Basic knowledge of open pit mining

I. Introduction to limestone:

Limestone (Limestone), referred to as limestone, is a carbonate rock with calcite as the main component, sometimes containing dolomite, clay minerals and detrital minerals, belongs to, is a kind of diagenesis. Limestone is mainly formed in the shallow sea environment, belongs to the formation of biological sedimentation, its main formation is the settlement and accumulation of Marine organisms, coupled with animal and plant detritus from the land and sediment together in the riverbed or seabed after the formation of geological changes.

Second, the composition of limestone structure:

The composition of limestone is mainly calcite, accompanied by dolomite, magnesite and other carbonate minerals, but also mixed with other minerals, such as magnesite, quartz, stone pulp, opal, aluminum silicate, pyrite, pyrite, goethite, glauconite and so on. In addition, in individual types of limestone, there are coal, asphalt and other organic matter and gypsum, anhydrite and other sulfates, as well as phosphorus and calcium compounds, alkali metal compounds and strontium, barium, manganese, titanium, fluorine and other compounds, but the content is very low. The main chemical composition of limestone is CaCO3, which is easy to dissolve, so stone forests and karst caves are formed in limestone areas, which is called karst topography.

The structure of limestone is relatively complex, there are two kinds of clastic structure and grain structure, in which the clastic structure is mostly composed of particles, micrite matrix and sparry cement, and the grain structure is the crystal particles precipitated by chemical and biochemical processes.

Iii. Classification of limestone:

According to its deposition area, limestone is divided into Marine sedimentary rocks and continental sedimentary rocks, with Marine sedimentary rocks being the most.

According to its formation type, limestone can be divided into three types: biological sedimentary, chemical sedimentary and secondary.

According to the different components contained in the ore, limestone can be divided into three kinds of siliceous limestone, clayey limestone and dolomitic limestone.

According to the structure, limestone can be divided into bamboo foliate limestone, shape limestone, mass limestone and so on

Four, the characteristics of limestone:

1. Limestone is widely distributed, the lithology is uniform, easy to mining and processing, is a very widely used building stone.

2. Limestone has good processability, gas permeability, sound insulation and good cementation properties, can be deeply processed applications, is an excellent building decoration material.

3. Limestone is widely produced, the color texture is quite abundant, there are gray, gray, gray black, yellow, light red, brown red and other colors, there are good decorative.

4. The texture of limestone is fine, the processing adaptability is high, the hardness is not high, and the carving performance is good. It is easy to make small shelf carving, which is suitable for beginners to choose, but because the limestone is easy to dissolve, it is not suitable for outdoor carving.

5. Limestone is widely used in metallurgy, building materials, chemical industry, light industry, construction, agriculture and other special industrial sectors are important industrial raw materials.

Basic concept and description of open pit mining

Open-pit mining is the mining of ore in an open space within a certain range, stripping away the topsoil covering the upper part of the ore body and the surrounding part of the rock. So in order to extract the ore, the ore must also be mined.

I. Basic statement:

1. Step (bank) : (Figure 1-1) When mining, the ore and rock are divided into horizontal layers with a certain thickness from top to bottom, and the mining is carried out by independent mining and transportation equipment. Each layer maintains a certain advance relationship, thus forming a ladder shape.

The steps are composed of the following elements: upper flat plate, lower flat plate, slope surface, slope top line, slope bottom line, height, slope Angle.

Steps:

Work step - work flat layout of mining and transportation equipment.

Non-working step - security platform: used to cushion and intercept sliding rocks and slow down slope angles.

Sweeping platform - Stop sliding rocks and clean them with sweeping equipment.

Transport platform - as a link between the work step and the access ditch transport.

(2) Working line (Avdvance line) : a section of mineral rock that has been prepared to form.

3. excavation zone: During mining, the steps are divided into several strips, which are mined successively, and each strip is called excavation zone.

2. Electric shovel... Depends on shovel digging and unloading radius.

4, Each strip mining can also be divided into several sections with independent mining equipment.

Parameter: Length... The length of a working line occupied by an electric shovel.

5. Open pit:

Divided by use:

① Access ditch... Establish transportation channels between mining levels. (AB in BL-4).

② Open a ditch... Establish the first work line (initial step) as shown in CD in Figure L-4.