# Energy Optimisation of Industrial Limestone Grinding Using ANN
## 3 Study Object  
Kopalnia Wapienia \"Czatkowice\" sp. z o.o. is an open-pit mining facility that extracts Carboniferous limestone deposits. The mining area is extensive--currently approximately 135 hectares. The extraction of limestone is conducted using open-pit methods with a wall-and-bench system and multi-wing advancement of the working front. The mined limestone is used, among other applications, for the production of high-quality sorbents for flue gas desulfurization in power plants.  
Kopalnia Wapienia Czatkowice carries out a comprehensive process of limestone extraction and processing, which includes several key technological stages:  
* Mining Plant: Extraction and aggregate production;* Mineral Processing Department: Mechanical processing plant, limestone grinding plant, storage and loading unit, and milled product packaging station. The entire production process is divided into individual stages, as illustrated in Figure 1.  
Depending on its chemical composition (e.g., lead, silica, or magnesium content), the raw material is routed either to the aggregate plant or to the processing plant. Limestone with increased silica content is used for the production of commercial aggregates, whereas raw material with lower silica content is processed into limestone flour, sands, and stones.  
* Grinding Plant: The technological grinding system, shown in Figure 2, consists of two parallel twin processing lines featuring high complexity and technological advancement.  
The main grinding equipment is a roller mill manufactured by the German company GEBR: PFEIFER (Kaiserslautern, Germany) (Figure 3), with a throughput of up to 80 tons per hour.  
Material enters the mill through buffer tanks, from which it is transported to the mill by dosing scales. The raw material falls onto a rotating grinding table and is crushed between rollers, resulting in grain sizes down to 4 mm. The grinding process is tightly integrated with drying--performed using a gas burner located at the mill inlet, which heats the air to approximately 250 \({}^{\circ}\)C.  
The ground particles are then carried by an airstream generated by the process fan. A separator with a rotating rotor classifies the particles into fine and coarse fractions. Fine particles are directed to a dedusting installation and transported to storage as limestone  
Figure 1: Production process at KWC divided into production lines.  
Figure 2: Simplified flow diagram of the grinding process at KW Czatkowice.  
flour with a grain size of 0.045-0.080 mm, while coarser particles (>0.08 mm) are sent back for further grinding or stored.  
The cleaned air from the filter is directed to the mill fan, which discharges it through the chimney and returns it to the mill inlet as part of a closed-loop system.  
The production line is fully automated, and the entire technological setup is equipped with measurement and control instrumentation. A simplified diagram of the grinding line with key measurement points is shown in Figure 4.  
Figure 4: Simplified technological diagram of the limestone grinding and classification control system at KW Czatkowicz.  
Figure 3: Structure of the roller mill at KW Czatkowicz.  
The analyzed system records over 3500 variables, enabling extensive process analysis. Process control relies heavily on operator experience, and the system is designed with redundancy (e.g., two clustered application servers, duplicated Ethernet connections, etc.) to ensure production continuity even in the event of component failure.