3 Key Factors Affect The Classification of Metal Deposits

In mining engineering, classifying metal ore deposits is the first critical step in selecting mining methods and designing extraction plans. Without proper classification, efficient extraction becomes impossible. What determines the best mining approach for an ore body? It all comes down to three key factors: shape, dip angle, and thickness.

Metal ore deposits are primarily classified based on three characteristics: ore body shape, dip angle, and thickness. The shape dictates the layout of development systems. The dip angle influences ore transportation methods. The thickness determines stope structure parameters. These classification criteria form the foundation for mining method selection, directly impacting both production efficiency and economic returns.

Understanding these classification methods is crucial, but each requires deeper examination. Let’s explore how each parameter affects mining operations. This knowledge separates successful operations from inefficient ones.

 

Factor 1: Ore Body Shape

According to the shape of the ore body, metal deposits are mainly divided into three types: Bedded deposits, vein deposits, and massive deposits. Each type has its unique formation mechanism and characteristics.

 

Bedded deposits 

Bedded deposits are mostly formed by sedimentation or metamorphic sedimentation. They are gradually accumulated in a specific geological environment after a long geological history. This type of deposit is usually large in scale, and its occurrence conditions, such as inclination and thickness, are relatively stable. The composition of useful mineral components is also relatively stable, and the content is evenly distributed. This makes Bedded deposits have certain advantages in the processo de mineração and is convenient for large-scale mining operations. Among ferrous metal deposits, Bedded deposits are more common. For example, some large iron ore deposits have a layered distribution of ore bodies, with small changes in thickness and inclination, which is conducive to the use of efficient mining methods for mining, thereby improving the output and quality of iron ore.

 

Vein deposits

Vein deposits are mainly generated by hydrothermal and vaporization, and minerals are filled in the cracks of the earth’s crust. When hydrothermal fluids deep in the earth’s crust carry a large amount of minerals and rise along the cracks in the earth’s crust, as the temperature and pressure change, the minerals gradually precipitate and fill in the cracks, eventually forming vein deposits. Alteration often occurs at the contact between the vein and the surrounding rock. This is because the minerals in the hydrothermal fluid react chemically with the surrounding rock, causing the mineral composition and structure of the surrounding rock to change. The occurrence conditions of vein deposits are unstable, and the content of useful components is uneven, which brings certain challenges to mining. Non-ferrous metal, rare metal, and precious metal deposits are mostly vein deposits. For example, minas de ouro have complex vein morphology. Precise exploration and mining technology is required during the mining process to ensure the effective recovery of gold resources.

 

Massive deposits

Massive deposits are mainly formed by filling, contact replacement, separation, and gasification. Under these effects, minerals gather in a specific geological environment to form ore bodies of different sizes and irregular shapes, such as lenses, nests, and strains. The boundary between the ore body and the surrounding rock is not obvious, which makes it critical to accurately define the scope of the ore body during mining. Nonferrous metal deposits such as cobre, chumboe zinco often have the characteristics of massive deposits. When mining massive deposits, it is necessary to strengthen prospecting work and use advanced exploration technologies, such as geological radar and geophysical exploration, to accurately determine the boundaries and shapes of the ore bodies in order to fully recover mineral resources and improve resource utilization.

 

Here’s the structured comparison of mining methods based on deposit morphology

Deposit Type	Development Approach	Extraction Method
Bedded deposits	Drift development along strike	Longwall mining / Room-and-pillar
Vein-type deposits	Drifting along the vein structure	Cut-and-fill / Shrinkage stoping
Massive deposits	Shaft sinking with level development	Open stoping / Sublevel caving

 

Key operational characteristics

1. Bedded deposits (e.g., coal seams)

• Flat-lying layers enable continuous mining
• Systematic pillar layout for roof support

2. Vein-type deposits (e.g., gold-quartz veins)

• Narrow, steeply dipping structures require selective mining
• Sequential excavation following vein geometry

3. Massive deposits(e.g., porphyry copper)

• Bulk mining methods for large ore volumes
• Requires substantial ground support for unstable walls

 

Factor 2: Ore Body Dip Angle

According to the different inclination angles of the ore bodies, metal deposits can be divided into four categories: horizontal and slightly inclined deposits, gently inclined deposits, inclined deposits, and steeply inclined deposits. This classification method is closely related to the transportation method of ore and the choice of development methods.

 

Gently inclined deposits (5°- 30°)

The inclination angle of the ore body of gently inclined deposits ranges from 5° to 30°. In the mining of this type of deposit, the ore can be transported by manpower or with the help of mechanical equipment such as electric rakes and conveyors. Human transportation is still used in some small-scale gently inclined deposits with relatively simple mining conditions. Workers carry ore out of the mine by shouldering, carts, etc. The application of mechanical equipment such as electric rakes and conveyors has greatly improved transportation efficiency and is suitable for the mining of large-scale gently inclined deposits. The electric rake uses a winch to pull the rake bucket to rake the ore in the mine and transport it to the designated location; the conveyor can continuously transport the ore to achieve efficient ore transportation.

 

Horizontal and slightly inclined deposits (less than 5°)

The ore body of horizontal and slightly inclined deposits has an inclination angle of less than 5°. The ore body of such deposits is nearly horizontal or has only a slight inclination. During the mining process, various rail or trackless transport equipment can directly enter the mining area. Rail transport equipment, such as mine cars transport ore through tracks laid in the mining area, and has the characteristics of large transport capacity and good stability; trackless transport equipment, such as shovel loaders have strong maneuverability and can flexibly shuttle to every corner of the mining area. They can quickly load and transport ore out of the mining area, greatly improving mining efficiency and reducing labor intensity.

 

Inclined deposits (30° – 55°)

The ore body of inclined deposits has an inclination angle between 30° and 55°. For such deposits, the ore can be transported by its weight using methods such as chutes, slides, or explosive throwing. Chutes and slides are usually made of steel plates or other wear-resistant materials and are placed in the mining area at an angle. The ore slides down the chute or slide under the action of gravity to achieve transportation. Explosive throwing is to use of the explosive energy of the explosives to give the ore a certain initial velocity when blasting the ore, and then throw it to a designated location, and then continue to slide down with the help of the ore’s weight and inertia to complete the transportation process. This transportation method makes full use of the ore’s own weight, reduces the use of mechanical equipment, and reduces mining costs.

 

Steeply inclined ore deposits (greater than 55°)

The ore body of a steeply inclined ore deposit has an inclination angle greater than 55°, and the ore body is relatively steep. In the mining of this type of ore deposit, the gravity transportation method of the ore’s weight is mainly used. After the ore collapses in the mining area, it relies on its gravity to slide down rapidly along the inclined surface of the mining area, and directly falls into the lower transportation tunnel or chute, realizing efficient transportation. With the continuous promotion and application of trackless equipment and other mechanical equipment, the boundaries of classification by ore body inclination will also change accordingly. Some gravity transportation methods that were originally suitable for steeply inclined deposits may also be suitable for deposits with slightly smaller inclinations if equipped with advanced mechanical equipment; conversely, some transportation equipment that was originally used for gently inclined deposits may also play a role in steeply inclined deposits after improvement, making the mining of deposits more flexible and efficient.

 

 

Factor 3: Ore Body Thickness

In mining operations, accurately defining the ore body thickness is a key factor that influences the entire extraction process. Ore body thickness not only affects the choice of mining methods but also directly impacts extraction efficiency and resource recovery rates. During the mining development process, we typically categorize ore body thickness into vertical thickness (true thickness) and horizontal thickness. Choosing the appropriate thickness standard is crucial for different types of ore deposits. For instance, horizontal thickness is often adopted when mining steeply dipping ore bodies, whereas vertical thickness is more commonly used for inclined, gently dipping, or horizontal deposits.

To delve deeper into this topic, we can refer to the article “What Are the Best Mining Strategies for Different Ore Body Thicknesses?“ This article provides a detailed analysis of the optimal mining strategies corresponding to different ore body thicknesses, utilizing empirical data and case studies to discuss how to optimize mining methods under various thickness conditions to enhance resource recovery rates and reduce extraction costs.

 

Conclusão

Classifying metal ore deposits by shape, dip angle, and thickness forms the foundation of efficient mining operations. These parameters determine development strategies, equipment selection, and extraction methods. Tabular shapes require different approaches than massive deposits. Steep dips enable gravity-assisted methods unavailable in flat-lying ores. Thickness dictates whether selective or bulk mining proves appropriate. Mastering these classifications ensures optimal resource recovery while controlling costs and maintaining safety. Every successful mining operation begins with thorough deposit characterization.