PS ACID SULPHATE MATERIALS

Transcription

1 PS ACID SULPHATE MATERIALS PURPOSE AND SCOPE The purpse f this primary standard is t eliminate r minimise risk f envirnmental harm caused by acid sulphate materials including acid sulphate sils and acid sulphate rck. Acid sulphate materials can cause severe envirnmental harm t ecsystems and cause damage t structures and permanent wrks. DEFINITIONS Acid Sulphate Rck (ASR) - Gelgical units that cntain sulphide r sulphate minerals (cmmnly pyrite) which have the ptential t xidise when expsed t xygen and/r water and prduce acid that can affect structural integrity r envirnmental cnditins. Acid Sulphate Sil (ASS) - Sil r sil hrizn cntains acid sulphides r an acid sil hrizn affected by xidatin f sulphides. When sulphides are expsed t air, xidatin takes place and sulphuric acid is prduced which can mve thrugh the sil, acidifying sil, grundwater and surface water. IDENTIFYING ACID SULPHATE MATERIALS An assessment must be cnducted t determine the risk f encuntering acid sulphate material during wrks. This includes assessing whether sils cntain Ptential Acid Sulphate Sil (PASS) r Actual Acid Sulphate Sil (AASS). Envirnmental assessment dcuments are t be reviewed as part f the assessment. The assessment must als be cmpleted in accrdance with the planning apprval cnditins. The fllwing applies t the identificatin f acid sulphate materials: Trained and cmpetent persnnel (apprpriately qualified cnsultants) t undertake site investigatins and determine extent f ptential and actual acid sulphate material prir t cmmencement f intrusive wrks Sampling, analysis and classificatin f cntaminated material is undertaken by qualified persnnel A suitably qualified persn (preferably cntaminated land cnsultant) must be engaged t undertake the necessary sampling and analysis f ptentially cntaminated material. Analysis must be undertaken by a NATA accredited labratry. All areas where intrusive activities are taking place in suspected r cnfirmed acid sulfate material areas must be mapped and dcumented.

2 PS Acid Sulphate Materials (Rev ) Sectin 2 MANAGEMENT OF ACID SULPHATE MATERIALS The management f ASS is t be detailed in Envirnmental Management Plans (EMP). Where there is the ptential fr ASS, as determined thrugh the prject envirnmental risk assessment, an ASS Management Plan is t be develped, cmmunicated and implemented. It shuld include: Quality verificatin recrds and validatin sampling fr remediatin activities Identificatin/demarcatin f acid sulphate sil areas n site Establishing envirnmental cntrls t prevent site runff frm leaving the site Establishment f acid sulphate sils treatment area(s) that include cntainment measures t prevent surface r grundwater cntaminant measures Requirement t develp a wrk methd plan fr activities assciated with ASS material Sampling and testing regime that will be adpted t validate acid sulfate material befre (and if required) during the wrk activity Prcedures fr investigating, handling, treating and managing ptential r actual acid sulfate sils If a new acid sulphate sils area is identified during the wrks, it shuld be clearly demarcated and sign psted. It must be reprted t the site Supervisr and Envirnmental Management Representative immediately. An assessment f the material is t be undertaken. TREATMENT AND DISPOSAL OF ACID SULPHATE MATERIALS Where pssible acid sulphate material fund n site shuld be treated and reused depending n the level f cntaminatin and envirnmental planning cnditins. Treatment, dispsal r relcatin is t be cmpleted as per relevant state/territry legislatin including verificatin that any ffsite facilities and lcatins can lawfully receive the material. Dispsal recrds are t be generated including quantities, truck cunts, labratry results, reprts and dispsal lcatins. Spil frm knwn PASS/ASS areas will require assessment/treatment prir t dispsal. The fllwing cntrls must be included fr ASS treatment areas: ASS treatment areas are t be established away frm waterways and drains The area needs t be bunded t cntain the design rainfall event and an impermeable pad established beneath the stckpile Field ph tests n suspected ASS must be undertaken by a persn qualified and experienced in ASS testing Air expsure must be minimised with preference fr: Burying either underwater r cmpletely undergrund within 24 hurs f excavatin Transprt ff site t a licenced PASS/AASS dispsal site Cmmencement f PASS/AASS treatment based n the dsing rates prvided with the material analysis

3 PS Acid Sulphate Materials (Rev ) Sectin 3 ACID SULPHATE MATERIAL STOCKPILES AND TREATEMENT AREAS Where excavated ASS is treated and r stckpiled nsite, the fllwing actins are t be undertaken: Spil t be tested fr phf and phfox as it is excavated t classify the PASS cntent. Stckpiling f the spil t be categrised by the difference in ph. Labratry testing as required by the relevant guidelines, specificatin f planning cnditins will be undertaken by a NATA accredited labratry. Bunding t be cnstructed arund the perimeter f the designated ASS treatment area t intercept and cntain run-ff frm the area during sil treatment peratins. The bund will be cnstructed frm nn-ass material r lime treated ASS material. All excavated spil t be stred and treated within this bunded area as sn as pssible after being excavated The base f the ASS treatment area t be limed prir t placement f each layer f ASS. Respreading f agricultural lime prir t placement f each new layer f sil, and at the cnclusin f all treatment is required. The base f the treatment pad must have a minimum agricultural lime applicatin rate f 5 kg/m2. The treatment area must retain enugh strage capacity t hld any ptentially acidic waters/ run-ff frm the ASS. This is t cllect drainage water frm the treatment area in the event seepage r rainfall ccurs during and between treatment. The treatment area bund must be built t a height f 400mm Sil treatment must be undertaken as sn as pssible after the material has been excavated t limit the pprtunity fr the accumulatin r release f acidic pllutants Sil t be treated must be placed in layers nt exceeding 300mm and be thrughly mixed with the lime. The liming rate is t be determined by testing. The amunt f excavated material t be minimised, wherever pssible, t allw fr treatment f manageable quantities f AASS/ PASS material A cvered stckpile(s) f agricultural lime and hydrated lime is t be kept inside the site bundary in vlumes sufficient fr the treatment f ptential acid runff as a result f grund water r rainfall events A cvered stckpile(s) f agricultural lime, equivalent t the quantity fr 1.5 days treatment, is t be maintained at the treatment facility. This is t allw all treatment t ccur in a timely manner. The stckpile(s) t be replenished n an as required basis thrughut excavatin activities. The effectiveness f the treatment prcess must be cnfirmed by verificatin samples at rate f 1 per 500m3 r ther revised sampling rate t ensure that representative samples f the material are btained. Sampling and analysis must be cmpleted by a NATA accredited labratry in accrdance with the relevant guideline r cntract requirement. Where treatment has nt been successful, the material must be retreated The fllwing cntrls apply t nsite stckpiles f cntaminated material: Be clearly identifiable and must have signage in place Have a recrd f surce lcatin nted in n-site lg bk/site diary

4 PS Acid Sulphate Materials (Rev ) Sectin 4 Stckpiles and treatment shuld be lcated in a secure part f the site, away frm water bdies r drains and utside f fld prne areas Ersin and sediment cntrls shall be implemented t prevent the material leaving site Treatment and stckpile areas are t be demarcated, secured and signpsted t prevent in advertent cntaminatin OFF-SITE DISPOSAL The fllwing applies t the dispsal f acid sulphate material: Dispsal must be in accrdance with State/Territry Envirnmental Authrity Requirements Cntaminated material must be characterised/classified accrding t envirnmental authrity guidelines and dispsed at an apprpriately licensed facility Analysis f material fr dispsal must be prvided t the waste transprter/landfill peratr t ensure it meets the licence/site cnditins f the waste receiver Any materials being transprted interstate are required t assess transprt certificatin f bth the riginating and receiving lcatins Certain cntaminated and hazardus materials are required t be transprted by apprpriately licensed trucks accmpanied by a waste transprt certificates r recrds in accrdance with envirnmental authrity regulatins. REGULATORY REQUIREMENTS Guidelines fr the Management f Acid Sulfate materials: Acid Sulfate Sils, Acid Sulfate Rck and Mnsulphidic Black Oze (Rads and Maritime, 2005) Acid Sulfate Sils Assessment Guidelines (Acid Sulfate Sil Management Advisry Cmmittee, 1998) Acid Sulfate Sil Manual (Acid Sulfate Sil Management Advisry Cmmittee, 1998) Acid Sulfate Sil and Rck Publicatin (Envirnment Prtectin Authrity Victria (EPA Victria), July 2009) Waste Classificatin Guidelines Part 4: Acid Sulfate Sils (EPA. 2014) State Planning Plicy 2/02 Guideline: Planning and Managing Develpment Invlving Acid Sulfate Sil (Queensland Gvernment, 2002). Guidelines fr Sampling and Analysis f Lwland Acid Sulfate Sils in Queensland (Ahern, C R, Ahern, M R & Pwell, B, 1998 Sulfate Specificatin fr Structural Backfills (Reid, J M, Czerewk, M A & Cripps, J C, 2001)

5 PS Acid Sulphate Materials (Rev ) Sectin 5 State Planning Plicy 2/02 Guideline Planning and Managing Develpment Invlving Acid Sulfate Sil (Queensland Gvernment, 2002). PLANS AND FORMS Cnstructin Envirnmental Management Plan Acid Sulphate Sils Management Plan Site Envirnmental Inspectin Frm