The Gaocheng processing plant, designed for 528,000 tpa and operating since 2014, uses a flexible crushing and grinding circuit with lead, zinc, and sulphur flotation, plus integrated XRT ore sorting and dry tailings handling.
Report context
The Gaocheng Silver-Lead-Zinc Project is located in Yun'an District, Guangdong Province, China. The preliminary design for the mining and processing operation was completed by GDMAI in April 2011, and the processing plant was commissioned in 2014. The effective date of the technical report is 30 June 2024, with the report dated 20 July 2024.
Processing route
Crushing and screening
The plant uses a two-stage closed-circuit crushing process. Run-of-mine ore with a feed size of no more than 350 mm is drawn from a ROM bin by a vibrating feeder into a primary jaw crusher (PE600×900, 75 kW). The crusher product is screened on a double-deck heavy-duty circular vibrating screen (2YKR2460H, 45 kW). Fines of -15 mm are conveyed to a fine ore bin; +60 mm material feeds the secondary cone crusher (PYH-3Z, 220 kW) via a buffer storage bin; and 15–60 mm material is sent to the XRT intelligent sorting system.
Intelligent ore sorting
An X-ray intelligent sorting line (XRT intelligent sorting) was built and put into trial production in March 2023 to replace a previous hand-sorting operation. The 15–60 mm intermediate products enter two-stage vibrating screens (ZK2142) for washing; the pulp from washing is pumped to the grinding system. The oversize clean ore is distributed to the XRT sorting machine, which discards waste rock to a waste rock silo for sale, while the concentrate returns to the secondary cone crusher buffer bin. As of the report date, the pre-sorting feed size class remains under optimisation.
Grinding and classification
Grinding uses a two-stage closed circuit in two parallel series of 800 tpd each. The first stage is a grate ball mill (MQG2700×3000, 400 kW) with a spiral classifier, and the second stage is an overflow ball mill with a hydrocyclone group. Final overflow fineness is 80% passing 75 µm at a solids concentration of 35% to 38%.
Flotation
The flotation circuit is also configured in two parallel series. Lead flotation is one roughing, two scavengings, and three cleanings to produce lead concentrate. Lead tailings flow to zinc-sulphur mixed flotation (one roughing, two scavengings, one cleaning) producing tailings and a zinc-sulphur mix concentrate. This mix then undergoes zinc-sulphur separation (one roughing, two scavengings, three cleanings) to yield separate zinc and sulphur concentrates.
Concentrate dewatering
Lead, zinc, and sulphur concentrates each use a two-stage dewatering process: thickening to 40%–50% solids, then ceramic filtration to a final moisture content of 10%–12%. Dewatered concentrate is bagged and truck-loaded for smelter delivery.
Tailings handling
Tailings are pumped to a deep cone thickener for concentration, with underflow concentration exceeding 72%. The underflow is directed either to a press filtration system or a backfill system. Dry tailings are conveyed to a tailings storage facility and spread by bulldozer on a bench-by-bench basis.
Tin recovery
One production line recovers tin from flotation tailings by gravity separation.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Designed processing capacity | 528,000 tpa (1,600 tpd) | Design |
| Actual annual ore processing volume | 260–630 kt | Historical operating data |
| Grinding circuit capacity per line | 800 tpd (two parallel lines) | Design |
| Final overflow fineness | 80% passing 75 µm | Design |
| Grinding overflow concentration | 35%–38% solids | Design |
| Thickener underflow concentration (tailings) | >72% | Design/operating |
| Final concentrate moisture | 10%–12% | Design |
| ROM feed size | ≤350 mm | Design |
| Crushing product size | -15 mm | Design |
| Crushing circuit | Two-stage closed circuit | Design |
| XRT sorting commissioning | March 2023 | Trial production |
| Primary jaw crusher | PE600×900, 75 kW, 1 unit | Equipment table |
| Secondary cone crusher | PYH-3Z, 220 kW, 1 unit | Equipment table |
| Main screens | 2YKR2460H, 45 kW (1); ZKB2240 washing, 15 kW×2 (2) | Equipment table |
| XRT sorting machine | KK104-24-M, 22 kW, 1 unit | Equipment table |
| Grate ball mill | MQG2700×3000, 400 kW, 2 units | Equipment table |
| Fine ore bins | 718 m³ each, 2 units | Equipment table |
Technical qualifications
The report notes that the XRT intelligent sorting system, built in March 2023, is still in the process of adjustment and optimisation. The feed size class of the pre-sorting system is also under optimisation. The processing plant is designed for flexible operation: one or two grinding and flotation lines may run depending on mining supply quantity, with actual annual ore throughput ranging from 260 kt to 630 kt. No performance or economic data are provided in this recovery method section.
*Source: Technical Report on Gaocheng Silver-Lead-Zinc Project in Guangdong Province, China, effective 30 June 2024, Section 17 Recovery Method.*
