geology · 1. 250k bedrock geology map 2. the sperrin mountains 3. geological map of the northwest...

1. 250k bedrock geology map2. The Sperrin Mountains3. Geological map of the Northwest4. The Mourne Mountains5. Geological map of the Southeast

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Northern Ireland represents one of the most complex and varied areas of geology in the world. The oldest rocks are Mesoproterozoic (c. 895Ma) and are succeeded by rocks representing every Phanerozoic system with the possible exception of the Cambrian. This diverse geological foundation has resulted in an equally diverse mineral heritage. Historical mining focussed on the production of iron ore, coal, lead and salt. However, since the 1970s potentially economic deposits of gold and lignite, and a variety of other minerals, have been identifi ed.

The bedrock geology map of Northern Ireland can be divided into quadrants, each with unique geological characteristics and mineral prospectivity.

The NorthwestThe northwest quadrant is underlain by the oldest rocks in Northern Ireland which belong predominantly to the Proterozoic Dalradian Supergroup and the early Ordovician Tyrone Igneous Complex. The Dalradian rocks are prospective for precious metals and host both the Curraghinalt and Cavanacaw gold deposits. The Middle Dalradian consists of metamorphic rocks which were originally deposited as sediments with minor submarine volcanics at the southern edge of the Laurentian continent in a tectonically unstable marine basin prior to the opening of the Iapetus Ocean (700–600Ma). The succeeding Upper Dalradian consists mainly of turbidites deposited in an unstable outer shelf environment. The Iapetus Ocean attained its maximum extent during the Cambrian when it would have resembled the present day Atlantic Ocean. Subsequent closure ensued during the Ordovician and early part of the Silurian and was accompanied, in the early stages by the Grampian Orogeny (475–465Ma). All the sedimentary rocks deposited in the Iapetus Ocean were deformed in the late Silurian and early Devonian during the Caledonian Orogeny (425–400Ma). Much of the gold mineralisation is believed to be associated with tectonism, and in particular thrusting. However, some mineralisation is also associated with

the Variscan Orogenic Cycle. A number of long-lived lineaments may have also played a role in the localisation of the gold-bearing fl uids and studies of their wider implications are continuing. Other mineralised localities in the northwest quadrant require further exploration before their genesis is properly understood.

The Tyrone Igneous Complex lies southeast of the Dalradian outcrop and comprises the Tyrone Plutonic (TPG) and Tyrone Volcanic (TVG) Groups. The basal TPG represents the upper part of an early Ordovician ophiolite and has the potential to contain chromite and PGM deposits. It was obducted during the Grampian Orogeny onto the southern edge of the Laurentian continent. The structurally overlying TVG is interpreted as representing an island arc and is the easterly extension of the system that hosts mineralisation in the Buchans District of Newfoundland. Acid intrusions in the TVG have also proved prospective for porphyry copper-style mineralisation.

The SoutheastThe southeast quadrant is composed mainly of rocks of the Southern Uplands-Down-Longford terrane. The terrane is an allochthonous prism composed of an Ordovician and Silurian turbidite sequence comprising greywacke sandstone, siltstone and mudstone. The rocks consist of siliciclastic material that was deposited in the Iapetus Ocean. As northwestward subduction of the oceanic plate proceeded, packets of these sediments were accreted onto the Laurentian continental margin as a growing stack of underthrust slices. Each packet of sediment is bounded by major faults that defi ne individual tracts. Large scale sinistral strike-slip movements occurred on these faults which are directly related to base metal mineralisation. The rocks host the lead mines in Counties Armagh and Down which operated in the 19th century. Gold exploration programmes are targeting these faults as conduits for mineralising fl uids.

The sediments are intruded by granitoid bodies of which the oldest is the

© Crown Copyright 2008, OSNI Permit No. MOU205

Geology

1. Landsat image of the Northeast2. Co. Fermanagh3. Geological map of the Southwest4. The North Coast5. Geological map of the Northeast

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predominantly silicic late Caledonian Newry Igneous Complex (400Ma). This is itself intruded by the early Palaeogene Slieve Gullion Complex (c. 58Ma). In south Co. Down the Palaeogene Mourne Mountains Complex comprises fi ve intrusive phases of granites and developed a contact metamorphic aureole up to 1km wide. The mineral potential of this area (in particular REEs) remains to be fully explored and the source of alluvial gold found in streams draining the intrusive complexes is still elusive.

The SouthwestThe southwest quadrant is underlain mainly by Upper Palaeozoic sedimentary rocks. The fault-bounded Fintona Block consists of Early Devonian and Lower and Upper Carboniferous red beds and volcanic rocks. Surrounding Carboniferous (350–300Ma) rocks commence with a thin continental sequence but the remainder were deposited in a predominantly marine environment which varied from shallow water carbonate platform and deltas to deeper water basinal mudstone and carbonate facies. The Lower Carboniferous limestones are host to the Irish Midlands zinc province and targets have been generated in Co. Fermanagh that remain to be fully evaluated.

The Upper Carboniferous comprises a cyclical sequence of largely deltaic sediments which also include signifi cant coal seams. These were worked until 1967, but are now considered uneconomic.

The NortheastThe northeast quadrant is mostly underlain by the early Palaeogene (60–55Ma) Antrim Lava Group. However, the earliest eruptions were violent and formed localised rhyolitic volcanoes in central parts of Co. Antrim. Within the Tardree Rhyolite Complex, the largest area of silicic volcanic rocks, is a signifi cant deposit of perlite which remains to be fully explored. The main basalt lavas were then erupted in two main cycles separated by a period of relative quiescence when deep weathering of the lower basalts

occurred in a warm wet climate and produced a conspicuous and thick layer of reddish lateritised basalt known as the Interbasaltic Formation. This represents the primary source of iron ore and bauxite in Northern Ireland and throughout a long history of mining produced some 5Mt. There is still small scale production of bauxite which is used as feedstock for the production of ferrous aluminium sulphate, a water purifi cation material.

Since the eruption of the lavas, they have concealed and protected from erosion a Permian to Cretaceous sequence of softer rocks. These crop out at the margins of the Antrim Plateau but have been investigated more thoroughly in deep boreholes. In late Palaeogene (Oligocene) times (25Ma) localised non-marine basins which formed on top of the basalt plateau were fi lled mainly by deposits of lacustrine clay but also developed very thick beds of lignite at their margins. Exploration of the Oligocene clay basins has revealed the presence of three large deposits containing about 1 billion tonnes of lignite.

In southeast Co. Antrim the Triassic (248–206Ma) rocks contain thick beds of halite (rock salt). This was historically mined at several locations but is now only worked by the room and pillar method at one mine producing about 500,000 tons per annum which is mainly used for gritting roads in the UK, Ireland and the USA.

The GSNI has recently published The Geology of Northern Ireland - Our Natural Foundation. This publication is based on the 1997 1:250,000 geological map. In 2007, The Last Glacial Termination in Northern Ireland was published in association with the University of Ulster.


Geology (cont’d)

1. Gold panning2. Gold in polished section, Curraghinalt3. Alluvial gold grains4. Underground at Curraghinalt5. Ore from Cavanacaw

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Gold has been valued for thousands of years. In addition to its common uses in jewellery and monetary standards, it is also used in the dental, electroplating and scientifi c industries. Silver has also been prized for centuries and was widely used in coinage. Nowadays it has many uses including jewellery.

Gold & Silver in Northern IrelandNorthern Ireland is arguably the most prospective area of the United Kingdom and Republic of Ireland for precious metal deposits. Alluvial gold has been recovered from parts of the country since Celtic times when it was used to produce ornate artefacts. Modern-day exploration commenced in the late 1970s. The GSNI has been involved in several different regional geochemical and geophysical programmes that have greatly assisted in target selection and these data sets have been used by many commercial companies to defi ne licence areas. At present two main areas are considered to have the highest prospectivity for precious metal deposits, although as further data are collected and new models developed other areas may become targets.

The SperrinsThe Sperrin Mountains of Counties Tyrone and Londonderry have been the most important historic alluvial gold producer, as well as the most explored area in recent times. The results of the 1976 GSNI survey, over areas underlain by the Neoproterozoic Dalradian rocks (c. 590Ma), fi rst highlighted the auriferous potential of the region and in the early 1980s bedrock gold mineralisation in quartz veins was discovered in Curraghinalt Burn. Work has continued on the prospect, including 700m of underground development and the detection of auriferous veining at depth. The current estimate, includes an indicated resource of 570,000t grading 13.9g/t Au and an inferred resource of 640,000t grading 17.1g/t Au based on a cut-off of 6g/t Au and a minimum vein width of 1m. This represents an indicated and inferred resource of 600,000 ounces. Five kilometres to the west of Curraghinalt, the Golan Burn prospect was also discovered by diamond drilling.

About 20km to the southwest is the Cavanacaw deposit. Galantas Gold have developed the fi rst modern gold mine in the British Isles and have proven reserves of 180,000t grading 7.4g/t Au and probable reserves of 186,000t grading 7.7g/t Au. An indicated resource of 1,200,000t grading 7.0g/t Au also occurs within the mine lease area. Across the rest of the Dalradian in this area there are a number of showings and drill intersections suggesting that further economic resources remain to be identifi ed. In 1996, a gold metallogeny study of northwest Northern Ireland identifi ed a number of prospective areas as well determining the multi-stage history of gold mineralisation in the region.

Northeast Co. DownExtensive Au anomalies have been identifi ed in soils and stream sediments east of Belfast in the Holywood and Newtownards areas. These anomalies occur in proximity to the Orlock Bridge Fault, and the along strike continuation of this structure intersects Au anomalies near Keady in Co. Armagh.

Southeast Co. DownA soil gold anomaly has been identifi ed by Tellus geochemistry stretching from Warrenpoint to Kilkeel. Gold grains have been recovered in pan concentrate samples from this area. Recent studies of these gold grains indicate that they represent a distinctive group in the Southern Uplands-Longford-Down terrain.

Co. ArmaghAn extensive zone of anomalous Au in both soil and stream sediment samples confi rms gold prospectivity in the Keady area. Anomalies indicate possible association with the Orlock Bridge Fault and Lower Palaeozoic stratigraphy.

Other AreasAreas of the Sperrins and the nearby Tyrone Igneous Complex are considered prospective for base-metal stratabound, porphyry and VMS style deposits which locally may have precious metal enrichment.

The Dalradian inlier of northeast Co. Antrim exposes similar rocks to those found in the Sperrins and alluvial gold has been recovered from the area.

Precious Metals

1. Core store, Gortin2. Zn-Pb mineralization3. Drilling in the Sperrins4. Zn in soil 5. Historic mining

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The base metals of copper, lead and zinc form part of the base of today’s technologically driven society. Transport systems rely on these metals for the production of cars, aeroplanes and ships and the communications industry would never have reached its current level without the use of these metals in telephones, televisions, computers, satellites and cables.

Base Metals in Northern IrelandNorthern Ireland is one of the most prospective areas of the United Kingdom for base metal mineralisation. Historical production of lead has resulted in numerous small adits and shafts across parts of Counties Down, Armagh and Tyrone. Modern exploration commenced in the late 1960s, following the introduction of the Mineral Development Act (Northern Ireland) and continues to the present day. The GSNI has actively promoted exploration through the completion of a number of geochemical and geophysical surveys as well as a number of applied studies that have resulted in the production of a series of technical reports. At present three main areas are considered to have the highest prospectivity for base metal deposits. However, as further data are collected and new models developed other areas may become targets.

The SperrinsAlthough primarily of interest for precious metals, the Sperrin Mountains of Counties Tyrone and Londonderry also have the potential to host economic base metal deposits. Indeed the Glenlark prospect, only 3km from the Curraghinalt gold deposit is believed to represent a stratabound mineralisation system (Zn-Pb-Au-Ag). The results of the GSNI surveys over areas underlain by Neoproterozoic Dalradian rocks (c. 590Ma) have highlighted numerous areas which merit follow-up investigation and bedrock base metal sulphide mineralisation has been discovered at a number of localities throughout the region.

Tyrone Igneous ComplexThe Tyrone Igneous Complex to the southeast of the Sperrins comprises the Tyrone Volcanic Group, consisting of volcanic, volcaniclastic and thin sedimentary rocks representing three

volcanic cycles. The island arc setting of this Group makes it highly prospective for Volcanogenic Massive Sulphide-style deposits as well porphyry-style mineralisation associated with acid intrusive bodies, which has been identifi ed at Cashel Rock. Geologically, this area represents the eastern extension of the island arc that hosts the Buchans deposits in Newfoundland.

The CarboniferousThe Lower Carboniferous lithologies of Counties Fermanagh and Tyrone are considered prospective for carbonate hosted Zn-Pb-Ag deposits. Exploration in the 1970s identifi ed sub-economic concentrations of base metal sulphides and as a result of the GSNI geochemical surveys, part of the Clogher Valley was highlighted as an area with enhanced prospectivity. Outcrops of Waulsortian stratigraphy (host to the majority of deposits in the Republic of Ireland) remain to be fully evaluated.

Other AreasThe Dalradian inlier of northeast Co. Antrim exposes similar rocks to those found in the Sperrins and as such may represent a target for base metal mineralisation. Drilling through the Antrim Lava Group also identifi ed mineralised Dalradian bedrock at shallow depths.

The prospectivity of the basalts of the Antrim Lava Group for copper and nickel remains largely unknown, although native copper was drilled in basalts below the Ballymoney lignite deposit.

A number of anomalous areas have been highlighted in the south Co. Armagh region which are not believed to be related to the historic workings.

A belt of anomalous soil Zn values extends from the area of known gold mineralisation at Keady to the southeastern part of Co. Down. This anomalous zone occurs within the Lower Palaeozoic sediments. Historically these lithologies have been mined for base metals.


Base Metals

1. Brookeborough diamond2. Stream sampling 3. Geophysical surveying4. Co. Tyrone5. Tellus survey: magnetics

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Diamonds remain without question the worlds most sought after gemstone. The world jewellery market is demanding increasing numbers of high grade diamonds and the production of lower quality diamonds used in the industrial market remains robust. Given the profi tability of diamond mining it is unsurprising that the exploration sector continues to have a strong focus on diamonds.

Diamonds in Northern IrelandTo date no bedrock diamond source has been identifi ed in Northern Ireland and at present no companies are exploring for diamonds in the country. However, because diamonds have proved so diffi cult to locate, most discoveries in virgin territory have had a great deal to do with luck. This was the case in South Africa where the chance discovery provided the catalyst to the development of the world’s most successful diamond-mining economy. In 1995 the British Geological Survey reported that the potential for a diamond discovery in Northern Ireland is good.

Two reports from the Journal of the Royal Geological Society of Ireland refer to the 1816 discovery of the Brookeborough diamond in the Colebrooke River of Co. Fermanagh. The stone was presented to Lady Brooke and inspected by several jewellers in Dublin, who confi rmed the stone to be a diamond.

The CarboniferousInspired by the above accounts, a Canadian company licenced large tracts of Counties Tyrone and Fermanagh in 1996 to locate the source of the Brookeborough diamond. The work was concentrated on the Carboniferous and older rocks which may be underlain by Proterozoic/Archaean basement. The company identifi ed a number of target areas which which were the subject of regional large volume stream sediment sampling. In total, 158 samples were collected, comprising 30kg of sediment screened to minus 1.7mm on site. The results of this programme revealed over 400 potentially kimberlitic minerals in 28 of the samples. In summary, two

garnets were found and rated as high-medium diamond interest, 364 chromite grains were classifi ed as kimberlitic - one being rated as high interest and 273 rated as medium interest and one ilmenite analysis was also classifi ed as being kimberlitic. Independent consultants interpreted these results as suggesting the possible occurrence of high interest kimberlites within the area drained by the streams from which the samples were recovered. In 2000 the company surrendered its Northern Ireland licence block without conducting any further work.

The DalradianThe Inishowen Peninsula of Co. Donegal in the Republic of Ireland is underlain by similar Dalradian metasediments to north Co. Londonderry. In 1996 an exploration company began work on the peninsula. Airborne magnetic surveys were completed over the entire licence block and followed up by ground surveys over anomalous areas. In addition, a regional stream sediment survey collected 96 samples for heavy mineral analysis. This led to the identifi cation in 2000 of a potential bedrock source believed by the company to be a lamproite and a short drilling programme was completed. The possibility for other gemstones in the area has also been confi rmed with the discovery of micro and macro rubies and sapphires in Co. Donegal.

Diamonds

1. Tyrone Plutonic Group2. Gabbro under cross polars3. Platinum in soil4. Gabbro, Tyrone Plutonic Complex5. Palladium in soil

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Carrickmore(and quarry)

Scalp

Creggan

Tanderagee

CopneyMountfield quarry

Cashel Rock

Mweela More

Craiganawork

BF

BFBF

DF

DF

Beaghbeg

BlackRock

Lough FeaBonnety

BushBroughderg

FirMtn.

SlieveGallion

Tintagh

Pomeroy

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TYRONE IGNEOUS COMPLEX

Copney PillowLava Fm

TYRONE VOLCANIC GROUP

TYRONE PLUTONIC GROUP

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Llan

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Rhyolite

Quartz Porphyry (Porphyritic dacite)

Diorite

TonaliteLaght Hill Tonalite

'Granite'

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3 Slieve Gallion

Craigballyharky

CraigbardahessiaghPomeroyCarrickmoreBeragh

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456

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SouthernHighland Group(undivided)

Little River andDesertcreatgroups

post-Silurianrocks

Graptolitelocality

CorvanaghanFormationMoinian?

Dalradian

BeleevnamoreFaultDavagh Fault

Thrust Fault

Figure 3.1: Geological map of the Tyrone Inlier including the Central Inlier (Corvanaghan Formation) and Tyrone Igneous Complex.

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0 5km

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The Platinum Group Metals (PGMs) have been increasingly sought after in recent times as demand from high technology industries has outpaced supply. The result has been a dramatic increase in prices. In addition, new metallogenic models have led to an upsurgencein PGM exploration worldwide andthe identifi cation of new sources isnow essential.

PGM mineralisation in fl oat has been identifi ed in the Republic of Ireland (within the Palaeogene Carlingford Complex). Given the genetic relationship between the Carlingford Complex and the Slieve Gullion complex in Northern Ireland, it is also possible that PGM mineralisation could be present here.

Antrim Basalt PlateauNew areas for PGM exploration have been identifi ed using Tellus geochemistry in northwest and east Antrim where extensive anomalies for Pt and Pd occur in both soils and stream sediments. Most of these anomalies are associated with lineaments delineated by the Tellus geophysical dataset. Many of the PGM anomalies have coincident gold anomalies in soil and stream sediment

Sperrin MountainsNew soil and stream sediment anomalies for both Pt and Pd have been identifi ed in the Sperrin Mountains. These anomalies indicate potential prospectivity and a possible stratigraphic correlation to source rocks.

Omagh Thrust ZoneA zone of Pt anomalies to the southwest of the town of Omagh are spatially related to the Omagh Thrust zone. To the southwest of Lower Lough Erne, soil Pd anomalies occur along the strike extension of the Omagh Thrust.

The Dromore Gravity HighThe centre of the Dromore gravity high is located less than 20km from the southwest end of the Tyrone Igneous Complex and lies directly along the regional strike. Two theories about the source of the geophysical high have been put forward. The more favoured theory is that it represents the along

strike extension of the Tyrone Igneous Complex, although it has also been argued that it represents a buried dioritic intrusion. In addition, a broad PGM anomaly was identifi ed from streams draining the area. Further work is necessary to identify the geological feature responsible for the geophysical and geochemical anomalies and to this end, the fi rst licence in Northern Ireland for PGM mineralisation was issued over the Dromore gravity high in 2003.

The Tyrone Plutonic GroupThe Tyrone Plutonic Group (TPG) represents the remains of an ophiolite obducted on the Laurentian foreland during the Caledonian Orogeny. The Group was not identifi ed as part of an ophiolite sequence until 1985 and since then no serious attempt at PGM exploration has been undertaken, although some desktop studies were completed in 1986. Using analyses from three samples taken from the country rock contact, it was concluded that the original magma was capable of producing economic concentrations of PGMs. In terms of an exploration guideline it suggests targeting the lower ultramafi c portions of the Group as well as any areas containing podiform chromite mineralisation. Developments in exploration thinking and technology since 1986 mean that the potential of the TPG deserves to be re-examined.

Other AreasTellus geochemistry has identifi ed new localities for PGM investigation; these include (i) west of Londonderry, (ii) Rosslea in Co. Fermanagh and (iii) in Co. Down where Pt anomalies show correlation with lineaments.


PGMs

1. Moune Mountains2. Exposure in quarry3. Veining on County Down Coast4. Pegmatite5. Magnetics, Slieve Gullion

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Demand for Rare Earth Elements (REEs) and tantalum continues to grow in line with our demands for smaller electronic technology and increased performance. For example, in 2000 tantalum experienced a 33% price increase. Whilst this trend has slowed in recent years, future long-term demand growth expectations remain between 10–20% per annum. Some of this increased demand will be taken up by expanded operations and recently discovered deposits but exploration interest remains strong worldwide as new uses for REEs are developed.

REEs in Northern IrelandCurrently no REE deposits have been discovered in Northern Ireland but a number of grass roots opportunities exist for explorers with experience in this particular sub-sector. One of the classic geological environments for REE deposits to form is in pegmatite veins, near to the edges of large acid intrusions that have cooled slowly within the earth’s crust. This allows for the development of late stage fl uids that can concentrate the REEs and certain other minerals (including tantalum and lithium). If the pegmatite size and density is great enough an economic deposit may be formed. There are three main acid intrusive centres in Northern Ireland that could be considered prospective for REE mineralisation.

The Mourne MountainsIn the late 1970s a limited amount of exploration work was completed but this focused on uranium and tin mineralisation. As such the REE potential of the Mourne Mountains complex has never been properly evaluated, but given the common association of Sn and U with REE deposits, the area can be considered geologically prospective. Radiometric and stream sediment surveys were completed and a number of coincident anomalies in the south and eastern Mournes were identifi ed. Overall, the Mourne Mountains complex proved to have the highest background radiometric values of all the Irish intrusives but it was the tin anomalies that were followed-up. Bedrock cassiterite in quartz veins cross-

cutting the granite was identifi ed at the intersection of two fracture sets with values up to 0.4% Sn over 0.3m. No REE values were analysed.

Some of the most extensive Nb, Ta, and Yb anomalies occur in the soils of the Mourne Mountains.

Slieve GallionThree of the REEs were analysed as part of the regional geochemical survey of the western half of Northern Ireland. Very similar patterns were produced for cerium, lanthanum and thorium with strong but possibly formational anomalies located over the extreme west of Co. Tyrone. Perhaps more interestingly, anomalies also occur over the Slieve Gallion complex and parts of the Tyrone Igneous Complex. Given the prospective geological environment in these two regions follow-up work is merited. Although not a REE, the uranium pattern is also of interest, showing similar anomalies centred over the southern edge of Slieve Gallion.

The Newry ComplexThe late Caledonian Newry intrusive complex is a multi-pulse intrusion similar in age and style to the Leinster Intrusion in the Republic of Ireland. Both intrusions resulted from crustal melting at the roots of the mountain range formed by the Caledonian orogeny and are dated at around 400Ma. Exploration in the Republic of Ireland has identifi ed pegmatites up to 20m thick by 400m long containing 1.6% Li and accessory tin, niobium and tantalum. Although values for the REEs sensu stricto have not been recorded, the metal association increases the REE prospectivity. In Northern Ireland, radiometric anomalies believed to be related to uranium mineralisation were identifi ed over areas of the Newry complex during the late 1970s work.

Other AreasThe Tellus geochemistry program has identifi ed anomalous concentrations of Nb and Th in soils on Dalradian metasediments of the Claudy and Ballykelly Formations in Co. Londonderry.


REEs

1. Crumlin2. Exploration at Crumlin3. Lough Neagh Clay Group4. Exploration at Ballymoney5. Lignite at Craigahullier

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Solid fossil fuels such as coal, lignite and peat remain one of the world’s major sources for power generation and electricity remains one of the world’s most valuable commodities. Reports of recent energy crises and predictions of similar events in the future have encouraged a number of companies to explore for new sources of fossil fuels.

Fossil Fuels in Northern IrelandNorthern Ireland has deposits of coal, peat and lignite. Historically, hard coal has been extracted extensively although the last commercial operation closed in 1967. Two Upper Carboniferous coalfi elds located in east Co. Tyrone and northeast Co. Antrim were worked for (sub-) bituminous high volatile coal. Unlike in the Republic of Ireland, peat is only worked on a small-scale basis by individuals or small co-operatives to burn in their homes.

The greatest potential for future indigenous production and power generation comes from Northern Ireland’s signifi cant lignite resources, estimated at over 1 billion tonnes. The existence of lignite in the Oligocene Lough Neagh Group has been known since 1757. However, it was not until the GSNI initiated drilling programmes in the late 1970s and mid-1980s that the true potential became apparent. Three separate deposits were outlined at Ballymoney, Crumlin and Coagh. In 2007, DETI renewed a moratorium on the issue of lignite prospecting licences. This will be assessed again in 2010.

BallymoneyThe Ballymoney deposit is located 40km northeast of Lough Neagh and contains the largest resource at 700Mt. The lignite occurs as a number of seams to the north of a major fault within a sequence of sandy clays and silts. The seams can be tens of metres thick, but generally thin and split towards the margins of the palaeo-basin.

CrumlinThe Crumlin deposit is located on the eastern shores of Lough Neagh and substantial lignite resources are known to exist below the lough. The lignite occurs in two seams in a fault-bounded basin, dipping below the lough. Although the onshore deposit is smaller than Ballymoney, there are still enough resources to supply a mine-mouth power plant for 20 years. The prospect is still under development and the current licence holders are looking into all potential uses for lignite.

CoaghThe Coagh lignite deposit is located on the western shores of Lough Neagh and is the least developed at present. Substantial resources also exist under the lough.

Other AreasOther areas underlain by the Lough Neagh Group (principally to the south of the lough) have yet to be fully evaluated although lignite has been discovered here.


Fossil Fuels

1. Cottonmount Quarry2. Hardrock quarrying3. Mount Prospect sand and gravel pit4. Quarrying in Co. Tyrone5. Sand and gravel extraction

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Aggregates or construction materials quite literally form the building blocks of modern industrial society. Construction projects rely on locally available sources of aggregate for concrete production and our entire transportation network would not exist without the input of local materials. In addition, aggregate products are also used in water treatment plants and drainage/sewerage systems and specialised aggregates are necessary for the chemical industry.

Aggregates in Northern IrelandAs a result of its varied geology, Northern Ireland has a diverse aggregates base upon which the construction industry has developed. In 2006, there were 137 active quarries and pits extracting material primarily for the local market. A total of 1,584 people were employed in the industry and it produced 25.7Mt of material valued at £88.8 million. The primary products extracted include sand and gravel, basalt, sandstone (including greywacke) and limestone. Most quarries are operated by family-owned businesses, but a number are larger and part of multi-national companies.

Sand and GravelSand and gravel deposits formed at the end of the last ice age between 10,000 to 13,000 years ago. As the glaciers began to melt, the material they had eroded was transported into large glacial lakes where it was deposited to form the typically well-sorted fl uvio-glacial deposits that characterise the Northern Ireland landscape today. In 2006, Northern Ireland produced over 5Mt of sand and gravel primarily for use in the building industry.

LimestoneLimestone deposition occurred at three main times during Northern Ireland’s geological past. The oldest Dalradian limestones have all been metamorphosed to marble and may have dimension stone potential. The most widespread limestones formed during the Lower Carboniferous in Co. Fermanagh. The youngest limestones are a special variety known as chalk and produce a very high purity product. Limestone is quarried

for uses in the production of concrete as well as the agricultural industry. Minor occurrences of high magnesium (dolomitic) limestone are quarried to counteract magnesium defi ciencies in livestock. In 2006 over 5.6Mt of limestone was extracted.

BasaltThe basalts of the Antrim Lava Group are worked for their aggregate potential, particularly within the road building industry. As a typically uniform, fi ne-grained, hard, dark rock it has many of the properties necessary for use in the transportation network. In 2006 over 6.8Mt of basalt was produced from well-situated quarries, mostly in Co. Antrim.

SandstoneSandstone includes the Silurian greywackes (or gritstone) of Counties Armagh and Down. These have high polished stone and aggregate abrasion values, making them a particularly good source of wearing course aggregate. In 2006 Northern Ireland produced over 6.9Mt of sandstone mostly for use in the roads industry.

OthersA number of other commodities are extracted from quarries in Northern Ireland, including granite from the Mourne Mountains in Co. Down, schist from the Mesoproterozoic in Co. Tyrone and slate from the Lower Palaeozoic rocks of Counties Armagh and Down.

Aggregates

1. Salt mining at Carrickfergus2. Underground at Kilroot salt mine3. Perlite4. Diatomite5. Bauxite mining

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Whilst not being as well known as gold or diamonds, industrial minerals form the backbone of modern society. As any economy continues to grow, the need for these minerals will increase. Many industrial minerals have a variety of different uses making them an attractive mining proposition as they tend to be less sensitive to cyclical market trends.

Industrial Minerals in Northern IrelandNorthern Ireland has a remarkable variety of industrial minerals, many being present in workable amounts capable of contributing to the economy. Five different commodities are discussed here, but please contact the GSNI to learn more about different minerals.

SaltBedded halite in the Triassic Mercia Mudstone Group underlies the area between Carrickfergus and Larne and has been worked for over 100 years. Until 1958, rock salt was produced from a number of underground operations and brining was often employed. In 1965 a new mine commenced production at Kilroot, operated by the Irish Salt Mining and Exploration Company Ltd. Access is via a decline and mining is by the room-and-pillar method. Each year up to 500,000t of salt is produced and processed on-site before being sold to the winter road maintenance markets in the UK, Ireland and the USA. Within the mine area, the salt beds vary in thickness from 9 to 27m and occur at fi ve separate levels. However, 15km to the north a drillhole intersected 400m of Triassic halite in three seam groups as well as 113m of halite in the older, deeper Permian Upper Marls.

BauxiteBauxite was formed by lateritisation of the basalts of the Antrim Lava Group, producing the Interbasaltic Bed between the two main lava formations. The Antrim bauxite is a residual clay deposit and is very variable in composition, with samples up to 62% Al2O3 and low silica. On a world scale the Antrim bauxites are not economic, but the ceramic and other properties remain to be fully investigated. Where the Interbasaltic

Bed outcrops in basalt quarries, it may be economic to work the bauxite on a small scale as at Clinty Quarry in Co. Antrim. The bauxite is processed to produce aluminium ferric sulphate which is used in water treatment plants and sewage works.

PerlitePerlite is the industrial name for volcanic glass. Explosive volcanic activity at the beginning of the Palaeogene led to the formation of a volcanic diatreme near Sandy Braes, Co. Antrim. The deposit occurs within the Tardree Rhyolite Complex which formed within the vent. Following minor trial work in the 1940s the deposit remained untouched until the mid-1980s when planning permission was granted to develop an extractive facility. Perlite has a variety of uses and forms an inert, lightweight and porous granular product used in construction materials, fi ltration systems and agriculture.

GypsumGypsum for use in the building plaster industry has been mined from the Permian rocks of Co. Cavan since 1937. Similar rocks occur in Northern Ireland and gypsum was found in the Upper Marls below east Belfast. Signifi cant quantities of gypsum and anhydrite have also been intersected in mineral exploration boreholes drilled through the Lower Carboniferous of Co. Fermanagh.

DiatomiteDiatomite occurs as a 0.9m thick deposit north of Lough Neagh and was worked until the late 1960s. It forms a chemically inert powder that can be used as a fi ller in paint, plastic and rubber manufacture and also in the food and pharmaceutical industries.

Industrial Minerals

1. Laganside redevelopment2. The Crown Bar, Great Victoria Street 3. Harland & Wolff shipyard4. Royal Avenue and City Hall, Belfast

Photographs courtesy of the Belfast Visitor and Convention Bureau.

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Northern Ireland offers great opportunities to the mineral explorationist. It combines all the convenience of working in a developed world country with a tremendously diverse geological and mineral heritage and a history of mining dating back centuries.

The true potential of Northern Ireland has only become apparent over the last few decades and large areas of prospective terrane remain under-explored and some even unlicenced. New geological thinking is being used to re-evaluate areas previously considered less prospective. Although Northern Ireland is one of the smallest countries in Europe, it has a mineral potential to rival any of its near neighbours.

HistoryThe fi rst thing people still think about when they hear the words ‘Northern Ireland’ is ‘The Troubles’. However, the last ten years has been a time of remarkable progress in Northern Ireland. An end to almost all civil unrest has been accompanied by a new, more inclusive political climate. In 2007, the power-sharing, devolved Assembly assumed the government of Northern Ireland and local Ministers now head-up the eleven departments. The Department of Enterprise, Trade and Investment has placed economic development at the centre of government policy.

Belfast is now one of the fastest growing cities in Europe and revitalisation continues apace. The views expressed by many of the growing numbers of tourists visiting Northern Ireland are generally of pleasant surprise at the beautiful countryside, friendly people and relaxed atmosphere.

GeographyNorthern Ireland has a total landmass of 14,148km2 and is approximately 140km long by 175km wide. Situated in the northeast Atlantic, it has a mild temperate climate infl uenced by the North Atlantic Gulf Stream - temperatures typically average 5°C in winter and 15°C in summer. Average annual rainfall is 1000mm per year,

with the western half of the country being slightly wetter and cooler. As such, it is possible to actively explore all year round.

PeopleThe population of Northern Ireland is 1.7 million with the capital city of Belfast being the main population centre. Other regional population centres outside the Greater Belfast area include Londonderry, Newry and Omagh. The population is mainly concentrated in the two easternmost counties, with large areas of the west of the country relatively sparsely populated.

One of Northern Ireland’s strengths is its people. Renowned for their hospitality and love of ‘the craic’, Northern Ireland has a young, highly educated, innovative population. Companies can draw on all the necessary exploration and mining skills from Northern Ireland, the Republic of Ireland and Great Britain.

CommunicationsNorthern Ireland has one international and two regional airports (with direct routes to Europe and North America), a rail network undergoing modernisation and a good road network, which has been improved in the recent past (you can drive from Belfast to anywhere in the country in less than two hours). Northern Ireland is also served by four deep-water ports, ensuring ease of access to international markets. Northern Ireland’s telecommunications network rivals that of any other European country with continuous upgrades ensuring reliable, high-speed links to the rest of the world.

Northern Ireland

1. North Coast railway2. Sperrin Mountains3. Port of Belfast4. Belfast Port viewed from Cavehill5. Giant’s Causeway

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The Northern Ireland government recognises the great benefi ts that can be brought about by responsible development of its indigenous mineral resources. This commitment is refl ected in the transparent legislation and the pro-active role adopted by DETI and is the driving force behind this new Mineral Promotion Strategy.

Fiscal IncentivesNorthern Ireland offers unique tax advantages including rapid write-off of fi xed assets and zero property taxes.

For manufacturing businesses, tax-free capital grants on new buildings and machinery is tax free up to 45% of the asset cost. Companies can therefore calculate their tax depreciation allowances at the full cost of the asset.

Depreciation Allowances are calculated at 25% per annum (reducing balance) for machinery and at 4% per annum (straight-line) for industrial buildings.

Property Taxes for manufacturing property are zero.

Research & Development (R&D) mean that companies can write off all their capital spending on R&D against income. R&D tax credits have also been introduced for smaller companies and it is proposed to extend this to larger fi rms.

The levels of corporation tax in Northern Ireland are among the lowest in the EU.

The UK has the lowest ‘top rate’ of personal taxation in the EU and a starting rate of just 10% for most sources of income.

InvestNIIt is recommended that any prospective operator establish contact with InvestNI (an agency within DETI) who can provide information on the different types of incentives and grant aid that may be available. The InvestNI website can be accessed at www.investni.com.

Pragmatic Environmental LegislationWhilst recognising the need for environmental controls, DETI has adopted a pragmatic policy which ensures best environmental practice whilst not affecting the viability of exploration work on the ground. When projects reach the development stage a detailed Environmental Impact Assessment is required.

Ease of ExplorationLogistically, exploration in Northern Ireland is also a relatively easy task. The temperate climate ensures that work can be conducted across the country all year round. In addition, Northern Ireland has a fully developed and integrated transport and communication network, with no point in the country more than 80km from a major port. Northern Ireland’s diverse service sector also ensures value for money at all stages of the exploration and mining cycle. It can offer a highly educated, young workforce, keen to innovate and push the boundaries of technology.

Incentives

1. Colby House2. Underground at the salt mine3. Maidenmount salt mine collapse4. Maidenmount salt mine restoration5. Ground under license and application

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The legislation governing exploration and mining in Northern Ireland is regulated by the Department of Enterprise, Trade and Investment (DETI) through its Minerals Branch. DETI was one of 11 government departments created after the devolution of power from London to Belfast in 1999 and the creation of the Legislative Assembly.

The new system of linked-up government created by devolution brought the different government departments closer together and DETI now works closely with the Department of the Environment on minerals-related matters. DETI is also responsible for InvestNI, the government agency charged with attracting inward investment to Northern Ireland, as well as the Health and Safety Executive.

Key PersonnelDETI has three staff within Minerals Branch. Any exploration company will have dealings with all the staff.

Minerals BranchDETIColby HouseStranmillis CourtMalone LowerBELFASTBT9 5BF

Telephone: 028 9038 8462Fax: 028 9038 8461e-mail: [email protected]

The Role of DETIMinerals Branch is charged with administering all matters that fall under the 1969 Mineral Development Act. This includes processing prospecting licence applications and regulating all current licences. Minerals Branch is also responsible for the collection of statistics on mineral production in Northern Ireland and each year issues an Annual Minerals Statement detailing thequantity and value of materials extracted in Northern Ireland as wellas employment fi gures.

DETI is also responsible for Northern Ireland’s 2100 abandoned mine workings. A comprehensive programme of monitoring and proactive, predictive modelling is ongoing. The Department’s remit is to ensure that the location of all abandoned mines is recorded and that they are made safe to the general public.


Department of Enterprise, Trade and Investment

1. North Coast2. Coastal section, Co. Antrim3. The Mourne Mountains4. Owenkillew River5. The Giant’s Causeway

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Mineral exploration and mining in Northern Ireland is governed by the 1969 Mineral Development Act. This enables DETI to grant prospecting and mining licences for the development of Northern Ireland’s rich mineral heritage. The Act vested most minerals in DETI, with three main exceptions:

• Gold and silver remain vested in the Crown, therefore companies wishing to explore for them should apply simultaneously to the Crown Mineral Agent (CMA) and DETI. Two concurrent licences will be issued requiring the same work programme and expenditure to be completed.

• The mineral deposits which were being worked in 1969.

• Common substances including aggregate and sand and gravel.

Prospecting LicencesProspecting Licences are typically granted for an initial period of two years and can be renewed for two further periods of two years. Licensees must complete a scheme of prospecting (and associated expenditure) agreed in advance with DETI (and the CMA if applicable). Expenditure levels are negotiated at the commencement of the licence and DETI must be satisfi ed that the work has been completed before a renewal is granted. The licence expires at the end of the six-year period and further exploration requires the submission of an application for a new licence. In practice the associated scheme of prospecting is often a continuation of earlier work.

Licensees are required to submit annual work reports and expenditure accounts. The Mineral Development Act allows licensees to require that these be kept confi dential for up to ten years after their submission. The licence granted gives the licensee exclusive rights to prospect an area up to 250km2 including right of entry onto lands, however, the agreement of the landowner should be sought. In processing any application, DETI consults other stakeholders in the area and as a result the fi nal licence

document may include conditions to protect environmentally sensitive areas or to inform stakeholders of developments.

The application process normally takes about four months to complete once the applicant has provided all relevant information. DETI prospecting licences cost £450 plus any related advertising costs. Any company interested in exploring in Northern Ireland is encouraged to contact DETI and the GSNI as well as the CMA (if applicable) to discuss the licensing regimes, prospectivity of particular areas and data available.

Mining Licences and LeasesIf a company wishes to develop a deposit, it must apply for a mining licence or lease and provide to DETI all the necessary information to allow a proper assessment to be made. The company will also have to apply for planning permission from the Department of the Environment (DOE) through the Planning Service. Each application will be treated on its merits and on receipt of Planning Approval from the DOE, DETI will issue a mining licence or lease. A comprehensive consulatation period will be required before any licence is issued. The cost of DETI application is £2000. Under the 1969 Act compensation is payable to the ‘former mineral rights owners’ and DETI will collect an agreed royalty from the company based on the quantity of material mined to pay this compensation and cover its own costs. Any precious metals extracted will be the subject of royalties agreed with the CMA.

DETI GuidelinesIn 2003 DETI released a series of user-friendly guidelines designed to streamline the application process and standardise the reporting practices of companies operating in Northern Ireland. These guidelines take into account the changes in exploration and mining since 1969 and represent the fi rst step towards redrafting the Mineral Development Act.

Legislation

1. Fieldwork2. GSNI Fieldtrip3. Openday at GSNI 4. Garth Earls5. Mark Patton

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The Geological Survey of Northern Ireland (GSNI) was established in 1947 when the post-war government recognised the need for a detailed scientifi c assessment into the mineral potential of the country. Since this time the organisation has evolved to become the premier source for geological and geotechnical information in Northern Ireland and it offers expert advisory services to government, industry and the public as well as maintaining publically-available geological databases.

Although the GSNI is an offi ce of DETI, the GSNI scientifi c staff are employees of the British Geological Survey (BGS). This enables the GSNI to draw on additional BGS expertise. The GSNI also works in close cooperation with the Geological Survey of Ireland (GSI) and other organisations involved in earth science. In 2007 GSNI, GSI and BGS signed a co-operation document to progress geoscience in the British Isles.

Key PersonnelTwo GSNI staff members are directly responsible for the Minerals sector.

Garth EarlsGarth is the Director of the GSNI and is responsible for the overall management of the organisation as well as taking a proactive role in the Minerals Sector. Before joining the GSNI, Garth was a director of an international resource-based consultancy and prior to that was responsible for the discovery of the Curraghinalt gold deposit in Co. Tyrone.

Mark PattonMark joined the GSNI in 2004 as the Data Manager for the Tellus Project. He took the post of Minerals Geologist in 2007 where he is responsible for all minerals-related dealings with DETI and other government departments as well as managing the GSNI’s mineral exploration and Oracle database. Before joining the GSNI Mark worked for a software solutions company.

Geological DatabasesThe GSNI holds the following databases:

• 1:50,000 scale published maps and 1:10,000 scale fi eld sheets and associated memoirs.

• An open-fi le database of the reports of all companies who have worked in Northern Ireland.

• Boreholes database containing over 40,000 records.

• Technical mineral exploration reports completed by the GSNI.

• Quarries database and statistics.• Abandoned mines database and

ongoing monitoring.

Tellus Data• Regional geophysical survey

comprising 88,000 line kilometers of high resolution airborne geophysics (magnetics, electromagnetics and radiometrics)

• Regional geochemical survey comprising:

8087 regional soil sample locations; 5874 sediment sample sites; 5916 water sample sites.

Technical Reports SeriesThe GSNI has promoted mineral exploration in Northern Ireland through the publication of a number of technical reports highlighting the prospectivity of different areas.

Previous work includes:

• A gold metallogeny study of Northwest Northern Ireland.

Other projects underway includes:

• Fluid chemistry of gold mineralisation in Co. Armagh.

• The metallogenic evolution of the Tyrone Igneous Complex, Northern Ireland.

• Trace Element Abundance and Human Epidemiology.

Geological Survey ofNorthern Ireland

1. Soil sampling2. Digging a drainage ditch3. Au in soils4. Airborne survey aircraft5. Magnetic anomaly map

www.bgs.ac.uk/gsni

The Tellus Project, managed by the Geological Survey of Northern Ireland (GSNI), has generated new geochemical and airborne geophysical maps that extend and deepen our knowledge of the geology, soils, natural resources and environment of Northern Ireland. These are the most comprehensive and detailed geoscience survey results ever acquired in the United Kingdom on a regional level. The geochemical surveys map the distribution of 55 elements in three sample media and geophysical imagery provides improved detail on structures associated with gold and base metal mineralisation.

These data are a major resource for industry, regulatory authorities and researchers. The results have already prompted renewed interest in mineral prospecting in Northern Ireland, more than half of which is now covered by exploration permits or applications.

Digital datasets are now available of the following:

Geochemical data (each medium sampled at one site per 2km2)• Soil analyses at 20 and 50cm depths

- XRF and ICP with fi re-assay for gold and PGEs

• Stream sediment analyses by XRF and fi re-assay for gold and PGEs

• Stream waters analyses by ion chromatography and ICP.

Airborne data (line spacing 200m, ground clearance 56m)• Total magnetic fi eld and horizontal

gradient• Four frequency EM• Four channel radiometrics.

Geochemical samples have been collected from 13,000 rural sites. New anomalies in gold and platinum group elements have been mapped and the characteristics of gold mineralisation trends in the west, south and southeast are further defi ned. High nickel values characterise the Palaeogene volcanics and elevated nickel occurs elsewhere in several locations, notably associated with some of the Palaeogene dykes. The geochemical surveys extend the G-BASE

geochemical survey programme of the British Geological Survey.

Regionally, the airborne geophysical imagery refi nes existing structural mapping. Prominent magnetic anomalies correspond with major intrusive complexes and the extensive Palaeogene lava fl ows. The electromagnetic survey maps electrical conductivity differences between the Precambrian, Lower Palaeozoic and younger rocks. Radiometric results display signifi cant differences in the radioactivity of different lithologies, including some of the most radioactive granites in the United Kingdom. At a local scale the imagery reveals outstanding structural detail.

GSNI supplies data to academic and commercial users under a simple licensing scheme, at nominal cost. For full details about the data, formats, licensing arrangements, etc visit www.bgs.ac.uk/gsni/Tellus/index.html

The project has been fi nanced by the Department of Enterprise Trade and Investment (DETI) and by the EU’s ‘Building Sustainable Prosperity’ programme.


TELLUS PROJECT

geology · 1. 250k bedrock geology map 2. the sperrin mountains 3. geological map of the northwest...

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