At the Codli mines, the lower grade iron formation is folded and subsequently eroded into basinal areas amenable to open-pit mining. Economically mineable material occurs over an area of about 3.1 km by 1.6 km and is located between 84 metres above sea level and 50 metres below sea level. The formations show a general northwest-southeast trend with shallow to moderate dips towards the northeast with local reversals. The footwall is comprised manganiferous clay and decomposed quartzites and the stratigraphy of the ore body is cross cut by late dolerite dykes and sills which are manifested by pink clayey zones in the mine area.

The area surrounding the Sonshi mine is covered with laterite capping underlain by lumpy ore zone. The ore deposit at the Sonshi mine forms the northern limb of the northwest-southeast trending syncline. The formations dip 50 degrees to 60 degrees northeast. The principal deposit of the Sonshi mine comprises three distinct ore bodies that are folded into a syncline. The youngest ore body has a width of 50 metres, while the other ore bodies dip steeply to the northeast and have widths of approximately 20 metres to 25 metres. The intervening parting between the ore bodies comprised 50 metres of manganiferous clay and a 30 metre wide limonitic zone separating one ore body from the footwall phyllite. The depth extent of these bands has been outlined with deep drilling. Hematite is the major economic mineral in each of the bands.

Bicholim-Sirigao deposit is the best deposit of Goa state. It is situated between Bicholim in the south-east and Sirigao in the north-west. The deposit occurs oa a N 50-60o W trending anticlinal fold, overturned to the south-west and its nose portion refolded in shape of 'S' with a plunge of about 22-27o towards N 60o W. The southern limb of the fold extends for a length of about 4km from Bicholim-Piligao road in the south-east to about 500m north-east of Sirigao hill while the northern limb extends for a length of about 2km from Bordem in the south-east to about 500m north-east of Sirigao hill. Between the two limbs of the anticlinal fold, which are ore-bearing, there is a barren phyllitic tract which represents the axial portion of the fold.

The deposit consists of two orebodies, a larger south-western one and a smaller north-eastern. The total length of the south-western body between Bicholim-Piligao to Sirigao hill is about 6.25km and the windth varies from 70m to 550m. The north-eastern orebody is about 1.25km in length and the windth varies from 115m to 140m. Both these orebodies are thoroughly explored by drilling and proved up hte bottom.

As regards the quality of ore, the best grade of ore in south-eastern orebody is present in the section between Lamgao and Sirigao hill. Here, the Fe content lumpy ore ranges from 60 to 63 percent and in powdery ore from 64 to 66 percent. In Seltom Mosque hill area, the lumpy ore contains 57 to 59 percent Fe and the powdery ore from 61 to 63 percent Fe. In sectin between Bicholim-Maem road and Lamgaon the lumpy ore contains 57 to 61 percent and the powdery ore from 63 to 65 percent Fe. Along the northern and north-western slope of Sirigao, the lumpy ore contains 57 to 59 percent and the powdery ore from 61 to 62 percent Fe.

In the north-western orebody, the lumpy ore is platy to massive and contains 59 to 61 percent Fe and the powdery ore which is deep blue in colour, contains 62 to 65 percent Fe.

Cudnem-Dignem-Surla deposit: The deposit extends from a point 2.25 km south-west of Onda and west of the Onda Usgno road in the north-west of Surla hill, located about 1 km east of Dergunvado in the south-east. The deposit has a length of about 3.5 km and a width ranging from 100 m in the south-eastern portion to about 60 m in central portion and about 220 m in the north-western portion. At one place in south-east, the deposit pinches out completely for a short distance. The grade of the ore is seen to distinctly deteriorate towards south-east.

The Goa mines are multi-pit, multi-lease fully mechanised mining units.

Codli.
The open-pits have a bench height of seven metres, haulage roads of 25 metres width and an overall pit slope of 26 degrees. The Codli mines have 14 basins, of which five pits have been exhausted. The lateritic overburden is removed either by ripping or dozing, and loaded by excavators and/or wheel loaders into heavy earth moving machinery such as rigid dumpers and articulated dumpers. Hauling within the mine is also done by rigid and articulated dumpers. An ore stockpile is maintained at all times to continuously feed the processing plants.

Sonshi.
The hard laterite capping is loosened either by drilling, blasting or ripping/dozing. The soft sub-lateritic zone is excavated and transported to respective laterite, clay and ore stacks.

Bicholim.
Backhoe excavators of 1.1m3 bucket capacity are used for excavation of ROM material. Development in waste is also without drilling & blasting with the use of dozers. There are six dozers of 520, 570, 855hp, 10 backhoe of 428hp, 13 wheel loaders of 330 hp, 30 dumpers of 400hp and 6 dumpers of 350hp. All these machineries are common for Bicholim mine.

Maximum bench height is upto 6-7m. There are 10 benches in waste/OB and 7 benches in ore of which few are common due to trend of mineralisation. Working Pit top RL is 138m and bottom RL is 72m.

Codli.
Vedanta Limited has extensive ore processing facilities for upgrading the ore, which include crushing, dry screening, scrubbing, log washing, classifying, hydrocycloning, and magnetic separation with a wet high-intensity magnetic separator. The four Codli processing plants are between 1 and 18 years old and throughput capacity of the four Codli processing plants is 10 mmtpa. The processed ore is transported by road to a riverhead jetty by 10 tonne tipper trucks and then further transported by barges to the Goa ports or transhipper for onward shipment. One plant is provided with a dry circuit to process high grade ore, while the remaining four wet plants process low grade ores. The Codli processing plants undergo regular maintenance and annual repairs are conducted during the monsoon season.

Sonshi.
The material from Sonshi mine is reloaded into smaller 10-tonne trucks and transported to the plants for processing and beneficiation, which involves crushing, sc ........