|Parys Mountain - A Special Place|
Extracts from a 1991 Leaflet
These extracts are taken from a leaflet on Parys Mountain prepared in 1991 by Anglesey Mining plc. They provide bits of additional information on the Mountain itself and on the company at that time.
The history of Parys Mountain mining activity is obscure prior to 1750, although there is evidence of mining as far back as Roman times. There is also evidence of Celtic mining and attempts to precipitate copper from mine waters by the Elizabethans in 1579.
A period of exploration occurred between 1750 and 1768 when Thomas Rose lead a team which discovered the Great Golden Venture Lode in the Parys Mine area. Within 5 years there were an estimated 1,500 men employed there hand working the open pit excavations which can be seen today. Smelters were first constructed in 1778 to upgrade poorer ore, consuming some 30,000 tons of coal annually. High grade ore was shipped directly to other smelters. Open pit mining finished during the early 1800's and was replaced by small-scale underground mining at the Mona Mine in 1811. A major expansion of underground mining in 1830 resulted from the discovery of the North Discovery Lode.
As the workings deepened, pumping became essential and a fine Cornish enginehouse and windmill tower are legacies of the period, as are extensive copper and ochre pits dating from the 18th century. Old scrap iron was placed in the pits where it dissolved with the copper in the water remaining behind as a heavy sludge.
During the late eighteenth century the mines on Parys Mountain constituted the largest copper production area in the world, but by 1904 the mines had closed due to lower cost production elsewhere in the world. The total production of copper from the area during the period between 1768 and 1904 has been estimated at 3.5 million tons of ore, from which 130,000 tons of copper metal was recovered.
It is estimated that there are over 20 km of abandoned underground tunnels and 84 named shafts plus 20 other workings, over a vertical extent of some 300 meters.
The property lies within the Caledonian Tectonic Belt which consists locally of a folded sequence of Ordovician and Silurian volcanic and sedimentary rocks, approximately 480 million years old. These rocks were affected by a subsequent period of mountain building and the resultant geological structure at Parys Mountain is dominated by an east-west trending syncline.
Exploration using modern methods commenced in 1955 and was continued by a number of mining companies intermittently for 30 years. Most of the drilling prior to 1973 was directed towards the exploration for copper and the size and significance of the polymetallic copper-lead-zinc-silver-gold deposits was first recognised in 1978 with the discovery of a high-grade zone, later to be named the Engine zone, located at the western end of the Property.
This mineralisation is mainly of volcanic origin and occurs at or above the contact between the sedimentary and volcanic rocks. Exploration has identified several zones of mineralisation consisting of beds of massive sulphides containing varying proportions of zinc, lead and copper sulphides, as sphalerite, galena, chalcopyrite and pyrite, with silver and gold.
Some 145 drill holes have been completed on the property, amounting to 47,360 m of drilling and a potentially mineable reserve has been estimated at 4.8 m tonnes with an average grade of: 1.49% Copper, 3.03% Lead, 6.04% Zinc, 57g Silver/ton and 0.4g Gold/ton. This reserve is the target of the current (1991) shaft sinking operation.
Anglesey Mining plc has initiated a programme to develop Parys Mountain to a point of commercial production in two phases.
Phase I involved the drilling and blasting of a 500 metre vertical shaft and driving tunnels totalling 1000 m in length to intersect the mineralised zones at selected levels, so that the bulk samples can be collected for detailed metallurgical testwork. This lateral development included access to underground drilling stations and also the orebodies themselves. Detailed drilling and underground sampling enabled reserves estimated from surface drilling to be confirmed and provide the basis for mine and plant design. The current shaft development and planned lateral development have been designed, sized and located so that they fit in with the overall mine design and will become part of the future production facility.
Phase II will consist of the construction of a surface ore processing facility and further development of the underground mine and plant. It is estimated that this Phase will require further funding of some �25 million and will take eighteen months to complete. Thereafter Anglesey mining will be in commercial production.
Access to Parys Mountain is excellent by rail, road and sea. All necessary services and resources, including power supply, repair and maintenance facilities are located within a relatively short distance.
Mining, Processing and Selling
Access to the ore body will be by a series of tunnels from the shaft at appropriate levels. Conventional shrinkage or blasthole stoping methods will be applied to extract the ore, providing the opportunity for low cost, high tonnage production.
The ore will be transported to an underground crusher station and then brought to the surface where it will be fed into the grinding mills of a concentrator plant constructed on the old mine site. The valuable minerals will be recovered from the pulp by a froth flotation process, yielding concentrates of copper, lead and zinc materials. The barren rock left after the separation process will be placed in tailings dams constructed on the old ochre pits to the south of the mountain. The concentrates will also contain silver and gold which are normally sold to smelters as an integral part of the base metal concentrates.
Shaft sinking operations have created 45 jobs in the immediate area and Phase II construction work will create a further 50 to 100 vacancies. At full production the mine will employ between 150 and 200 people.
Shaft sinking and development work has been contracted to Cementation Mining Ltd, with the day-today management being undertaken by the Mining Director and staff based at Amlwch. Further management services and support are provided by Anglesey Mining's parent company, Imperial Metals Corporation. Technical services are provided by the Robertson group and other consultants.
Anglesey Mining has planned its development programme giving careful attention to environmental, historical and archaeological concerns. An ongoing environmental monitoring programme has already commenced.
The Company has in conjunction with Gwynedd County Council and Ynys Mon Borough council recently waymarked all public footpaths on the mountain with coloured stakes. Further public access to archaeological and historical areas of interest on Parys Mountain is planned through the establishment of a series of additional discretionary footpaths and viewing platforms overlooking the Opencast working and other sites of interest.
The Renaissance of Parys Mountain
After 4 years of exploration and drilling, and successful public launch in May 1988, Anglesey Mining plc, a subsidiary of Imperial Metals Corporation of Vancouver, has now commenced an extensive mine development programme at Parys Mountain.
The first stone of the shaft sinking operation was turned on the 11th of October 1988 and the sinking hoist was commissioned in December of that year.
By the end of 1990 on the completion of Phase I the shaft had been sunk to a depth of 300 metres and over 100 m of underground development tunnels had been completed.
From these tunnels diamond drill holes further delineated the ore zones and bulk samples were taken for processing plant evaluation and design.
In Phase II the shaft will be deepened to over 400 m before driving further tunnels for mineral extraction. During this phase mill construction will commence on the old mine site and an onsite disposal facility will be built on the south side of the mountain.
On successful completion of the four year two stage development programme the Parys Mountain operation will be the most significant base metal producer in the UK, with a considerable economic impact on employment and business in the Anglesey area.
|Parys Mountain - A Special Place|
|Anglesey Mining plc
Parys Mountain, Amlwch,
Anglesey, LL68 9RE, UK
|Phone +44 1248 361333