Morocco - Jorf Lasfar Power Project : environmental impact assessment (Vol. 3 of 6)

-. ~~GIBB JORF LASFAR POWER PLANT ASH DISPOSAL SITE DEVELOPMENT F~ -~~~~~~~ ~~~~~~;~~- :, ~~~~t i- T 4 PHASE 2B - DESIGN OF LONG TERM SITE INTERIM REPORT NOVEMBER 1996 J96291 B  I  DOCUMENT CONTROL SHEET PROJECT: Jorf Lasfar Power Plant JOB NO: J96291B Ash Disposal Site Development TITLE: Phase 2B, Design of Long Term Slte, Interim Report Prepared by Reviewed by Approved by ORIGINAL " E S.D. Clamp R.M. Wingfield J E. Crosfield 1996__ _ _ _ _ OATS TUSIAIE innO,E AIJAUE I_ _ REVISION I SUIWtE SIGOWTIE _lOATME REVISION i . _ ..I DATE 51MURE STURE SKN^TURE |REVISION DIA EO DATE NTURE MOTUnIE U E This." ror,andinmaion orsiewich it-r s i,sprovided byGISslelyfor iymauseadreince byits Cletinpeu Gmmance f ,lB sdead ahbes under is contract with tie Client. Any adice, opins, or oonrnerndaom nwithntis report shotld be rad and eied upn ony In the contedof ch repot as a whoee. The adviceand opinions m thisn rport ar' _ P on the medonnab0n made Owv111bl to GI8 at ie date of this eport and on Cuent UK sndards, s, technooy and Omsu eon praces as at d date ofr iis fepot Foowing fina deknery of dis rpor to Si Clent, GIBB will hae no urther obhkgatirs or duty to advise tOe Chat on any nmaSem, inluding devekopment a*fean the infonnation or made. proided in t s rpot This rt has been prepared by GIB in Sir profesional capacity as Consultirg Engineers The con of tr repor do not m any w_y, pqupor tf include n maeo lega advice or opinon. Thts eport is prepared in accordance wih tie tems and eondbons of GIBBs onbact with the Client Regard should be had to Sin m. wt a ondrbons when consideing anor placing ny riance on ihs rpr Shod the Cient wh to ae i ot o a Third Payor thparts ,G myat fs dicrebon, agee toshreles proved tat (a) GIBBEs wnr agrenent is otined prior to sucha , and (b) By releaae of te report to te Third Party. tSat Third Party does not acquire any rigt. conbas, or edwerwse. whatsoer aainst GSB and GIS. acordingly, assume no dutibes, iabit or oblgatons to brat Third Party, and (c) GBB accepts no respotsibility for any lss or damge d by mi. Cint or for any cordlit of GIBBs irsad na out of Si Cierts releeof thispor totheThird Party.  a I I  CMS GENERATION CO. & ABB ENERGY VENTURES INC. JORF LASFAR POWER PLANT ASH DISPOSAL SITE DEVELOPMENT PHASE 2B DESIGN OF LONG TERM SITE INTERIM REPORT November 1996 J96291B Revision 0  I I  JORF LASFAR POWER PLANT ASH DISPOSAL SITE DEVELOPMENT PHASE 2B DESIGN OF LONG TERM SITE INTERIM REPORT CONTENTS Section Description Page EXECUTIVE SUMMARY 1 INTRODUCTION 1-1 2 REGIONAL AND SITE CHARACTERISTICS 2-1 2.1 Regional Physiography and Geology 2-1 2.2 Historical Summary of Port Quarry 2-2 2.3 Topography of Port Quarry 2-3 2.4 Geological and Hydrogeological Conditions at the Site 2-4 2.5 Groundwater and Site Sensitivity 2-9 3 METEOROLOGICAL DATA 3-1 3.1 General 3-1 3.2 Rainfall 3-1 3.3 Temperature 3-1 3.4 Wind 3-2 4 WASTE STREAM 4-1 4.1 Waste Stream 4-1 5 SITE END USE 5-1 5.1 Site End Use 5-1 6 CONCEPTUAL DESIGN 6-1 6.1 General 6-1 6.2 Voidspace and Landform 6-1 6.3 Settlement and Compaction Requirements 6-2 6.4 Operational Ufetime 6-3 6.5 Site Preparation and Design 6-3 6.6 Site Access and Facilities 6-5 6.7 Site Restoration 6-6 7 OPERATIONAL PROCEDURE 7-1 7.1 General 7-1 7.2 Bund and Lagoon Construction 7-1 7.3 Ash Conditioning 7-1 7.4 Placement Method 7-2 7.5 Dust Control 7-4 7.6 Monitoring 7-4 J96291B November1996 jorf4as2binjO.doc Revision 0  8 PREUMINARY COST ESTIMATE 8-1 8.1 General 8-1 9 IMPLEMENTATION SCHEDULE 9-1 9.1 General 9-1 10 RECOMMENDED FURTHER INVESTIGATIONS 10-1 10.1 General 10-1 10.2 Boreholes and Piezometers 10-1 11 DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS 11-1 12 REFERENCES 12-1 Figures 1.1 Jorf Lasfar Location Map 1.2 Long Term Site Location Map 2.1 Geological and Hydrological Features 2.2 In-fill Material 2.3 Predicted Flood Levels 2.4 Groundwater and Electrical Conductivity Levels 4.1 Ash Stream for Long Term Site 6.1 Restoration Surface 6.2 Operational Phases 6.3 Operational Phase 1 (Showing First Three Cells) 6.4 Section A-A' Through Long Term Site 6.5 Lagoon Conceptual Design 6.6 Perspective Views of the Long Tern Site Before and After Disposal 9.1 Preparation Contract Schedule 9.2 Operational Schedule Tables 2.1 Composite Lithological Log of Port Quarry 2.2 Geochemical Summary 3.1 Monthly Total Rainfall For Safi J9611 B Novenber 1996 jorft-ls_2WLrO.doc Revision 0  3.3 Mean and Maximum Temperatures For Safi 8.1 Cost Estimate Plates 2.1 Port Quarry Entrance and Stockpiled Soil Overburden and Madl Waste 2.2 Port Quarry Panorama Viewed Northwards 2.3 Backfilled Soil Overburden on Westem Side of Quarry 2.4 Logged Section of the Lower and Upper Quarry Faces 2.5 Oil Contamination on Northem Side of Quarry 2.6 Oil Residue Deposited Following Recession of Surface Water J96291B RenNove 1996 rfas\2bhrO.doc Rev,o 0  I  EXECUTIVE SUMMARY GIBB Phase 1 studies recommended the Port Quarry, located some six kilometres from the Jorf Lasfar Power Plant, as the preferred location for the long termn disposal of ash. Desk studies, reconnaissance-level engineering geological mapping, and some limited soilgroundwater sampling and testing have now been carried out. No new topographical survey and no new intrusive investigations were able to be carried out at this stage. Interpretation of the available data has been undertaken, and our preliminary findings are presented in this Interim Report. We consider the site to be feasible for the long term disposal of ash to land by the haul and tip method. The site is considered to be sensitive with respect to any potential groundwater impacts. However, disposal to the site will have minimal impact on groundwater, providing that certain engineering works are undertaken and operational controls are put in place. In combination with ash disposal at the Intermediate Site (refer to GIBB report, entitled "Phase 2A, Intermediate Site, Final Design Report" of November 1996), the Long Term Site will be able to accommodate the CMSIABB minimum requirement of thirty years of ash production. A layout of the Long Term Site and a restoration drawing are included in this report, together with preliminary design details. Operational and monitoring requirements are outlined. A preliminary cost estimate and implementation schedule have also been prepared. Redevelopment of the Long Term Site for industrial or other uses is considered entirely feasible after disposal operations are completed and provided that adequate controls are applied during ash disposal operations. J96291 B Novemnber 1996 jorf-lasognkjo.doc Revision 0  I  I INTRODUCTION This report is prepared for CMS Generation Co. (CMS) and ABB Energy Ventures Inc. (ABB) in accordance with Sir Alexander Gibb & Partners Ltd's (GIBB) faxed proposal of work for an interim report on ash disposal at the preferred Long Term (Port Quarry) Site, reference SDC/AI 10/J96291 B of 27 September 1996. The Long Term Site will not be immediately available. CMS/ABB require an intefmediate site for ash disposal with a design life of at least three years from the date of CMS/ABB commencing operation of the Jorf Lasfar Power Plant. An interim report on the design of a separate intermediate site for ash disposal was submitted to CMS/ABB in October 1996. CMS/ABB require an environmentally sound, long term site for permanent ash disposal which, in combination with the Intefmediate Site, provides for a disposal period of at least 30 years. Preliminary conclusions regarding the long temn disposal of ash were given in the Phase I - Preliminary Studies Report, prepared by GIBB and dated October 1996 (J96291A Rev. 2). The Port Quarry was identified in that report as the favoured site for long term ash disposal and recommendations were made for the necessary Phase 2 studies. The Port Quarry is located some 6 km to the north-east of the Jorf Lasfar Power Plant (see Figures 1.1 and 1.2). This Interim Report presents findings of the initial Phase 2 studies with particular emphasis given to those topics on which CMS/ABB require advance information prior to completion of design and issue of a final report. These topics include: a conceptual design; a calculation of available voidspace; engineering and operational requirements; a preliminary cost estimate; and a preliminary implementation schedule. The findings of this report are based upon topographic surveys of the Long Tern Site performed in 1982 and 1988 by others, and the results of a drilling investigation performed by Tractebel in 1989. Regional and local desk studies were commissioned on the project area and these data, where applicable, are incorporated in this report. Engineering geological reconnaissance-level mapping of the Port Quarry has been carried out by GIBB. Samples of the groundwater beneath and surrounding the site were taken from a spring and from public wells and have been tested. In addition, tests have been conducted on silt, sand and gravel materials at the site which have the potential for reuse as cover material. Design concepts have been developed, comprising preliminary layouts, voidspace calculations and restoration options. Operational concepts and a preliminary cost estimate have been prepared. The information provided in this Interim Report is based on the results of the field investigations and desk studies completed to date. Some of the information required to make substantiated conclusions and recommendations was not available for this study. The conclusions and recommendations provided should therefore be considered preliminary in nature. Nevertheless, these are backed up by sufficient information and data as to be useful for planning purposes. J96291B November 1996 j0rf4asi2bhr0.doc Reviion 0 1-1  I  2 REGIONAL AND SITE CHARACTERISTICS 2.1 Regional Physiography and Geology The Jorf Lasfar Power Station and Port is situated within the El Jadida Province, which extends inland from Azemmour in the north-east to Safi 110 km to the south-west. The northem boundary coincides with the River Oum Rbia, which rises in the Middle Atlas Mountains, and is tidal near Azemmour (Figure 1.1). The Province is characterised generally by a series of broad plateaux varying in elevation from 125 m to 200 m above mean sea level (AMSL). Jorf Lasfar is located along the westem coastal margin of the El Jadida Plateau to the south-west of Mazagan. The westem edge of the plateau exhibits a typical karstic terrain at an elevation of 50 to 60 m AMSL some 2 to 5 krim inland. This terrain comprises mainly bedded limestones with only a thin soil cover, due to extensive wind erosion. To the north-west, the ground level falls gradually towards the Atlantic Ocean. A relatively steep slope is developed about 0.5 km from the shoreline and represents a former cliff line of Plio-Quatemary age. The regional geology of the El Jadida Province comprises a folded Pre Cambrian/Lower Palaeozoic basement overlain successively by Mesozoic, Tertiary and Quatemary strata. The basement, which outcrops in the south of the Province, includes schists, dolomites, siltstones, granites and rhyolitic lavas. The succeeding Triassic basalt lavas and Jurassic sandstones outcrop mainly along the banks of the River Oum Rbia. The Cretaceous strata are subdivided into a lower division of Neocomian age and an upper division of Cenomanian age. The Neocomian is represented by red calcareous clays which occur north east of Safi and west of Mechra-Benabbou. The Cenomanian (Upper Cretaceous) strata are confined mainly to the El Jadida Plateau. The strata comprise a local basal conglomerate and an overlying sequence represented by calcarenites, marty limestones, marts and quartz sandstones. The Tertiary strata occur as a broad north-east to south-west trending strip up to 20 km wide which broadens in the vidnity of Safi and comprises mainly sandy marts and red clays. The succeeding Quatemary deposits predominate to the east of the Tertiary outcrop and also occur as a thin strip along the coast. The deposits indude uncemented and cemented calcareous dune sands and calcretes, together with alluvial muds along the permanent river courses. The karstic terrain is also characterised by a thin surficial layer of tufa which has been precipitated on much of the limestone outcrop. J96291B November 1996 jo4f-4as12bmt_0.doc Revision 0 2-1  2.2 Historical Summary of Port Quarry The history of limestone extraction at Port Quany, officially called Jorf Lasfar Quarry, has been determnined from the following data sources: * detailed site reconnaissance undertaken by GIBB in October 1996 * plans of the proposed extraction and operating quarry submitted to the Moroccan Ministry of Public Works and Communications in 1978 and 1982, respectively * report prepared by Tractebel (1989), which included a then recent plan of the quarry and the results of ground investigations conducted by LPEE in 1975 for the Secondary Ports Authority Umestone extraction commenced in 1977 at Port Quarry to provide armour stone for the construction of the breakwater at Port Jorf Lasfar. According to plans submitted to the Ministry of Public Works in 1978, the proposed boundaries of the quarry comprised an area of 750 m x 750 m, with the processing plant and site offices being located to the west. Excavation commenced with the removal and stockpiling of soil overburden along the north- south tract to the west of the quarry. A bench was then developed at about 9 m below ground level, remnants of which are still evident in the north-east and north-west comers of the quarry (Figure 2.1). The marly limestones near the top of the upper face, being relatively weak and closely bedded, were unsuitable for their intended usage at Port Jorf Lasfar and were stockpiled to the north-west of the quarry. The underlying massive mardy limestones, however, are strong with widely spaced vertical joints and occur as large equidimensional blocks which were suitable for use as armour stone. Subsequently, a lower face was developed in the crystalline shelly dolomitic limestones which are mainly massive and strong to very strong and hence suitable for the Port construction works. These faces were progressively worked eastwards with the subhorizontal quarry floor at 36 to 40 mAMSL. The summary borehole logs suggest that the interface between the shelly limestones and an underlying marly limestone corresponds to the level of the quarry floor. Exploitation of stronger limestones at greater depths would have necessitated the removal and stockpiling of these marly limestones and groundwater lowering to maintain dry conditions during quarry operations. A comparison of the quarry plans prepared in 1982 and 1989 indicates that some limited backfilling of the quarry along the south-westem and southem faces took place after 1982 (Figure 2.2). This backfill comprises soil overburden and mart waste which was previously stripped from above the usable rock. A comparison of these plans also indicates that limestone extraction between 1982 and 1989 was limited to a 40 m advance of the lower face in the north-east comer of the quarry and hence, active rock quarrying probably ceased soon after 1982. Since 1989, some reworking and extraction of marl waste has been carried out on a limited scale adjacent -o the quarry entrance (Plate 2.1). In addition, localised tipping or dumping of mixed quarry waste, reinforced concrete and limestone boulders has taken place along the westem and southem margins of the quarry. A large fenced compound on the westem side, possibly used for the storage of vehicular plant and explosives, has also been demolished but J96291 B November 1996 jorf4aslin1tjO.doc Revision 0 2-2  the concrete foundations are still visible. A panoramic view of the Port Quarry is presented as Plate 22. 2.3 Topography of Port Quarry Three topographical surveys are available of the area as follows: * 1:5 000 scale mapping prepared for the Ministry of Public Works in 1977 * 1:1 000 scale mapping prepared for the Ministry of Public Works in 1982 * 1:2 000 scale mapping prepared for the-Office National de L'Electricit6 (ONE) in 1988 The maximum dimensions of the quarry are about 700 m by 700 m and according to the topographic survey in 1988, the total area is 49.5 hectares. The face height from the base to the crest of the quarry varies from about 10.5 m in the north-west to about 18 m in the north- east. The elevation of the quarry floor decreases from 40 m AMSL in the south-east to 36.5 m AMSL in the north, which corresponds to an overall northward gradient of 1 in 185. The 1982 survey included levelling of the quarry floor at approximately 20 m centres as well as levelling of the surviving remnant of the bench and around the crest of the excavation. The quarry plan presented in the Tractebel report (1989) includes only a few elevations for the floor. Closely spaced levels are recorded, however, at the intersection between the floor and the lower face, along the lower bench and around the quarry perimeter. This later plan also includes the distribution and levels for the backfilled soil overburden (Plate 2.3) and marl waste subsequently placed along the westem and southem margins of the quarry. The tipping of quarry waste on the floor and limited excavation of marl waste near the entrance both post-date this most recent plan (Figure 2.2). A topographic map of the quarry floor has been prepared combining the available information for the purposes of this report. The map incorporates the closely spaced levelling data presented on the 1982 survey. The contours have been interpolated at 0.5 m intervals and transposed onto the 1989 plan. The levels for the quarry floor shown on the 1989 plan are consistent with the earlier interpolated data. The combined plan uses the 1989 data for the quarry faces and perimeter together with the contoured floor, based on the 1982 data. The contours for the quarry floor have been constructed using the software package, Surfer. This combined plan has been used as a base map for plotting a variety of information: geological and hydrological data; the distribution, type and volume of potential borrow materials around the quaffy perimeter, estimates of quarry waste on the floor; and the restoration surface. These applications of the base map are discussed in the relevant sections of this report. J9629t1B NHoveb 1996 jorf4wbd_rO.doc Revision 0 2-3  2.4 Geological and Hydrogeological Conditions at the Site 2.4.1 General The geological and hydrogeological conditions at Port Quarry have been determined from the results of previous ground investigations in the area, reconnaissance mapping undertaken by GIBB in October 1996, and subsequent well monitoring. Ground investigations were carried out by Laboratoire Public d'Essais et d'Etudes (LPEE) in 1975 and comprised 16 cored boreholes, which were drilled to depths up to 38 m and located up to 3.25 km from Port Quarry. Ten piezometers were installed to monitor water levels. Summary geological logs were prepared along three alignments, which indicate that the sequence comprises interbedded limestones, marly limestones and marls, locally overlain by tufa and capped by soil overburden. Fossiliferous and siliceous units were recorded, together with crystalline limestones. The sequence is dominated by fractured and permeable limestones and marly limestones, which represent the local aquifer, whilst marls were only encountered in three boreholes. Marls or marly limestones, which occur in the deeper boreholes, may be relatively impermeable compared to the underlying rock types and therefore may represent a local aquiclude. The summary logs indicate a lack of lithological continuity between boreholes which may be due to: * lateral facies changes and/or erosion during accumulation of the carbonate deposits * tectonic displacements along faults * inconsistent identification of carbonate rocks The geological and hydrogeological reconnaissance was undertaken by GIBB to determine: * the accuracy of existing topographic surveys (as described in Section 2.3) * the sequence of lithologies and their lateral continuity around the quarry * the location, intensity and orientation of faults, joints and fissures * the character, distribution and quantities of materials used as backfill around the quarry perimeter and floor * the distribution of former and existing surface water, together with the location of springs * the evidence of deleterious materials which may cause potential pollution of the aquifer J96291B November1996 jorwf4sslAirO.doc Revisn 0 2-4  2A.2 Geology of Port Quarry A representative geological sequence was logged in the south-east comer of the quarry (GR 286.480N, 202.320E). As the majority of the quarry faces are subvertical to vertical, additional geological data was recorded and compiled as a composite summary log (Table 2.1). The general sequence comprises a lower and an upper division, separated by a slight angular disconformity (Plate 2.4). Quarrying was advanced on two faces, which correspond to these divisions, and the intervening bench coincides with the disconformity. The lower division comprises mainly moderately strong to strong, thinly bedded, highly fossiliferous, medium and coarsely crystalline dolomites with subordinate, strong, finely crystalline, dolomitic, marly limestones. The coarsely crystalline dolomite is characterised by abundant intemal moulds of whole gastropods and lamellibranchs, which indicate dissolution of the hard parts, probably during the dolomitisation process. This replacement of calcium carbonate, probably precipitated as aragonite, by dolomite is accompanied by a volume reduction and a consequent increase in porosity. These limestones also exhibit current bedding with foresets inclined at up to 30