2. Standardisation of Auto Sampler cum Sample Preparation Unit at Nandan Washery Dr R Dasgupta and Dr Kalyan Sen, 1999

3. Nandan Washery Designed & Commissioned by M/S Voest-Alpine of Austria, 1984 3-product Komag Jigs (Coarse & Fine Coals) Flotation Cleans to Bhilai Steel Plant for metallurgical use Sampler before the Storage cum Loading Bunker

4. Material flow diagram of Nandan washery

5. Purpose uNo arrangement for sample collection during actual loading of washed coal uQuantity of samples from sampler is not adequate Y Less load on clean coal belt

6. Objective kTo standardise the Auto Sampler cum Sample Preparation Unit kUltimate Aim u Joint sampling by producer & consumer without any external surveillance kTo evolve & Articulate practical procedure for future use, within the broad guidelines of Stipulated Standards

7. CFRI Strategy To evolve methodology through participation of Nandan, CCSO & CFRI officers Stepwise study or approach Z Preliminary planning - at washery site Z Preliminary test experiments Z Final corrective measures, data collection, collation & Statistical tests

8. Preliminary Tests Conclusion w Adjustment of double roll crusher w Change in sampler time interval w Dividing ratio (?) w Replacement of Chemical balance w Procurement of Digital balance (20 kg) for Total moisture determination

9. Test Methodology v Sample Collection and Preparation Z Sampling Points identification Z Sample collection & preparation < Ash < Total moisture

10. Sampling Points Belt SampleS 1 (Stop belt) Flap SampleS 2 * Auto SamplerS 3 Bottle SampleS 4 * discontinued at later stage

11. Sampler cum Sample Preparation S1S1 S3S3 S4S4 S 2 - Flap

12. Ash Sample Preparation P Gross Sample P Air dry & Crush to 12.5 mm P Air dry (if required oven dry at 35 deg but not more than 2 h at a time) P Reduce the sample to 2 kg P Divide into 4 parts P 2 parts (Reserve); 1 part (212 micron) & 1 part (212 micron) P 1 part preserve as check sample P 1 part divide using laboratory divider (2 samples) P Sample A 1 Sample A 2

13. Total Moisture Sample Preparation Gross Sample Air dryRecord wt. Crush to 12.5mm Reduce 2.5kg Crush to 2.8mm Divide into 4 parts Sample A Sample B RESERVE Size 12.5 mm above ? Record Initial wt. Stage 1 loss% Stage 2 loss% Oven dry 35deg not exceed 2h Record wt. Stage 3 Moist. 10g, 108deg, 2h Y N

14. Statistical Analysis H Coal is heterogeneous material H Very difficult to achieve highest level of Sampling precision H In terms of variance D 80 % is from Sampling D 20 % is from preparation & analysis H Overall precision is influenced primarily due to Sampling H Utmost importance thus need to be given for Sampling

15. Statistical Analysis Testing of Bias v Paired samples v One member is the “System” under test v Other one “Reference” Z An intrinsically unbiased sample Z To be obtained by stopping belt method v Series of differences are subjected to Statistical analysis

16. Statistical Analysis Assumptions a A normal distribution of the variable a Independence of the errors of measurement a Statistical homogeneity of the data

17. Statistical Analysis C Test for flagging outliers C Estimation of number of pairs required C Assessment of Bias C Method I C Method II C Test for significant difference from zero C Test for significant difference from B (MTB) Basic Steps

18. Common Sample Preparation Common Bottle Sample Air dry Record wt. Crush to 2.8mm Divide into 2 parts Sample A Sample B RESERVE Record Initial wt. Stage 1 loss% Stage 2 loss% Oven dry 35deg not exceed 2h Record wt. Stage 3 Moist. 10g, 108deg, 2h Divide Crush to 2.8mm Sample C Ash Divide into 2 parts