Solid Waste Generation and Utilisation in Calcareous Stone Industry

Code No:TMS151Price:Rs2300/-Category:Industrial Safety

Summary : India possesses over 85,600 million tonnes of reserves of calcareous stones. Estimated production of calcareous stones (as on 1997-98) is 125 million tonnes and this figure is expected to cross over 188.6 million tonnes by the year 2004-5 in view of the industrial development in the country. Calcareous stone waste is generated during mining and processing of the calcareous stone. Indian calcareous stone industry currently produces around 17.8 million tonnes of solid calcareous waste per annum. The accumulated waste is of the order of 250 million tonnes. The waste is a serious environmental hazard. It adversely affects the fertility of the soil, contaminates the water resources and increases the drainage problem, besides causing serious air pollution. The increasing demand for calcareous stones in industries coupled with the extent of pollution resulting from solid calcareous waste generation, led TIFAC to commission a study (\'Solid Waste Generation and Utilisation in Calcareous Stone Industry\' TMS: 151) which looks at the different technologies available for waste management in an environment friendly manner and also how to put the waste for some beneficial use. The report takes a look at the reasons of generation, and possible measures for its reduction and utilisation through technological, managerial and policy measures

Year of Publication : 1999

Table Of Contents : Executive Summary, Introduction Calcareous stones-types, reserves, production, specifications, occurrences and industrial utilisation, Solid calcareous stone waste generation : Sources, causes, quantum and current practices, Technologies for reduction of waste generation, Technologies for optimal utilisation of the waste, Recommendations, List of Annexures, List of Figures, List of Tables

EXECUTIVE SUMMARY

Scope and Objective

Coverage

Methodology

Structure of the report

Major findings

Recommendations

Expected Impacts, if recommendations are implemented

Indian calcareous stone industry currently produces around 17.8 M. T. of solid calcareous waste : 12.2 million tonnes as rejects at the mine sites, 5.2 million tonnes in the form of cuttings / trimmings or undersize materials and 0.4 million tonnes calcareous slurry at Processing and polishing units. The polishing is applicable only to marble and flagstones. To accumulated calcareous waste is of the order of 250 million tonnes. It has become an environmental hazard affecting the land and population over a large area.

The solid waste generated in the calcareous stone industry is directly related with the production and processing of various types of calcareous stones that has drastically increased over the years. It is about 16.5% of the total calcareous stone produced in the country. The waste generated varies from negligible in case of the calcareous stone used in cement industry; 10%-20% in case of lime burning industry 20%-40% in case of building stone industry (blocks and slabs), 40%-45% in case of steel grade limestone and dolomite production industry and 65%-85% in case of marble and flag stone (Kotah stone, Cuddapaha slabs and Shahabad stone ) used in dimensional and decorative industry. Presently out of 6773 mines of calcareous stone covering an area of about 0.2 million hectares of land, only about 5400 mines are operating. The production of calcareous stone has gradually increased from 76 million tonnes (1989-90) to 97 million tonnes (1993-940 and 118.6 million tonnes (1996-97). It is expected to touch 139 million tonnes by 2000 AD and to 188.6 million tonnes by 2005 A.D.

The calcareous waste generated by this industry has accumulated over years. Only insignificant quantities have been utilised and the rest has been dumped unscrupulously resulting in environmental problem and health hazards such as:

adverse effects on the fertility of land, as these wastes are deficient in plant nutrients, Contain excessive salts and heavy metal phytotoxicants destroying young plants by sand blasting and lack in normal microbial activity.

Drainage problems, when dumped along the drainage passage.

Contamination of water resources.

Air pollution as the dry powder becomes air borne on windy days.

Problems for extension of mines, when dumped in mining area.

Wastage of valuable natural resources of calcareous stones.

Handling and disposal problems.

Recognising the urgent need to manage this industrial waste in an environment friendly manner and also to put it to beneficial use, TIFAC (Technology Information, Forecasting and Assessment Council), Department of Science and Technology, Government of India has commissioned the study.

Scope and Objective

The study aims to identify the sources, causes and the quantum of solid waste generation in calcareous stone industry and to identify optimal technologies for utilisation and reduction of solid calcareous stone waste while keeping in view the available and emerging technologies in the context of socio-economic set up of the country.

The detailed scope and objective as stated by TIFAC is:

Relationship and the importance of the specific topic to the broad area to which it belongs.

The current status of technology in the world and in the country, market (domestic and exports) sizes and their potentials.

Assessment of the technology, resource parameters such as energy, raw material, infra-structure and man power etc. to arrive at preferred technology option available in the country.

Short-term and long-term economic aspects of preferred options along with their feasibilites.

Impact of preferred options by itself and its spin-offs.

Recommendations :-

For implementation of preferred technology options – indicating critical inputs such as raw material, capital goods and human resources required and their availability, investments required to commercialise, and benefits / returns expected.

For R&D / technology development indicating the requirements of inputs and expected benefit s.

Action plan for implementation of recommendations along with indication of :

List of available technologies for Indian industry and

The agencies / groups / individuals for implementation.

Expected impact of recommendation, if implemented.

Coverage

The study has covered generation of solid waste in the calcareous stone industries in the country. Reasons for its generation and possible measures for its reduction and utilisaion through technological, managerial and policy measures.

The extent of solid waste generated in calcareous stone industry has been assessed at :-

Mining or production stage.

Processing, sorting or beneficiation stage and

Utilisation or consumption stage.

Dimensional and decorative calcareous stones (marble and flagstone), the major source of solid calcareous stone waste generation causing maximum environmental and health hazards, has been covered in detail along with possible measures for reduction and optimal utilisation of these wastes.

Other sources of solid calcareous waste that have been briefly included in the report are (a) the calcareous waste generated incidental to the mining and beneficiation of the ores of lead, zinc and phosphate and (b) some of the industries which produce calcareous waste such as iron and steel, paper, acetylene gas and chemicals etc. The management of these calcareous wastes though does not directly fall under the scope of the present study, it has been covered briefly as felt relevant to the subject of the study.

As per the current practice, in certain cases, the mining leases for rocks and minerals are granted for specified application / uses (e.g. Cement and Iron & Steel industry) and this leads to forceful rejection of quality minerals, which are not suitable for captive industry but are suitable for other applications. This is in line with the MMRD act, 1957 and is applicable only when the lease is granted for captive use. It is regretful that the State mining authorities do not allow sale such materials / minerals for other industrial applications of these forcefully rejected material and thus indirectly hampering the optimal utilisation of the valuable mineral resources of the country. Captive mine owners may be permitted to market the minerals / rocks which are not of use to them but can be gainfully utilised by other industries, but ofcourse not at the cost of the captive industry.

Methodology

The study has been conducted through intensive survey covering a number of relevant institutes / agencies viz., calcareous stone mining agencies, processing agencies and user agencies. Monitoring and government agencies have also been covered along with R&D and academic institutes. The intensive study of relevant literature, periodicals etc. has been carried out. The list of literature scanned / referred is enclosed. The International data base has also been scanned.

A list of Academic Institutes, R&D agencies, Govt. bodies, Industries etc. that have been contacted during the survey and study is enclosed as Annexure –I.

Structured questionnaire, open ended questionnaire, personal interviews have been resorted to during the field survey. Separate questionnaires were used for the following four categories of respondents.

Calcareous stone mining / processing and / or consuming units (Cw-M)

Other industrial units consuming calcareous stone (CW-G)

Other mining and processing units producing calcareous stone waste (CW-Mo)

R&D organisation / Institute, Academic Institutes and Government bodies working on calcareous stones (Cw_OIAG).

A set of these questionnaire is placed as Annexure IIA to IID. The information received were compiled, processed and analysed under various sub-heads. Missing / additional information was collected through subsequent quarries and also through available literature wherever required. Detailed discussions were held with the knowledgeable persons and experts of the respective fields for emerging technologies in the mining, processing, beneficiation and other technical aspects in utilisation of various types of calcareous stones. Foreign companies / agencies were also contacted.

Initially, less than 10% of the agencies / organisations / institutes responded to the questionnaires sent to them. After about one month’s time postal, telephonic and fax reminders were sent and it was followed by personal visits to select places. As a result of this, information was received from more than 35% of the agencies.

The information thus collected during the techno-market survey was used to evaluate and estimate the quantity and quality of various types of wastes generated at various stages in the process of mining, processing, beneficiation and utilisaion of these calcareous stones in the country. The studies were further utilised to logically conclude to find out

The causes of solid waste generation in calcareous stones industry as well as in other industries.

The ways and means to reduce solid waste generation in the calcareous stone industries.

Impact of calcareous stone waste on the environment.

The possibilities of optimal utilisation of various types of solid waste generated in the calcareous stone industry as well as in other industries producing solid waste of calcareous nature (e.g. blast furnace slag in iron & steel industry, dolomitic slurry incidental to beneficiation of lead, zinc, phosphate ores etc.).

Structure of the report

The report deals with the total size of calcareous stone industry, its importance and inter-linkages with the consumer sector. Status of mining and processing technologies are covered to develop the appreciation of these factors that lead to generation of calcareous stone waste. The introductory part is dealt in chapter one. While a brief description of calcareous stones, their occurrences and relevance to industrial development of various states in India is covered in chapter two. The type and quantum of waste generation at different stages of mining, processing and consumption together with their geographical dispersal is given in chapter three. Generation of industrial calcareous waste has also been touched upon in this chapter. The current status of the utilisation of calcareous stone waste, status of technologies, recent development and options for future are dealt with in chapters four and five. The sixth chapter concludes the report with recommendations (short term and long term) along with action plan and impacts, if, the recommendation are implemented.

Major findings

In calcareous stone industry, the modern approach to the productive cycle cannot neglect the problems, causes of generation of the calcareous stone wastes, which is a part and parcel of he whole productive process, affecting sometimes to the extent of decisive factor towards the success or failure of the project. The endeavours are thus to include possible measures to reduce the waste generation, its proper handling and utilisation. The proper management of the calcareous stone waste in the industry essentially helps to

Conserve the valuable natural calcareous stone resources.

Maintain the beauty of the landscape.

Avoid the environmental and health problems.

Solve the handling and disposal problems.

Maximum calcareous stone wastage is generated at its production or mining stage followed by processing stage, specially while processing various types of calcareous stone (marble, flagstones, lime stones etc.) for use in the building industry.

At consumption stage the calcareous waste is produced as a by product in many industries like Iron and steel, paper, sugar acetylene gas etc.

Calcareous stone waste is also generated in the production of non-calcareous minerals (like ores of lead, zinc and phosphate) of utility.

The quantum of solid calcareous waste generated in certain cases like marble and Kotahstone industries in Rajasthan are quite alarming and have already caused tremendous environmental pollution to the extent that it requires immediate remedial measures and efforts to improve upon the situation. Further delay may lead to a situation beyond control.

Solid calcareous waste generated has posed not only disposal problems but also hampered the production and processing of calcareous stones in many cases.

Modern methods of mining & processing of calcareous stones are mostly not being used. Only some big captive mines of calcareous stone for cement, iron and steel industries and some big marble mines are utilising the advanced technologies.

Calcareous stones from many deposit are being sub-optimally utilised, for some or the other reasons pertaining to administrative, mining rules and regulations, taxation structure etc.

Sometimes undesirable solid calcareous waste is forcefully generated at the place of its production to meet the specifications of certain industries located far away from deposits, requiring very long road & rail transportation. This could have been avoided or its exploitation be delayed till some user agency was identified to make use of the material of high quality being accumulated as forceful rejections.

Beneficiation of calcareous stones is exceptional than a practice in India.

Calcareous stone processing and consumption units are located at far off places in many cases, making the commercial viability of both the units at stake.

Infra-structural facilities for development of mines, processing and consumption units are not developed as per requirements.

Only insignificant percentage of calcareous stone waste produced in the industry is being utilised.

Desirable arrangements for handling and disposal of calcareous stone waste are lacking.

Recommendations

No calcareous stone is a waste. All the calcareous stone can be used judiciously as per its specifications.

By switching over to advanced technology in mining, processing and utilisation of calcareous stones it is possible not only to reduce the generation of stone waste, but also utilise the already generated solid calcareous stone waste. This will help in coservation of valuable deposits of calcareous stones and help to keep pollution under control.

Quarrying by blasting the building stones, dimensional and decorative calcareous stones, namely yellow limestone of Jaisalmer, Rajasthan and in Gujarat; flaggy limestone (Kotah stone, Shahabad stone of Cuddapah slabs) in Rajasthan, Karnataka and Andhra Pradesh; and marble in Rajasthan, Gujarat, Haryana and other parts of the country should be stopped and replaced by modern Wire Saw mining techniques to reduce the stone wastage from 60% to 85% at the production (or mining) stage itself to hardly 20% to 30%, which could further be reduced by utilising the small sized and odd shaped blocks to produce small slabs and tiles and also the same may be used for many other value added decorative articles like pen stands, ash trays, flower pots, etc.

Calcareous stones mined out or produced should be graded properly as per its physical and chemical properties and stacked separately for its proper utilisation in accordance with their specifications. It will help to keep wastage, particularly, forcefully generated waste under control at both the production and consumption stages.

India has a tremendous potential India has a tremendous potential to produce value added products like quick lime, slaked lime and precipitated calcium carbonate from waste calcareous stone and sub-optimally utilised limestones.

Micro grinding of calcium carbonate technique should be adopted to produce international standard powder of calcium carbonate for use as fillers in plastic, paper and paint industry. For this purpose calcareous stone and its waste could be used to produce the value added product which is in great demand world over.

Marble waste produced as solid fragments, powder and slurry may be used as filler in the manufacture of plastic, rubber, venyl flooring etc.

Calcareous stone slurry, obtained during polishing of stones, a mixture of calcium carbonate and silica, could successfully be used in manufacture of lime-silica bricks.

The uncontaminated marble sludge could be used as

a.	Mineral fillers in various industries (plastic, rubber, paint, paper etc.).
b.	To desulpharise the smoke of coal – fueled thermal power plants.
c.	In manufacture of cement.

Mixed sludge of calcareous stones and granite was mostly generated at big stone processing units. It could be used

a.	in manufacture of building products (bricks, blocks etc.)
b.	in the water proofing of solid waste disposal of municipalities. A mixture of the sludge, granite fragments and bentonite clay could be used as filtering agent.

Mostly, the Indian marble is dolomitic in composition and at places almost a dolomite, its waste could be beneficiated or used as such in accordance with its specifications in various industries.

Dolomitic slurry produced during beneficiation of rock phosphate, lead and zinc concentrates could also be used in manufacture of bricks for construction purposes or could also be used as soil conditioner in agriculture sector as in case of marble slurry.

Solid rock fragments of dolomite generated as waste during mining of rock phosphate, lead and zinc ore deposits may be used as railway ballast or road ballast as in case of hard, compact and massive limestones.

Blast furnace slag finds its utility in cement manufacture and also as fertiliser / soil conditioning.

Paper sludge / calcareous slurry could be recycled as carbonate material after processing.

In the present era of Economic Liberalisation, though the mineral and industrial policy have been significantly revised for the industrial development of the country, yet following suggestions are made to further improve upon the situation.

a.	Appropriate amendments in M.M.C.R. (Mines and mineral concession rules) together with administrative reforms be made, so that the minerals / rocks mined out from a leased property could be sold for their optimal utilisation for any purpose, even other than the purpose for which the property was leased out. The royalty or taxation procedure for such sale / use should be simplified and in certain cases may even be waved off, in the interest of the development of industry utilising the waste material which is being dumped at the mining or processing sites.
b.	There is still a need to unify the rules and regulation for mining and taxation in all the states of the country.
c.	"Mines" should be given status of "Industry" by extending similar facilities of financial assistance, taxation and matters of infra structure.

Calcareous stones, though available in plenty in India, should be used judiciously as these are extremely valuable raw material for many industries. High grade, low silica limestone should be used judiciously. It may be preserved for future utilisation to manufacture calcium carbide and acetylene, as and when the infra-structural facilities for manufacture of the same would be available or developed. If required L.D. grade (Linzer Dusenthal i.e. oxygen blowing grade for steel production) low silica limestone should be imported rather than exploiting a very high grade limestone deposit and generating about 55% waste at some mines like Sanu mines, district Jaisalmer and 35-40% waste at Gotan mines, Jodhpur, Rajasthan and then transporting the product to different iron and steel plants located far off from the deposits involving almost the same transportation cost as would be incurred if its imported. Similarly, limeshell and coral limestones available in southern states of India etc., wherever possible should be used for petrochemicals and if not possible at present it should be preserved for this purpose for future use.

Expected Impacts, if recommendations are implemented:

The environmental pollution problems due to calcareous stone industry would be brought under control.

The reduction in waste generation would not only boost up the economy of calcareous stone industry, but will also help to control the environmental problems as well as conserve the valuable natural resources of calcareous stones.

The optimal uses suggested for unavoidably produced calcareous stone waste will not only generate employment, but will also help the socio-economic upliftment of the local population.

The life of the deposits of marble and flaggy limestone, with present rate of consumption is expected to be exhausted within next 60-70 years, will be enhanced considerably.

Manufacturing of value added products from the calcareous stone waste will boost up the economic health of the calcareous stone industry and will bring it to the International level of competition.

Simply, utilisation of calcareous stone waste to manufacture silica-lime bricks will not only enhance the availability of building material, but will also save the top horizons of fertile clays and soil of the agriculture fields from being used in brick industry. Its direct impact on the economic and environment can not be evaluate d in terms of money, as nature takes millions of years to build one inch of fertile soil cover on the land.