The Songjiagou Gold Project processes ore from underground and open pit sources through three plants with a combined capacity of 7,400 tpd and a common flotation circuit design.
The Songjiagou Gold Project, operated by Majestic Gold Corp., is an active mining operation located in the Muping District of China. The treatment facility consists of three plants commissioned in stages. Two plants were put into operation in 2006 with processing capacities of 200 tpd and 1,200 tpd, and a third plant was put into operation in May 2011 with a capacity of 6,000 tpd. The total processing capacity is 7,400 tpd. The site layout places the 1,200 tpd plant in the centre of the processing area, with the 200 tpd plant located northwest and the 6,000 tpd plant located east of the central plant.
The 200 tpd plant processes ore mined from the underground operation. This plant is not discussed in detail in the technical report because its operation was contracted out in April 2011. From 2006 to January 2013, a total of 444 kt of underground run of mine inventory, with an average grade of 0.85 g/t Au, was processed by this plant.
The 1,200 tpd and 6,000 tpd plants process ore from the open pit operation and adopt similar flowsheets. The ore is ground and the slurry, with a particle size of 50% greater than 0.074 mm after spiral classification, is subjected to a flotation circuit. This circuit comprises one stage of roughing, one stage of cleaning, and two stages of scavenging. The gold concentrate is dehydrated and then sent for metallurgical processing. From 2008 to 2012, these two plants processed a total of 2.7767 Mt of run of mine material with an average grade of 0.30 g/t Au, producing gold concentrate grading 23.66 g/t Au, with an overall recovery rate of 83.44%.
Critical Data
| Parameter | Value | Unit | Notes |
|---|---|---|---|
| Total processing capacity | 7,400 | tpd | Sum of 200, 1,200, and 6,000 tpd plants |
| 200 tpd plant grind size | 50% >0.074 | mm | After spiral classification |
| Underground ROM processed (2006 to Jan 2013) | 444 | kt | Average grade 0.85 g/t Au |
| Open pit ROM processed (2008 to 2012) | 2.7767 | Mt | Average grade 0.30 g/t Au |
| Gold concentrate grade (open pit plants) | 23.66 | g/t Au | 2008 to 2012 |
| Overall gold recovery (open pit plants) | 83.44 | % | 2008 to 2012 |
| Flotation circuit stages | Not stated | stages | One roughing, one cleaning, two scavenging |
| Reagents | Not stated | Not applicable | SBX, No. 2 oil, and lime added where required |
Overview
The Songjiagou Gold Project’s processing operations consist of three distinct plants, each with its own capacity and feed source. The 200 tpd plant is dedicated to underground ore, while the 1,200 tpd and 6,000 tpd plants handle open pit material. The open pit processing plants share a common flowsheet design, beginning with grinding followed by spiral classification. The classified slurry enters a flotation circuit configured with one stage each of roughing and cleaning, and two stages of scavenging. The flotation stage produces a gold concentrate that is dewatered before being sent for metallurgical processing to recover the gold.
Key Process Stages
The grinding and classification stage prepares the ore for flotation. After grinding, the slurry is classified using spiral classifiers to achieve a target particle size of 50% greater than 0.074 mm. The classified material is then conditioned with flotation reagents before entering the flotation circuit.
The flotation circuit is the principal recovery stage. It is arranged with one rougher stage, one cleaner stage, and two scavenger stages. The collector sodium butyl xanthogenate (SBX) is added to the flotation circuits, along with No. 2 oil as frother and lime for pH control, where required. Concentrates from the first and second scavenging stages are returned to the circuit as circulating load, while the tailings flow to the tailings pump station.
The gold concentrate from the flotation circuit is dehydrated before being sent for metallurgical processing. The metallurgical process involves regia digestion for gold analysis, though the specific recovery process for the concentrate is not discussed in detail in the available source material.
Reagent preparation and storage are carried out separately for each reagent. Slurry pumps are used to deliver lime slurry from the preparation area to the addition points in the flotation circuits.
Additional Interesting Data and Summary
The tailings storage facilities consist of multiple dams located south of the processing plants. One of the tailings dams has been operating for two years, while one other tailings facility has completed its service life and one is abandoned. Based on the Songjiagou Project’s designed processing capacity of 2,850 tpd, the life of the currently operating tailings dam is expected to be 10.2 years. However, based on the average processing capacity of 5,039 tpd after May 2011, the life of this tailings dam is expected to be reduced to about five years. The technical report concludes that the existing tailings storage facility capacity is inadequate and recommends an optimization study for tailings dam design and construction.
The processing plant water supply system includes a backwater tank system. The supernatant liquor from the tailings thickener overflows into the backwater tank, from which it is pumped to the water tank in the processing plant for production use.
Key Processes
- Grinding and spiral classification to 50% >0.074 mm
- Flotation circuit with one roughing, one cleaning, and two scavenging stages
- Flotation reagent addition using SBX collector, No. 2 oil frother, and lime
- Scavenger concentrate return to the flotation circuit
- Gold concentrate dewatering and delivery for metallurgical processing
- Tailings disposal to storage facilities with backwater recovery
Source: Songjiagou Gold Project , 2013 Technical Report, 2013.
Editorial Note: The source material contains a discrepancy regarding the tailings dam life expectancy. One statement indicates a life of 10.2 years based on a designed capacity of 2,850 tpd, while another statement indicates a life of about five years based on an average processing capacity of 5,039 tpd after May 2011. Additionally, the processing capacity figures of 2,850 tpd and 5,039 tpd used in the tailings dam assessment do not correspond directly to the 7,400 tpd total plant capacity reported elsewhere in the document.
Project website: Songjiagou Gold Project, 2013 Technical Report
