Name of the Mine
Caijiaying mine.

Location  
North-west of Beijing in Hebei province, China.

Mine Owner/s  
Hebei Hua Ao, a joint venture between Griffin Mining (88.8%) and Zhangjiakou Yuanrun Enterprise Management Consulting Service Company (11.2%).

Brief Description  
The Caijiaying mine is an operating zinc, gold, silver and lead mine.

Numerous upgrades to the mine have been undertaken since commissioning, leading to the current nameplate mill throughput capacity of 1.5-million tonnes of ore a year.

With the granting of a new mining licence in December 2020 over the combined Zone II and Zone III areas, an application was subsequently made for the approval of a mine design for the new Zone II area. This was granted in March 2023. This will enable sustained production of at least 1.5-million tonnes of ore a year to be extracted from the Caijiaying mine until 2050, if not longer.

Brief History  
Griffin successfully commissioned the Caijiaying mine on time and within budget in 2005. 

Primary Metals/Minerals  
Zinc and lead.

Secondary Metals/Minerals  
Silver and gold.

Geology/Mineralisation  
The local geology comprises Early Proterozoic granulite and gneiss with marble lenses, which is unconformably overlain by the Late Jurassic Baiqi and Zhangjiakou formations. Porphyry sills and dykes intruding along faults have then cut across the sequence.

The mine’s deposits consist of zinc/gold/silver/lead orebodies hosted in a Paleoproterozoic inlier, comprising a mixed sequence of amphibolite-grade metavolcanic and metasedimentary rocks intruded by three generations of Jurassic porphyry dikes and sills.

The mineralisation comprises sulphide (sphalerite with lesser pyrite and minor galena) lenses that favourably replace units within the folded 2.3-billion-year-old metamorphic basement rocks. The base metal and gold mineralisation are similar with a skarn-type deposit. Mineralisation lenses up to 15 m thick dip steeply to moderately west and extend along strike and down dip tens to hundreds of metres.

Reserves  
Not stated.

Resources  
The Caijiaying mine’s mineral resource estimate comprises Zones II, III, V and VIII.

Total mineral resources as at February 2022, were estimated at 99.7-million tonnes grading 3.8% zinc, 0.6% lead, 0.5 g/t gold and 27.2 g/t silver.

Type of Mine
Underground.

Mining Method  
Caijiaying is being mined using longhole open stoping, cemented backfill, paste backfill and hydraulic backfill methods.

Major Infrastructure/Equipment  
The mine includes a processing plant, camp and supporting facilities, significant water supplies, two 35  kV power lines connected to the electricity grid, full connectivity to fixed and mobile telecommunications systems and broadband access for Internet services.

Prospects  
The Caijiaying mine’s metal production capability has been extended with continued extensive exploration, expansion of the mill processing facilities, including grinding and flotation circuits, and continuing underground infrastructure development.

Exploration has been focused on identifying geological targets and evaluating the potential for significant additional resources. This includes:

• exploration below the 1000RL at Zone III,
• the resource drilling in Zone II,
• further exploration at Zones V and VIII,
• exploration drilling out to the far eastern boundary of the Caijiaying mine’s mining licence area, and
• the possibility that virgin exploration tenements will be granted over other areas.

Contact Details
Griffin Mining
Tel +44 20 7629 7772

Sources
Griffin Mining. Website: http://www.griffinmining.com/
Griffin Mining. Website: New total global mineral resource statement (February 18, 2021).
Griffin Mining. Annual Report & Accounts 2022 (May 9, 2023).
Mining Data Online. Website: https://miningdataonline.com