In the periodic table, U is the first member of group VI B and Th is the last element in group IV B. The average abundance of U and Th in the Earth's crust (upper part) is about 2 and 8 ppm, respectively, with the value for Th/ U between 3 and 4. Their average abundance in the deeper parts of the Earth, namely mantle and core, is much less, since all three radio elements [U, Th and K (40K) )] are gradually concentrated in the crustal part.
Thus, by counting the beta or gamma rays emitted by some of the daughter products of U or Th, the amount of the parent in the sample is deduced.
Primary and Secondary Atomic (Radioactive) Minerals
The sorption capacities of organic and inorganic matter appear to increase with increasing pH values to ~8.5, with maximum adsorption in the pH range of 4.5–7.5 for the former and 4.5–7.5 for the the second.
U- and Th-bearing Accessory Minerals
Location and Identification of Atomic (Radioactive) Minerals
Location of RM in a rock sample is thus performed by the technique "radioluxography (RLX)" or "solid state nuclear detection (SSNTD)"; the latter is a modified and easy version of the former. Before the exposure, an indicator (U6+-bearing solution made from uranyl or secondary U minerals) is put as small differently shaped spots in different corners of the sample to recover the original position of the two during the exposure, making it easier to match. The density of the alpha spores per unit area is directly proportional to the content of U and Th, or the intensity of radioactivity.
These traces aid in both the location of the RM with its shape and indication, at least qualitatively, of the intensity of radioactivity within it.
EXPLORATION FOR ATOMIC (RADIOACTIVE) MINERALS
Nature of Exploration
Using the bulk density of the ore and the underground data on the surface extent and grade of mineral content, the ore reserves in different blocks of a deposit are estimated. A suitable flow sheet is established by repetitive ore-working operations on the Run-Of-the-Mine (ROM) ore. The mill can either be located close to the mining area as in the case of the underground uranium deposits at Jaduguda and nearby places in the state of Jharkhand, and open pit mining of monazite (Th)-bearing coastal sands as at Chhatrapur in Orissa, or at a further distance.
The decision depends on the environmental, ecological, infrastructural, socio-economic and related factors in the area of mining.
MAJOR DEPOSIT-TYPES OF ATOMIC (RADIOACTIVE) MINERALS, WITH INDIAN EXAMPLES AND RESOURCES
- Occurrence of Atomic (Radioactive) Minerals in diverse Rock types
- Major Types of Uranium Deposits in the World
- Indian Uranium deposits: Of the above 15 types, the types of U-deposits established so far by AMD in India are: (i) hydrothermal (vein and disseminated), (ii) sandstone, (iii)
- Hydrothermal (Vein and Disseminated) type: This type accounts for much of the uranium resources in the country. It mainly occurs in the Singhbhum shear zone (SSZ) in the
- Sandstone type: The sandstone type uranium mineralisation occurs in (i) the Upper Cretaceous (~100 Ma) Mahadek sandstone in the Domiasiat-Wahkyn area in the State of
- Other types: These include: (i) The pyriteferous quartz-pebble conglomerate (QPC) type at the base of the Dharwar Supergroup and overlying the Archaean basement at
- Thorium deposits
- Atomic (Radioactive) Mineral Resources in India
Hydrothermal (veined and disseminated) type: This type accounts for a large portion of the country's uranium resources. It occurs mainly in the Singhbhum Shear Zone (SSZ) in the uranium resources of the country. It occurs mainly in the Singhbhum shear zone (SSZ) in Jharkhand state and to a limited extent in Gogi in Karnataka state.
In addition, U is recovered as a by-product of copper from tailings from the copper deposits at Ghatsila and Rakha in the southeastern part of the SSZ, while Ni and Mo are recovered as by-products during the extraction of U at Jaduguda. It occurs in the northeastern part of the intra-cratonic intermediate range of Andhra Pradesh. It occurs in the northeastern part of the intra-cratonic Middle Proterozoic Ma) Cuddapah Basin, on either side of the unconformity between the basement biotite granite and its overlying Srisailam/Banganapalle quartzite.
Stratabound, carbonate type: This deposit hosts phosphatic silicate dolostones of the Vempalle Formation, along the southwestern margin of the Cuddapah intracratonic basin in the state of Andhra Pradesh. -mineralization in these is mainly in the form of detrital uraninite, tucolite, brannerite and thorite, which contains Th. In addition, Nb-Ta deposits in the form of pyrochlore-microlite occur in the carbonatites of the Sung Valley (Meghalaya) and Sevattur (Tamil Nadu).
Deposits of Rare Earths, in the form of the minerals xenotime and monazite, occur in the river beds of the Siri River in Jashpur District (Chhattisgarh) and Deo River in Gumla District (Jharkhand), besides in the apatite ( RE-bearing)-magnetite veins at Kanyaluka, Singhbhum district (Jharkhand) (Fig. 7). Uranium mineralization in these deposits is mostly in the form of uranite, pitchblende, kist and brannerite/U-Ti oxide.
HIGH-TECH INDUSTRIAL APPLICATIONS, SUPPORTED BY U, Th, RARE METALS AND RARE EARTHS
Other very attractive aspects of nuclear energy are: (i) its very high calorific value, compared to other fuels; In terms of economics, although building a nuclear power reactor requires higher capital costs, over a long period of 25-40 years of its operation, the cost per unit of electricity produced (even after including costs for radioactive waste treatment) is comparable to that from a coal-based plant. Given these, there is a growing preference for nuclear power generation in many parts of the world.
In countries such as France and Lithuania, the contribution of nuclear energy to the country's total electricity production is >75%. India is one of the few countries in the world that uses the complex 'nuclear fuel cycle'. World electricity generation, with % contribution from major resources (Source: "Nuclear Power in the World Today", December 2001, World Nuclear Association).
Following is the summary of successive steps of the `Nuclear Fuel Cycle' with respective operating units of the Dept. Nuclear Electricity Generation (in %) in different countries (Source: 'Nuclear Power in World Today', Dec. 2001, World Nuclear Association ). Conversion of Geelkoek to UF6 and Fuel Manufacturing: Fuel is produced as pellets, packaged in circalloy tubes and transported as bundles to various nuclear power reactors - Nuclear Fuel Corporation (NFC); NFC makes two types of fuel bundles viz. i) 19-element bundle, each with 15 kg of high-density UO2 pellets for 220 MWe PHWR, capable of generating 0.64 million units of electricity; and (ii) 37-element bundle, each containing 22 kg UO2 pellets for 540 MWe PHWR, with a capacity to generate 0.926 million units of power, besides enriched UO2 fuel assemblies for two boiling water reactors at Tarapur.
Electricity Generation: At Nuclear Power Reactors located at Kalpakkam, Kota, Narora, Kaiga, Tarapur etc., at heavy water Pressurized Heavy Water Reactors (PHWR) (from Heavy Water Corporation plants like in Manuguru, Tuticorin, etc.) as moderator and natural U as fuel (Candu type); and at Tarapur with enriched boiling water reactor (BWR) fuel - Nuclear Power Corporation of India Ltd. On 6 March 2005, the 540 MWe PHWR Tarapur-4 nuclear power plant came into operation making the total number of nuclear power plants in operation as 15 with an installed generating capacity of 3310 MWe.
FOSSIL FUELS
COAL – LIGNITE 1. Introduction
- Classification and Constitution
- Origin, source materials and conditions of accumulation-formation
- Places and Conditions of Accumulation: Distribution of many individual coal seams implies swamp accumulation on (i) broad delta and coastal plain areas, (ii) subsiding
- Indian scenario
- Coal Production: After the nationalization of coal-mining in 1973, there is a substantial increase in the production of coal with time, viz., from 2 Million tonnes (Mt) in
- Future Strategy in the light of positive and negative aspects of Indian coal-lignite
It is an accumulation of partially decomposed vegetable matter and represents the first stage in the formation of all coals. Due to its high moisture content, it loosens or disintegrates after drying in the air. Most coal resources are limited to (i) and they are located in the eastern and southeastern parts of the country (Fig. 16).
The major Gondwana coalfields are spread in the states of Jharkhand, Bihar, Orissa, Madhya Pradesh, West Bengal, Andhra Pradesh and partially in Uttar Pradesh. The small tertiary coalfields are mostly in the northeastern states of Assam, Meghalaya, Arunachal Pradesh and Nagaland, with some in the Jammu area of the state of Jammu and. Lignite occurs mainly in the States of Tamil Nadu, Puducherry, Gujarat and Rajasthan, with minor deposits in the Kashmir Valley and Kerala.
Although resource-wise, small, Tertiary coal and lignite constitute an important source of energy in the coal-starved southern, western and northern parts of the country (Acharyya op. Thus, lignite forms an important solid fuel resource in the southern and western parts of Mannargudi Country & Bahur (Eocene and Oligo-Miocene) 26,154 Gujarat Many in the Iachcha, Bhavnagar, Surat and Bharuch.
Methane is a saturated hydrocarbon and its formation begins with the onset of coalification of plant deposits in the marshes. In light of this, the future exploration strategy in this sector should consider:
OIL - NATURAL GAS 1. Introduction
- Constituents, Types and Properties of Oil
- Origin of Oil and Gas
- Features of Oil-finding, Drilling and Production
- Natural Gas and Other Associated Products
- Uses of Oil and Gas
- Indian Scenario
- Future Strategy in Exploration and Exploitation of Oil-Natural Gas-Gas Hydrate
In India, the first commercial oil was discovered in 1889 in the Upper Assam area. The establishment of the Petroleum and Natural Gas Commission (now the Corporation, ONGC) in the mid-1950s spurred much-needed oil exploration in the country. In addition to hydrostatic head, other factors affecting pressure are: (i) weight of rock, oil-bearing shales, (ii) diastrophism, (iii) expansion force of confined gas, (iv) pressure due to formation of oil and gas, (v) temperature gradient and (vi) mineralogical changes in oil reservoirs.
Diastrophy and consequent metamorphosis may gasify or even carbonize the oil contained in the strata (Bateman op. cit., 669-672). Oil can be used in crude form for fuel oil [~19,000 Btu (British Thermal Units) per pounds compared to ~13,000 for coal], but most of it is refined to its constituents. As mentioned earlier, the first commercial discovery of petroleum in India was made in 1889 in the Upper Assam Basin.
For more than 115 years, the dedicated efforts of petroleum explorationists (using mainly geological and, for the last few decades, both geophysical and geochemical techniques) have identified the country's enormous hydrocarbon potential. In contrast to this pattern, in the Indian basins, more than 97% of the hydrocarbon discovered is from the Cenozoic and about 3% from the Mesozoic. Gas hydrate has been given a prominent place in oil-natural gas exploration in recent years.
The high bacterial population in the gas hydrate zone also supports methane formation from bacterial decomposition of organic carbon. In this scenario, the future strategy in the exploration of oil-natural gas-gas hydrates should aim to prove their resources and build their reserves in place at an accelerated pace.
