Ore Textures and Structures

The grade of ore is used to determine the concentration of the desired ingredient present in an ore. To establish if a rock is of sufficiently high grade to be worth mining and thus termed an ore, the value of the metals or minerals it contains must be evaluated against the cost of extraction.

Oxides, sulphides, silicates, and native metals like copper and gold are the most common minerals of interest. The ore must be treated to extract the elements of interest from the waste rock. Ore bodies are created by several geological processes, collectively known as ore genesis. The meaning of ore is the breakage of rocks or degraded rocks.

The Mineral Deposit’s Geology

The mining area is located in the heart of the Kangzhen anticline Luziyuan subsidiary anticline axis, in the southern Baoshan-Zhenkang block. It develops NE and NW trending faults. The upper Cambrian and Ordovician marble-quartz schist and grey-green argillite marble-marbleisation-limestone, which touch with faults, make up the major strata of this mine.

The F1, F2, and F3 faults, as well as the overall output vein type, stratiform or steroid, strike from NE to NW and dip steeper. They all exert strict control over the ore bodies. The ore body has a clear upper element trend, with the upper half being a lead-zinc mine and the lower part being a skarn type magnetite.

Types of Ores and Their Properties

• Sphalerite 

Sphalerite was formed in two stages, diagenetic metamorphism and hydrothermal reform, with brown-yellow and brown-red internal reflection. The output form was hypidiomorphic and xenomorphic granular aggregate structure. Particle sizes ranged from 0.005 to 3mm, mostly around 0.5mm, filled or disseminated among the particles of gangue minerals. 

The aggregate has net veins, thin veins, and crumb veins and is frequently found with galena, chalcopyrite, and magnetite. 

• Galena

As the main metal mineral, galena was formed in the same period as sphalerite in the ore. A small number was created in the sedimentary diagenetic period, whereas a large number formed in the hydrothermal reformation metallogenic period. Grey hypidiomorphic granular particle sizes ranged from 0.005 to 1.2 mm. 

Galena is found predominantly along with the sphalerite wall. It is disseminated around sphalerite particles on the reaction side and in metasomatic dissolution textures. Galena is a narrow vein with sphalerite replacement that originated slightly later than sphalerite.

• Magnetite 

Magnetite is a mineral that forms mainly in the late heated fluid transformation function. It is found in skarn type iron ore. A tiny amount is found in principally skarn type chlorite and quartz schist type lead ore bodies and the same type of rock. Its granular form is a black xenomorphic particle with a size range of 0.05 to 0.5 mm in diameter. 

Dissemination happens when magnetite crushes and forms many fissures that are wrapped and disseminated in colloidal pyrite and pyrrhotite.

Structure of Ores

Some ore structures include diffuse structure, vein-like structure, droplets of emulsion-like structure, etc. The main ore textures entail crystalline granular texture and replacement texture. 

The fabric of the ore is determined by the ore’s properties. The mining area may be classified into two categories based on the spatial analysis of relationship characteristics. Based on this division, there are three periods: 

• Sedimentary diagenesis
• Initial source formation
• Hydrothermal diagenesis

Stages of reformation include metallogenic and supergene stages. Luziyuan Pb-Zn was thought to be the source. Early hydrothermal deposits are polymetallic deposits, whereas late hydrothermal deposits are late hydrothermal deposits.

Texture of Ores

Ore structures include banded, dispersed, and vein structures, among others. Apart from these independent structure types, it frequently generates compound structures with many configurations, such as: 

• Disseminated-banded structure
• Disseminated-net vein structure 
• Disseminated-vein structure 
• Disseminated-banded-net vein-fine vein structure

As mineralisation has increased, metal minerals have a dispersed structure that has evolved into: 

• A dense disseminated structure
• A banded structure
• A combination of two or more complex geological patterns

Brecciated, interstitial, crushing, and corrugation structures are common in fault fracture zones. Furthermore, secondary oxidised minerals were found along the protolith of the weathering lattice generated by precipitation crystallisation radial structure. These minerals include:

• Smithsonite
• Limonite
• Other colloidal minerals

Above all, the Luziyuan lead-zinc ore bed has both sedimentary deposit ore fabric and late hydrothermal ore deposit features. In fact, the various types of fabric are not entirely independent and mainly occur in their compound fabric. 

In particular, the relationship between the formation of the fabric of sedimentary diagenesis and thermal metamorphism is very close.

Conclusion

The shape and texture of an ore deposit can affect the extraction of its metal. The mining area is classified based on ore fabric characteristics, metal minerals and gangue mineral combination, type and shape, and mineral in space analysis of characteristics of the relationship. The first period is sedimentary diagenesis, followed by the initial source of formation. The last period is hydrothermal reformation.