Cradle to Gate
Identity ID
9977015b-5690-41ae-9421-2b1f0b8edb2d
Materials
Associated ID
ba3be30c-5c86-4f68-a389-09b5b8ffe5a1
Included activities starts
Included activities ends
Description
This dataset represents a life cycle inventory (cradle-to-gate) of lignite production, starting from geological exploration in underground mining, covering all activities related to raw coal production, but excluding coal washing and preparation processes, as well as direct and indirect greenhouse gas emissions from the production of equipment such as conveyors and mining vehicles, personnel transportation during coal production, and daily office operations. The dataset was compiled from multiple data sources in accordance with national standards such as "Cleaner Production Standard for Coal Mining and Dressing Industry" (HJ 446-2008), "Pollutant Discharge Standard for Coal Industry", and "Soil Environmental Quality Standard of the People's Republic of China", and is representative of the average production level in Guangxi.
Activity Description
This dataset describes underground coal mining, with the following process steps:
1. Drivage of roadways
The first step in underground mining is the drivage of roadways, which involves creating access tunnels to the coal seams. These roadways are typically excavated using roadheaders or by blasting. Roadways are categorized into main tunnels (such as haulage and ventilation roadways) and auxiliary tunnels (such as pedestrian passages and drainage tunnels), serving functions including coal transportation, ventilation, personnel access, and movement of equipment and waste materials. Coal Mining
After the completion of tunnel excavation, coal extraction is the core step in underground mining. Depending on the structure, thickness of the coal seam, and mining technology, different coal mining methods are adopted. Common underground mining methods include:
Longwall Mining: A large-scale mining method where the coal seam is extracted over a wide area at once, usually accompanied by tunnel support.
Room and Pillar Mining: The coal seam is divided into small blocks, supported by pillars, and extracted progressively. Machinery and Equipment
Coal mining and transportation processes heavily rely on machinery and equipment, including:
Shearer: Used for cutting coal seams in longwall mining.
Hydraulic Supports: Support the roof to prevent tunnel collapse.
Continuous Miner: Used for tunnel excavation.
Belt Conveyor: Transports extracted coal from the working face to the transportation system. Underground + In-plant Transportation
Underground transportation refers to moving coal from the working face to the shaft portal, typically using belt conveyors or mine carts. After reaching the portal, coal is transported to the coal preparation plant or external markets via in-plant transportation systems (such as belt conveyors or trains). Improving efficiency in this phase directly affects the efficiency of the entire production process.
5. Ventilation
Ventilation systems are an essential component of underground mining. Due to the confined nature of underground operations, ventilation systems must ensure a continuous supply of fresh air, remove hazardous gases (such as methane) and dust, and safeguard worker health and safety. A typical ventilation system consists of fans, ducts, and air outlets, which collectively maintain airflow underground.
6. Pollutant Treatment and Disposal
Main pollutants generated during underground mining include:
Mine Water: Typically containing coal dust, suspended solids, and chemical substances, it requires treatment through sedimentation tanks and water treatment facilities.
Coal Dust: Harmful to miners' health and the environment, it is usually controlled by wet dust removal, spray suppression, and other methods.
Waste Residue: Mine waste and gangue are transported to the surface, stored in designated areas, and managed with land reclamation. Ecological Restoration and Management
The impact of underground mining on the surface environment is mainly reflected in ground subsidence, changes in groundwater flow direction, etc. Therefore, ecological restoration measures include:
Land Reclamation: Filling subsidence areas caused by mining to restore agricultural use or vegetation coverage.
Water Resource Management: Restoring groundwater systems and preventing water pollution or loss.
Vegetation Restoration: Planting vegetation in affected areas to prevent soil erosion and improve the ecological environment.
Process Description
Guangxi lignite is mainly distributed in the Nanning coalfield and Baise coalfield, with coal quality characterized by ash content of 27.38–35.28%, volatile matter of 48.82–50.57%, total sulfur of 1.31–1.93%, and net calorific value on an as-received basis (Qnet,ar) of 4500 kcal/kg.
Time period
2022
2026
Geography
China,Guangxi Zhuang Autonomous Region
Geography comment
Forming Guangxi's average data through merging data from multiple sources.
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
Underground mining includes tunneling, coal extraction, machinery and equipment, underground and in-plant transportation, ventilation, pollution treatment and disposal, ecological restoration and management.