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Angola

Instituto Geologico de Angola
P.O.Box 1260, Luanda
Phone: +244-2-323024
Fax: +244-2-321655/324989 
igeo@netangola.com

 Petroleum Activities Law


Source: CIA Factbook


Legend
Legend and ore deposit name

Geology
The geology of Angola comprises an extensive area of Proterozoic, dominantly (meta-)sedimentary,  sequences in the west of the country with enclaves of older Archaen crystalline basement, an area of similar basement rocks of Neoarchean age forms the Kasai Craton in the northeast of the country. The Proterozoic rocks include tillites, of the Bembe System, at the base followed by stromatolitic and oolitic limestones part of a thick sequence of overlying Mesozoic-Cenozoic marine sediments; clastic sediments and volcanic rocks of the Karoo Supergroup are found in a well-defined belt, the Cassanje Graben, in the north central region of the country. Magmatic activity of Karoo age included kimberlites and carbonatites located along a major trend line that transects Angola from NE-SW. The eastern region of the country is covered by continental sediments of the Kalahari Group.

Maps and images

  • CityView Corporation Ltd (ASX:CVI) confirmed in September, 2007, that mineralised copper zones exist within the Longonjo metals project in Angola.
    These assay results, drawn from selective channel sampling of all of the old exploration adits at the Catabola prospect, will be targeted during the current drilling program.
    CityView conducted channel sampling of 4 adits, representing approximately 230m of continuous sampling.
    The assay results were encouraging, with the best results coming from adit 2 which cross cuts the entire mineralised zone at Catabola.
    Sampling revealed an average of 84 m at 0.81 per cent copper in adit 2 within which exists a richer zone of 48.2 m at 1.21% copper with a peak of 4 m at 4.7% copper in one of the breccia zones.
    CityView is developing two projects in Angola, Longonjo and Ucua. The field program started at the end of April and will continue for seven months.
    The Longonjo licence covers an area of 3,764 square kilometres southwest of the city of Huambo in central Angola. The licence area lies within the Congo Craton, an Archaean basement which has been overlain by Proterozoic and Eocene sediments and intruded by a series of Proterozoic granites and Cretaceous ultramafic pipes.Work to date has revealed two prospects within the licence area. These have been named Longonjo Carbonatite and Catabola.
    Longonjo Carbonatite consists of an outer rim of altered granitoid around a series of central polymictic, carbonate rich breccias. The distribution of carbonatites in Angola is loosely related kimberlites and they are generally situated within the same NE-SW trend as the kimberlites. Longonjo carbonatite is known to be prospective for niobium, tantalum and uranium minerals in particular, as well as other minerals commonly associated with carbonatite complexes.
    Catabola is an IOCG (iron oxide copper-gold) occurrence situated in the southern part of the licence area. Copper and iron oxide mineralization has been identified over a 1.6km strike length, with copper minerals including azurite, malachite and chrysocolla constituting approximately 50% of the host rock.
    The Ucua licence covers an area of 1,358 square kilometres and hosts the Dande Pegmatite Complex. This complex is potentially an important source of beryllium, with studies conducted during the 1970’s indicating the potential for the occurrence of economic quantities of beryllium. 59 prospects have been identified in the Licence area and these will be examined in the current field season.

Diamond


West African Diamonds/Angola (Kevin Hulsey-Jewelry)

Diamonds were first discovered in Angola circa 1912, and from 1917 to 1975 the Portuguese parastatal, Diamang, had exclusive access to the mining of Angolan diamonds. After independence, Diamang became Empresa Nacional de Diamantes de Angola (Endiama)
Angola contains three types of diamond deposits, Quaternary (last 1,6 million years)  alluvial placers, Late Cretaceous (66 to 144 million years ago)  palaeoplacers and kimberlites. Alluvial  diamondiferous placers  were  first   discovered in  1912  in  the  Lunda Norte   Province   in   northeastern Angola,  following exploration upstream along  the  Luembe  River  from similar   deposits   in  the  Tshikapa   area  of  the  neighbouring  Democratic  Republic  of  Congo. Production started in 1916 and further discoveries of alluvial diamonds were made in the northward-flowing rivers   in the Lucapa-Saurimo region. Later, between  1950 and 1970, alluvial diamondiferous placers were found  in the Cuango River in the  western part  of  Lunda  Norte  Province,  and  the  Cuanza  and Catumbela   Rivers   of   central-western  Angola, but  of  these  only  the  Cuango  River  deposits have been worked. In the early  1950s, diamonds  were  discovered in  the  basal conglomerates (palaeoplacers) of the Calonda Formation in  Lunda  Norte   Province,   and  later  in  the  Kwango Formation of western Lunda Norte Province and eastern Malanje Province. These deposits have only been exploited on a small scale. The first kimberlite pipe, Camafuca-Camazamba, was found in 1952   in the   Chicapa   River, southwest of   Lucapa. It is the   largest   known kimberlite in the world, having a surface area of 1.6 km2. It was worked on a small scale, but is now dormant, though Southern   Era   Resources    had   signed    a   joint    venture agreement   to    renew    exploration. Many  other  kimberlites have been discovered since  then,  and although the  bulk  are concentrated in the  Lunda  Norte  Province,  they  are known to  extend southwestwards as far as the Namibian border. The total number of kimberlites discovered in Angola is 638, but   only 105 are diamondiferous. In 1998,   only   the   Catoca   pipe   north-northwest of Saurimo was being exploited.
It was reported in June 2013 that the Russian diamond company, Alrosa, believes that there are more than 1 500 kimberlites in Angola.


The Catoca kimberlite pipe and mine, is located 35 km NNE of the city of Saurimo in Lunda Norte Province, NE of Angola, close to the border with the Democratic Republic of Congo and has been the main hardrock producer of diamonds in Angola. 
Catoca Diamond Mine


Most of the Angolan diamond resources are concentrated in four kimberlite fields within the Archaean Kasai - Angola craton, namely the Camazambo, Catoca, Camutue and Camatchia fields which contain a total more than 70 kimberlite bodies distributed over a NNE trending interval of around 150 km and a width of up to 40 km, controlled by the NNE trending Lucapa regional fault zone. 

The Catoca pipe is a 900 m diameter, weakly eroded diatreme which covers a surface area of 65.7 ha. The intruded country rocks comprise Archaean granite-gneisses and crystalline schists. The pipe is overlain by Palaeogene to Neogene sands of the Kalahari Formation, ranging in thickness from the several to 130 m. 

The Catoca pipe includes crater, diatreme and hypabyssal facies kimberlite rocks. 

Crater facies volcaniclastic rocks comprise heterolithic breccias, psephitic and psammitic tuffs, alevrites and alevrolites with layered textures and variable amount of kimberlitic material. 

Diatreme facies are represented by eruptive kimberlite breccias with brecciated, partly autolithic, with massive groundmass textures. The structure of the rocks is porphyritic and clastoporphyritic. The groundmass is composed by serpentine-carbonate with minor amounts of altered phlogophite, rare perovskite crystals and opaque oxide minerals. 

The porphyritic kimberlite with massive textures and microporphyritic structures is described as a hypabyssal facies kimberlite. The porphyritic crystals are pseudomorphed olivine and phlogophite. The groundmass is composed by anhedral and euhedral olivine crystals, which are pseudomorphed to serpentine and a serpentine-carbonate mixture. Minor amounts of the phlogophite, spinel, ilmenite, perovskite and apatite are also present. 

The chemical composition of the kimberlitic rocks from the Catoca pipe show significant compositional variation between the different facies. 

The diamonds from the Catoca pipe are dominantly octahedral, although transitional and dodecahedral habits and flat faced octahedrons are also found. The primary kimberlite minerals are garnet, ilmenite, chrome-diopside and phlogophite. 

The Catoca pipe is the largest producer in Angola with an output of approximately 2.8 million carats in 2002. Total Angolan production for the same year was 5.02 million carats of diamond, much of the balance coming from the extensive alluvial diamond fields in the same province. 

The estimated reserve of the Catoca kimberlite in 2002 is reported to be 271 Mt @ 70 carats per hundred tonnes for 189.3 million carats of diamonds. 

The mine is operated by Sociedade Miniera de Catoca Ltda. (SMC), a joint venture between Empresa Diamantes de Angola - Endiama (32.8%), Russia's Almazy Rossii-Sakha Joint Stock Company - ALROSA (32.8%), Brazil's Odebrecht Mining Services Inc. (18.4%), and Israel's Lev Leviev (16%). 
  • SMC (Sociedade Miniera de Catoca), which is owned by Endiama (32.8%), Russia's Alrosa (32.8%), Brazil’s Odebrecht Mining (16.4%) and the Diamond Finance CY BV Group (18%) operates the Catoca Mine, the world’s 4th largest kimberlite. Reserves are estimated at 60 million carats. SMC intends increasing production to 5 million carats per year.
  • SouthernEra obtained government approval for the opening of Angola's second kimberlite mine, Camafuca, in 2002. The Camafuca Project is located in the Lunda Norte province of northwestern Angola, approximately 20 km southeast of the town of Lucapa. The project area covers the primary kimberlite deposits associated with the Camafuca-Camazamba kimberlite pipe, which is one of the world's largest known undeveloped diamond resources, with a surface area of 160 hectares. The Camafuca Kimberlite pipe is elongate, with its long axis oriented north-south. The pipe is 3,3 kilometres long and averages about 500 metres in width. Results of feasibility studies and exploration activities have shown that the various kimberlite facies of the Camafuca-Camazamba pipe, from surface to a depth of 145 m, contain an estimated total inferred mineral resource of some 209,5 million cubic metres at an average grade of 0,111 carats per cubic metre (cts/m3). This is equivalent to an estimated in-situ diamond content of 23 million carats.
  • Development of Angola's third kimberlite mine Camatchia -Camagio was granted to a joint venture with similar shareholders as Sociedade Miniera de Catoca.
  • Petra Diamonds, in a joint venture with BHP Billiton, is exploring the Alto Cuilo kimberlites in the northeast of the country. Petra Diamonds Ltd and its Angolan partners, Endiama and Organizacoes Moyoweno, began drilling the diamondiferous kimberlites in 2004.
  • BHP Billiton is involved in a second joint venture with a Portuguese bank, Escom; the partners hold three concessions covering 12000km². They are at an earlier stage of exploration.
  • Xceldiam Diamond Exploration & Mining's interest in the Luangue Concession are held through the Projecto Luangue Joint Venture in which Xceldiam holds a 40% interest in the alluvial and a 39% interest in the kimberlite licenses. The other participants in the Projecto Luangue JV are the Angolan state's diamond company, Endiama, and a consortium of Angolan nationals, Bapsil Service Lda. In May 2006, Xceldiam entered into a strategic cooperation agreement with Petra Diamonds. In terms of this agreement information is shared and technical, operational and other related activities are co-operated on in the development of Xceldiam’s Project Luangue and Petra’s neighbouring Project Alto Cuilo (where the latter is in JV with BHP Billiton). Petra Diamonds will buy Xceldiam’s Angolan assets in an all-share transaction valued at £32 million, and it has raised a loan of $20m through its partner BHP Billiton to develop Angolan diamond projects, Petra CEO Johan Dippenaar said on March 1, 2007.
  • Trans Hex Group has been involved in the mining of the Fucauma (32% share) and Laurica (35% share) alluvial deposits since 2003 and has signed a contract with state diamond miner, Endiama, on the Luana deposit (33% share). The company has also continued kimberlite exploration on its Gango concession where potential for a moderate to low diamond bearing kimberlite has been identified.
  • Sociedade de Desenvolvimento Mineiro de Angola, S.A.R.L. (SDM) is a joint venture between Endiama (50%) and Odebrecht (50%) exploiting the Tazua alluvial deposit at its Luzamba project.
  • Sociedade Mineira do Lucapa (SML), representing Endiama (51%) and Sociedada Portugese de Empreendimnetos (49%), along with operators ITM Mining, operate several alluvial concessions in the Lundes, viz the Calonda project that produced 199 000 ct, the Mufuto project that yielded 244 000 ct and the Lucapa project 69 000 ct in 2001. SML also holds a 15% interest in Southern Era’s Camafuca project.
  • Associacao Chitotolo, owned by Sociedada Miniera de Lumanhe (15%), ITM Mining (50%) and Endiama (35%) mines alluvial deposits and produced 232 000 ct in 2001.
  • De Beers involvement in Angola: De Beers first undertook grassroots prospecting in Angola from 1970 to 1975 as the company Condiama, a joint venture with Diamang, the Portuguese parastatal. Operations terminated with the outbreak of civil war in mid-1975. Diamang became Endiama, and De Beers later returned as MATS (Mining and Technical Services) in a joint venture with Endiama, operating from 1979 to 1984 mining the alluvial deposits in the Lunda provinces. Following the conclusion of negotiations with the Angolan Government in 1996, prospecting agreements were entered into for three concession areas being Lunda northeast, Quela (central) and Mavinga in the southeast. From 1996 to 2001 De Beers embarked on an ambitious prospecting programme in partnership with Endiama, to discover and evaluate kimberlites. Due to poor security conditions on the ground at the time, no work was possible in the Quela and Mavinga concessions, but in the Lunda concession some 60 kimberlites were discovered. Most are located under deep sand cover and require further investigation and detailed sampling before some idea of their economic potential is understood. Over this period De Beers spent over U$32 million on the prospecting programme alone. Operations were suspended in May 2001 pending negotiations with the Angolan Government and Endiama on the terms applicable to mining and marketing of diamonds from mines discovered from De Beers prospecting. Following a period of four years in which De Beers could not operate in Angola, in its session of the 27th May 2005, the Angolan Council of Ministers approved the Joint Venture Contract between Endiama and De Beers Angola Prospecting Limited – DEBAP, to exercise the mineral rights for prospecting, evaluation and research of kimberlite deposits in the Lunda North Concession area. The Contract was signed on the 17th of June 2005, and the Joint Venture Company is known as ENDEB. Prospecting operations were scheduled to commence in the third quarter of 2005.
  • Gem Diamonds signed a Cooperation Agreement and an option to acquire an interest in the Chiri kimberlite concession in the Lunda Norte province of Angola. A feasibility study will be conducted over Chiri, whereafter Gem Diamonds will have an opportunity to acquire up to 20% of Chiri, a known diamondiferous kimberlite cluster. Chiri is located approximately 5 km from Catoca, one of the world's largest diamond mines and amongst a cluster of other known kimberlites. The Cooperation Agreement concluded with Avantis Angola Inc also provides for a joint venture relationship for the future exploration and exploitation of other Angolan diamond assets.
  • Pangea Diamond Fields plc (Also active in Congo -Kinshasa, Central African Republic and South Africa) has been pilot mining the Cassanguidi alluvial project, Lunda Norte Province, north eastern Angola. Diamondiferous gravels are extracred from river terraces and hill-wash deposits using conventional open pit methods and river bed gravels, by pumping from a raft. A total of 25,416 cts was produced by pilot mining from Cassanguidi during the period February 2005 to March 2006. Stone sizes for the open pit operation have varied between 0.23 ct/stone and 0.42 ct/stone, with an average of 0.35 ct/stone. Continuing mining operations were hampered in the fourth quarter of 2006 due to the excessive seasonal rains, resulting in diamond production being significantly less than expected; 5,690 carats were produced during the quarter. Average diamond revenue from sales to Sodiam, Endiama’s marketing arm, have been disappointing and, in the Company’s opinion, well below market value. Plans to develop the project further will be deferred until there is a mechanism in place to ensure sales at market-related levels can be achieved and are sustainable. Discussions regarding the sale and marketing procedures are ongoing.
  • Nare Diamonds Ltd (Lonrho Mining Ltd) has signed a joint venture agreement with state-owned Endiama to develop the 3,000 sq km Lulo diamond concession in Angola. The Lulo concession is located in the Cuango River catchment area within the Lunda Norte Province of northeastern Angola.
  • International Gold Exploration AB has been granted a concession right in the Luanda Norte province, one of Angola's richest diamond regions, and one in the Kwanza Sul province. The Kwanza Sul province hosts the third most important diamond primary source in Angola. Luxinge and Nhefo in Lunda Norte and Cariango in Kwanza Sul are both primary and secondary diamond exploration projects.
    Based on the results from the bulk-sampling program underway, the concessions are expected to produce 120,000 carats per year once IGE enters into its 5-year full production program in 2009. The Angolan government authorised the concession of rights of diamond prospecting of the Lacage kimberlite, Luacheze district, eastern Moxico province, to the National Diamond Company of Angola (ENDIAMA), in an area of 3,000 square kilometres. In the same document the government authorised and approved the setting up of the Association in Participation in Lacage, between ENDIAMA, International Gold Exploration (IGE), the "Sociedade Mineira do Leste" (Somileste) and Magma - Commerce, Industry and Supply of Services.
    Participation quotas of the referred contract are 51 percent for ENDIAMA, 43 for IGE, four for Somileste and two for Magma.
  • Signet Mining Services Ltd secured a concession to mine diamonds in Angola. The pipe Chirri is situated near the town of Saurimo and approximately 5km from the Catoca kimberlite mine.
    Catoca and Matikara have conducted historical work at the site, including bulk sampling and delineation drilling. Although the drilling programme was small, the pipe was confirmed to be to be over 600m in width and estimated to be as large as 50 ha.

Gold in Angola

Gold Home

Gold deposits in Angola (Source: Southern African Development Community, Mineral Resources Survey Programme No 4, 2001) 

No industrial gold mining operations exist in Angola. Approximately 90% of the country's production has been mined by artisanal miners. Both Huila and Cunene Provinces have been prospected by companies such as Ashanti Gold Company Limited and Anglo American plc in the past.
  • Maiombe
This  area  is  situated  in  the  north  of  Angola  in  the Cabinda province, which is separated from the rest of the country. With over 500 kg gold reported to have been removed here, the Maiombe area accounts for approxi­ mately 90 per cent of all gold produced in Angola. The principal deposits worked were small tributaries of the Luali River in central Cabinda. The alluvial-gold con­centrates were usually associated with vein-quartz  gran­ ite and altered basic volcanic rock. Most of the produc­tion took place between 1938 and 1945. The thickness of the auriferous gravels varied from 0,2-1,2 m, the width of the river bed from 10-50 m. The average recovered grade was between 1 and 2 g/m3 Au, but there were a number of higher-grade  'pockets'. By 1950 the produc­tion had virtually  ceased,  mainly  owing  to removal  of high-grade material leaving only lower grades (now less than 1 g/m3  Au). Other alluvial gold deposits are found in Kwanza Norte, Huila and Cunene provinces.
  • M'popo Cassinga Deposit
The presence of auriferous alluvial gravels in the Colui River, and its tributaries, and gold-bearing  quartz veins has been known in this area since 1889. Prospecting and artisanal mining were carried out intermittently  by vari­ ous companies until the M'Popo auriferous quartz veins were discovered by the Companhia Mineira do Lobito in the mid-1960s. M'Popo, located about 36 km southwest of Cassinga, is the largest known primary gold deposit in Angola, with an estimated possible reserve of 700 000 t at 8 g/t Au (Ministry of Geology and Mines, 1998). It is estimated that 23 300 t of ore at 6 g/t Au (a total of 140 kg gold) have been mined.  Alluvial placer deposits also occur nearby, and have been mined in the past.

The Angolan Company of Precious Metals (Somepa) is developing gold prospecting activity, in an area of 80 square kilometres at M'popo, Tchamutete commune, an extension already studied by Portuguese from 1975 to 1976, said, the general director of that company, Djanira dos Santos on 10 June 2012.
In an interview to Angop, during the visit of secretary of State of Geology and Mining, Mankenda Ambroise, the official said that it is a zone chosen between an area of 3,384 square kilometres of concession, where the mining location was already defined.
According to the director, study to ascertain the contents, the existing reserves and the amount of ore to explore, later to make the economic feasibility study and determine the type of operation (underground or open pit), the plant beneficiation as well as the environmental impact study is being done.

Geology and gold mineralisation:

The gold occurs within an andesitic metavolcanosedi­ mentary sequence of the Palaeoproterozoic  Chivanda Group, intruded by a granite batholith.  

The ore is hosted in a 1 to 3 m wide quartz-vein  system, some 600 m in length. Gold occurs as either free gold associated with sulphides and tellurides, or as finely disseminated  gold  inclusions  in  pyrite,  galena  or  sphalerite. Near surface, most of the ore is free gold within quartz veins and there has been supergene enrichment within the oxidised zone. Two basic types of veins can be distinguished:

1.  Relatively  short, discontinuous,  quartz  veins occur­ ring parallel to and/or cutting the regional foliation, often with visible gold particles. This kind of ore generally yields the highest gold content;


2.   Quartz veins which are brecciated and silicified and injected by later quartz veinlets. This type of ore con­ stitutes the major volume of the total reserve of the area. The gold is very fine grained and grades range from 0,7-10 g/t Au.


With depth, the gold is increasingly associated with sul­ phides,  mainly  pyrite  and chalcopyrite, but  also pyrrhotite,  bornite and chalcocite.  Ore grades diminish with depth. Hydrothermal  alteration  in the host rocks is represented mainly by carbonatisation  and sericitisation.


Alluvial  placer  deposits  are also  common  in the area, and were mined by prospectors  in the past. There have been reports of gold within the widespread  banded iron formations in the vicinity of the known gold veins.

  • Chipindo deposit
Gold was found in this region in 1965 by conducting fol­low-up work on geochemical anomalies. Subsequently quartz veins with grades ranging from 4-20  g/t Au were mined from a block measuring  50 m3 . From  1973 two concessional  areas were surrendered to a private compa­ny named Cromalloy Angola SARL. Over 200 excava­tions were dug along riverbeds and several tributary val­leys. Subsequently, Cromalloy constructed a gravitation­al plant with a treatment capacity of about 100-250 t of gravel per day. The amount of gold recovered to date is unknown.  Despite  numerous  prospecting  and  develop­ment  works  carried  out  over  a  number  of  years,  ore reserves were never calculated.

Geology and gold mineralisation
In the Chipindo area, auriferous quartz veins occur in Precambrian   metasediments   (mainly  shale  and  sand­ stone) of the Bale Group which have been intruded by granites.

The  shear-hosted   gold-bearing   quartz  veins  occur  as steeply  dipping  lenticular bodies  rich in pyrite, arsenopyrite, chalcopyrite and pyrrhotite, with small amounts of galena and silver. Free gold is very rare. On weathering,  the sulphides  oxidise  to produce  a promi­ nent brown, ferruginous stain. The quartz veins can be either concordant or disconcordant and are foliated. In places, dolomitisation has occurred as a result of the hydrothermal  activity.

It is thought that much of the potential of these deeply weathered  deposits   has   been   removed   by   erosion (Ministry of Geology and Mines, 1998). It is therefore only the roots of the veins that are now left and all that remains of the upper auriferous portions is to be found in the alluvial deposits derived therefrom. (Alluvial gold has also been found in a number of streams and in some of the older terraces).
  • Gandavira-Samboto
This area in the Huambo Province is known mainly for its placer-gold occurrences in the Samboto and Chiviri streams, both being tributaries of the Cunene River. However, vein quartz with visible free gold has been located within the gravels. It has been reported that the numerous quartz veins occurring in the area are the source of the auriferous gravels in the streams. Mineralogically, the gold is associated with magnetite, monazite, zircon and cassiterite. Gold was exploited in 1945 and 1947, with recorded productions of 1 kg and 3  kg  of  gold respectively (Ministry of Geology and Mines, 1998). Resources are unknown.
  • Kwengwe-Kwanjanje
About 15 km northeast of Chipindo, gold-quartz veins of the Kwengwe Kwanjanje deposit occur within Precam­ brian granite. The gold content has been reported to be up to 46-87 g/t. The open pit at Kwengwe was operated by the Sociedade Mineira de Huila from 1962 to 1969. In 1974 Chromalloy Angola, a subsidiary of Chromalloy American Corporation, was supposed to resume opera­tions. Further details are unknown.
  • Lombige
Gold has been recovered at times by artisanal miners and prospecters from the Lombige River and its tribu­ taries in the Cuanza Norte Province since 1754. Grades of 3-4  g/m3   Au have been reported for certain areas. Ancient rumours concerning rich gold occurrences could not be verified by companies prospecting the area in the 1940s and 1950s. The source areas of the alluvial gold have been described as consisting of granite, gneiss and basic rocks of Archaean and/or Proterozoic age.
  • Menongue-Cuchi
At the Menongue-Cuchi deposit in the Huila Province, mineralisation is hosted by 1 to 3-m-wide, and up to 300m long, fractures filled with vein quartz. Ore mineralogy consists of malachite, azurite and chalcocite with associ­ated gold and silver. Host rocks are greenstones and intrusive granite. The average grades obtained from five samples were 3,6 g/t Au and 8,6 g/t Ag (Ministry of Geology and Mines, 1998).
  • Bundjei
Beds with thin auriferous layers (0,5 m) were detected in the Bundjei River in the Huila Province. Gold distribu­ tion is very irregular. Average ore grade is 0,5 g/m 3• Gold occurs associated with haematite, ilmenite, garnet, rutile and monazite.
  • Canjanja
At Canjanja in the Huambo province gold-quartz veins occur in Precambrian metasediments of the Bale Group. Auriferous gravels with reported grades of 1-4 g/m3  Au have also been found in a number of streams and in some older terraces.
  • Capangombe
Gold-copper mineralisation was reported at the Capangombe Mine in the Mocamedes District in the Rio Bibala area. No other information is available.

Exploration trends

Lubango
Ownership in 2001:   Easton Minerals Ltd 100 per cent In February 1997, Easton Minerals had its 20 050 km2 Lubango prospecting licence in the Huila district approved. Gold is hosted within an igneous complex similar to South Africa's Bushveld Complex and this complex extends into Namibia. The area hosts metalli­ferous deposits including gold, nickel, cobalt, copper, vanadium, chromium and platinum. Exploration was continuing in 1998.

Conclusion

Numerous anomalous gold grades have been found in soil samples within a 5-km radius of M'Popo, but only some of them have been evaluated in more detail. The M'Popo Cassinga area therefore appears to have excel­lent potential for additional ore. Also, exploration for alluvial gold in the Chipindo area is highly recommend­ed (Ministry of Geology and Mines, 1998). The distri­bution and expected volume of the remaining gold in the Maiombe area are probably insufficient for mechanised mining methods. However, the area may still have some potential  for  artisanal  mining.  An  exploration  pro­gramme searching for the primary source of the alluvial gold at Maiombe is recommended. It appears that the Lombige area does not represent a prime target for allu­vial mining, either mechanical or artisanal, but further sampling is suggested to substantiate the results. With an average gold content of0,5  g/m3,  the gold occurrence at Bundjei is non-profitable owing to the small thickness of productive layers. In the Menongue-Cuchi area, copper mineralisation appears to be uneconomic, but the poten­tial for gold mineralisation has not been fully evaluated and  further  sampling  is  warranted.  The  Kwengwe­ Kwanjanje deposit is also worth investigating in the light of the high ore grade reported.


Iron Ore
Once one of the country's major exports, iron ore was no longer mined in the late 1980s because of security and transportation problems. From the mid-1950s until 1975, iron ore was mined in Malanje, Bié, Huambo, and Huíla provinces, and production reached an average of 5.7 million tons per year between 1970 and 1974. Most of the iron ore was shipped to Japan, West Germany, and Britain and earned almost US$50 million a year in export revenue. After independence, the government established a state company, the National Iron Ore Company of Angola (Emprêsa Nacional de Ferro de Angola--Ferrangol), for the exploration, mining, processing, and marketing of iron ore. Ferrangol contracted with Austromineral, an Austrian company, to repair facilities and organize production in Cassinga. Production began to slow in 1974 as a result of technical problems at the Cassinga mine in Huíla Province and stopped completely in August 1975. The area fell under foreign control after South African forces invaded in 1975. Although South Africa withdrew its troops in early 1976, as of 1988 mining had not resumed in the area.

By 1988 the Cassinga mines had a production capacity of approximately 1.1 million tons per year. However, the railroad to the port of Namibe (formerly Moçâmedes) needed extensive repair, and since it was located only 310 kilometers north of the Namibian border, security against South African attacks could not be ensured. Furthermore, UNITA was active in the area and posed a threat to the rail line if it were repaired.
 The Cassinga iron deposit is located on the southern margin of the Angola-Kasai Shield, on the southern part of the Archaean Congo (Zaire) craton.   It is 630 km by rail east of the Atlantic Ocean port of Namibe (Mocamedes) in southern Angola. 


The Angola-Kasai Shield comprises a core of Archaean overlain by Paleo- to Neoproterozoic successions, intruded by Proterozoic granitoids and covered over large areas by mainly Mesozic to Cenozoic cratonic sediments. The succession is as follows, from the base: 

i). Mesoarchaean - 3.4 Ga Upper Luanyi gneisses and migmatites, separated by an inferred fault from and the adjacent Kanda Kanda grey tonalites and granodioritic gneisses and alaskite gneisses;

ii). Kasai-Lomami gabbro-norite and the dark, acid, enderbitic-charnockitic assemblage, all of which have been metamorphosed to granulite facies, with a date of 2.8 Ga;

iii). Neoarchaean Dibaya granitic to tonalitic migmatite assemblage and calc-alkaline granites with metamorphic ages of between 2.82 and 2.56 Ga;

iv). Paleoproterozoic Luiza Supergroup - a meta-sedimentary sequence of quartzites, mica schists and iron formations unconformably overlying the Kanda-Kanda gneisses. Both the Luiza Supergroup and Archaean basement were deformed and metamorphosed by the earliest Eburnean event at 2.42 Ga.

iv). Possible Lukoshi metasediments, which with the Archaean basement were deformed and metamorphosed by later Eburnean events between 2.2 and 1.9 Ga and intruded by a post tectonic (2037 ±30 Ma) granodiorite.

v). Lulua Group - a meta-sedimentary and meta-volcanic suite up to 6000 m thick to the north of the Luiza Supergroup as a 170 x 20 km belt, composed predominantly of slates and quartzites which are intercalated with greenstones (1469 ±30 Ma spilitic, pillowed basalt lavas) and intruded by post tectonic 1468 ±30 Ma syenodiorite sills.

vi). Damara-Kaokoveld orogen sediments to the south. 

The Cassinga deposits are developed within the iron formations of the early Paleoproterozoic Luiza Supergroup: 

Three styles of ore and mineralisation are recognised: 

i). Primary banded hematite iron formation containing 40% Fe. Resources of this ore type have not been mined (2000) and amount to approximately 1 Gt. 

ii). Supergene enriched ore hematite ore with 62% Fe, 6% SiO2, 0.1% P. The reserves in 1970 were estimated to have been 11 Mt. 

iii). Detrital (canga) ore in 15 different areas around the main deposit, with a grade of around 61% Fe, 0.04% P. The reserves in 1970 were estimated to have been 150 Mt. 

Past production comprised 40 Mt of enriched in situ ore @ 50 to 60% Fe between 1957 and 1975, 6.1 Mt of which was mined in 1974. Proved and probable reserves are estimated at 34.2 Mt @ 44% Fe. (Source:  http://www.portergeo.com.au/database/index.asp)


Oil and Natural Gas
Proven reserves

Oil: 10 470mmbbls

Gas: 12.93Tcf
   
The National oil company is Sociedade Nacional de Combustiveis de Angola (Sonangol)
The Key players are
BP
ExxonMobil
Repsol
Chevron
Falcon Oil
Somoil
China Sonangol International
Galp Energia
Sonangol
Cobalt International Energy
Maersk
Sonangol Sinopec International (SSI)
Cubapetroleo
Marathon
Statoil
Eni
Petrobras
Total
Highlights in 2014
• As of 2013, Angola’s daily production was 1.6mmbbl/d.
• Angola was the first country in Africa to license deepwater oil exploration.
• Oil production has increased by 400% over the last 20 years.
• Gas use and flaring has become an increasingly important issue for the  country, and the Government is offering incentives to companies to explore and exploit gas commercially.
• By 2020, Angola plans to produce 3.5mmbbl/d.
Recent developments
• Angola became an LNG exporter in 2013 with the commissioning of the  Angola LNG plant in Soyo. The plant has a capacity of 5.2 million tonnes per year.
•Total has started up production on the offshore CLOV field, increasing Block 17 production to 700 000bbl/d.
• Statoil has farmed out a 5% interest in a deepwater Angola block to Sonangol for USD200 million.
• In May 2014, Cobalt International tested and confirmed substantial reserves in its Orca-1 pre-salt block well, its fifth consecutive deepwater discovery in Angola’s Kwanza Basin which it discovered in February 2014.
• Local content concessions are believed to have facilitated Total’s Kaombo final investment decision (FID)
• In mid-2014, Sonangol launched a bidding round for 10 onshore blocks in the Kwanza and Congo basins.
• The 200 000bbl/d Sonaref refinery project at Lobito is expected to come  online by 2016. Since local demand for refined products is relatively low, this will likely add to Angola’s export capacity, which primarily goes to the US and China.
• Entry into Angola by new companies has become difficult as the Government seems to prefer major companies with superior finances and technical ability
China reportedly accounts for 35% of oil exports from Angola.



According to Oil and Gas Journal (OGJ), Angola had proven oil reserves of 8.0 billion barrels as of January 2007. The majority of the reserves are located in Angola’s offshore blocks. Blocks 15 and Zero have been the most prolific offshore blocks. Proven reserves are also located onshore near the city of Soyo.
Angola’s crude oil production has more than quadrupled over the past two decades. In 1986, crude oil production averaged 280,000 barrels per day (bbl/d), while production in 2006 averaged 1.4 million bbl/d. According to EIA estimates, Angolan oil production is set to reach two million bbl/d by 2008, when new deep-water production sites are expected to come online. Also consistent with EIA estimates, in December 2006, the World Bank announced that Angola will likely see peak oil production in 2011 at 2.6 million bbl/d followed by production declines if there are no new oil discoveries.
Angola exports crude oil primarily to China (477,000 bbl/d as of November 2006) and the United States. In 2005, the United States imported approximately 473,000 bbl/d of oil from Angola, which made Angola the eighth largest supplier of crude oil to the United States. As of October 2006, the United States had imported an average of 526,000 bbl/d of oil from Angola. Angola also exports crude oil to Europe and Latin America.
In 1976, the Angolan government created a national oil company called the Sociedade Nacional de Combustiveis de Angola (Sonangol). In 1978, Sonangol became the sole concessionaire for oil exploration and production in Angola. Sonangol works with foreign companies through joint ventures and production sharing agreements (PSAs), while funding its share of production through oil-backed borrowing. Major international oil companies operating in Angola include BP, Chevron, Devon Energy, ExxonMobil, Maersk, Occidental Petroleum Corporation , Roc Oil and Total.
  • Oil production: 1.6 million bbl/day (2005 est.)
  • Oil proved reserves: 25 billion bbl (2006 est.)
  • Natural gas production: 750 million cu m (2004 est.)
  • Natural gas proved reserves: 45.87 billion cu m (1 January 2005 est.)
  • Cabinda Gulf Oil Company (CABGOC), a Chevron subsidiary and has been the operator of Block Zero since 1955. In May 2004, Sonangol and the Angolan government extended CABGOC’s contract, which was set to expire in 2010, to 2030. Other partners on Block Zero include Sonangol, Total and Eni. Block Zero is located offshore Cabinda province and accounts for approximately 370,000 bbl/d of Angola’s oil production, or almost one-third of Angola’s total crude oil production. In addition to Block Zero, CABGOC is the operator of deepwater Block 14. A total of nine discoveries have been made on the block with Kuito being the first in 1997. Two years later, Kuito became Angola’s first producing deepwater field. Chevron's combined average net production in Angola and Nigeria was 264,000 barrels of oil equivalent per day in 2005.
  • ExxonMobil's Kizomba B project in deepwater offshore Angola Block 15 commenced production in July 2005. Block 15 has estimated recoverable hydrocarbon reserves of 4.5 billion barrels, and at peak production, Block 15 is expected to produce 750,000 bbl/d.
    The current production rate is more than 250 thousand barrels of oil per day.
  • Total's Girassol field was discovered in April 1996 by Elf Exploration Angola. Just over 2 years later, on 8 July 1998, the company obtained the official go-ahead from Angola’s national oil company Sonangol and the Girassol partners to launch a development project. Girassol, which was the first field on Block 17 to go into production. It has the capacity to produce 200,000 barrels per day. Total operates Block 17 with a 40 percent share, while Sonangol is its franchise holder. Other shareholders include ExxonMobil, BP, Statoil, and Norsk Hydro. Total has six discoveries on Block 32, which is located in ultra-deep water, 40 miles from Block 17’s Girassol find. Currently, the discoveries are being analyzed for a potential joint venture project. Total, as operator of the block, is joined with partners Marathon Oil Company, Sonangol, ExxonMobil and Petrogal.
  • Petrobras began operating in the country almost thirty years ago, in 1979, and has exploration and production agreements via participation in six offshore Blocks, one in production (Block 2) while the other 5 being explored.
  • In February 2003, Devon Energy Corporation acquired a 25 percent stake in Block 24 from ExxonMobil. This acquisition increased Devon Energy’s total share of the block to 40 percent, making the company the operator of the block. ExxonMobil retains a 20 percent share. Sonangol and Petronas are also partners on the block. Devon Energy Corporation owns interests in three Angolan offshore exploratory blocks (blocks 10, 16 and 24) and one onshore block.
  • In February 2004, Sonangol approved BP’s plans to develop the Greater Plutonio project in Block 18. Six fields (Colbalto, Cromio, Galio, Paladio, Platina, and Plutonio) will be developed using a single FPSO. Scheduled to come online in mid-2007, the Greater Plutonio project is expected to produce 240,000 bbl/d. BP maintains a 50 percent interest as the operator of Block 18 and Sinopec owns the other 50 percent share. In October 2006, BP announced its 11th discovery on Block 31. Industry experts believe Block 31 to contain 500 million barrels of commercial reserves. The block is located 118 miles offshore. BP is operator with 26.67 percent interest and is joined with partners ExxonMobil, Sonangol, Statoil, Marathon, and Total.
  • In December 2006, Sonangol awarded French-based Technip a $70 million contract to develop the Gimboa field in Block 4.
  • Tullow Oil plc concluded a farm-in agreement with Sonangol P&P in November, 2005, acquiring a 15% interest in Block 10/05 offshore Angola. Block 10/05, located in the Southern Kwanza Basin, is operated by Devon Energy. In early January 2006 Tullow completed a further farm-in agreement with Ocean Angola Corporation, a subsidiary of Devon Energy, acquiring a 15% interest in Block 24/99. In late July 2006 Tullow was formally advised that it had been awarded a 50% operating interest in Block 1/06, a 3,839 sq km oil exploration concession in the Lower Congo Basin, offshore Angola. The Production Sharing Contract came into force in December 2006. Block 1/06, which extends from a water depth of 40m to approximately 300m, contains three undeveloped oil fields, Pitangueira, Bananeira and Sapesapeiro.
  • On November 2, 2006, VAALCO Energy, Inc officially signed a Production Sharing Agreement (PSA) for Block 5 offshore Angola.
    VAALCO has a 40% interest in the block, and is the operator of the concession for its partners Interoil Exploration & Production ASA (40%) and Sonangol (20%). Block 5 covers an offshore area of approximately 1.4 million acres.
  • In addition to licensing rounds, Angola signed various bilateral oil agreements in 2006 with Russia, Sao Tome and Principe, South Korea and Venezuela. The agreements promote increased collaboration on future oil exploration activities in Angola.


Australia’s Minbos Resources (ASX:MNB) has been exploring for phosphate in Angola at its property in Cabinda province, an area situated in the middle of the DR Congo and Congo Brazzaville; in fact, the phosphate formation is the same that is being developed by Elemental Minerals and Toronto based MagIndustries. Minbos noted that the phosphate mineralization is often found with underlying areas of potash, suggesting that the property has the potential to produce both minerals. 

On May 15, 2012, Minbos announced the results of its recent drilling campaign, which the Company says, confirm the existence of phosphate mineralization very close to the surface. The assays have shown the existence of P2O5 ranging from 31.4% to 28.24% at depths of 11 meters to 16 meters respectively. The deposits also have direct shipping  potential at the Cacata and Chivovo deposits. The company has indicated that, while it is destined to increase, the project has a JORC resource of 254.1 million tons of 12.6% phosphate. A scoping study is currently underway, which should boost those figures. At the Cacata deposit, Minbos will upgrade part of the 33.9 million ton resource (15.75% P2O5) from Indicated to Measured. 

Minbos says that the results from the ongoing scoping study and the upgraded resource estimates will form the basis of the Feasibility Study as it aims to become a low capex phosphate rock producer. Minbos’s resources are located about 50km from the Atlantic Ocean in an area that is well supplied with transportation infrastructure, including roads and ports, given the presence of several oil companies. Angola’s geographic position also makes Minbos phosphate an idea candidate for shipment to Brazil and other South American countries, where there is strong demand for phosphate. As noted above, the presence of potash mineralization also serves as a launch-pad for Minbos’s entry in the potash market. 


Economic geology of energy sources


Economic geology of nonmetal deposits

Economic geology of ore deposits

Economic geology, general

Economic geology, general, economics


Posted by Carel van der Merwe at 12.4.07