Solution of primary crushing at limestone processing plant

This paper gives a presentation of primary crushing at stone aggregates production plant from deposit. The paper has been developed from The Main Mining Project of the new processing plant for limestone and production of stone aggregates from deposit. First problem to be solved at primary crushing was the removal of waste rock being occurred in the useful component by mining.

Increased needs for stone and stone aggregates used in construction industry, In order to meet those demands, the already existing plant has been reconstructed, while completely new equipment has been purchased for the new production plant for crushing and sizing of limestone. Project planning of the new processing plant and elaboration of the Main Mining Project with the previous capacity of 250 t/h. Thus total capacity of the processing plant with the reconstructed part amounts about 500 t/h. Limestone processing involves primary crushing and removal of waste rock, secondary and tertiary crushing and sizing of the finished products. Processing equipment has been connected by the system of conveyor belts, thus enabling transfer of products through process phases as well as transfer of finished products to the appropriate dumps.

According to working regime, scheme projected this way enables production of aggregates of the following class sizes: -63+32 mm; -32+16 mm; -16+8 mm; -8+4 mm and -4+0 mm. Related to market placement of finished products, the scheme includes possibility for coarser classes to be transported back at the primary crushing which increases the share of class -4+0 mm up to 100 % related to entry mass of secondary crushing.

According to project task and Investitor’s requests, Limestone and Stone Aggregates Production Plant is being projected for the following conditions:

• Capacity of raw limestone 295 t/h
• Waste quantity 45 t/h
• Capacity of primary crushed limestone class –200+32 mm 250 t/h
• Capacity of crushed limestone 4.130 t/day
• Waste quantity (–30+0 mm) 630 t/day
• Capacity of class (–200+30 mm) 3.500 t/day

Primary crushing plant – data

For primary crushing of limestone at the open pit:

• Jaw crusher type pew 1100, aperture 110×120 cm, exit aperture 15 x27 cm
• Vibrating feeder with screen type GF9042, aperture for waste separation 30 mm
• Conveyor belt for crushed material (–200+30 mm)
• Conveyor belt for waste transportation (–30+0 mm)
• Plant capacity 350 t/h for bulk materials and 250 t/h for rocky materials
• Plant dimensions
• Total length B = 15.100 mm
• Distance between carrying plates A = 6.800 mm
• Total height C = 6.450 mm
• Width D = 4.900 mm
• Entry cage volume V = 21 m3
• Plant mass (with entry cage) Q = 56 t
• Electro-motor force P = 132 kW