agglomeration and spontaneous combustion);

• Unstable or moderately stable hanging-wall rock, stable footwall surrounding rock, and stable or moderately stable orebodies.

• Simple stope structure, high flexibility, and no need to reserve pillars;

• Simple technology, and comprehensive mechanization through efficient automatic rock drilling, and loading and hauling equipment;

• High degree of safety;

• Large labor productivity and production capacity;

• Higher recovery under large dilution rates.

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The above introduce many methods for nickel mining. Before we have also talked about nickel extraction process. If you want to know more about nickel mining and processing methods, you can contact the online service, our sales will contact you soon.