HNBR ( Highly Saturated Nitrile ) has better wear and abrasion resistance than standard NBR (Nitrile Rubber). It also exhibits improved heat aging in the 300 F range Vs standard Nitrile, 250 F. Low temperature range is - 40 F for both materials. Both have similar chemical compatibility but I do not have any information handy for Bitumen Froth. You should check a Compass Fluid Compatibility guide or check the MSDS sheet, they sometimes include recommended elastomers. I will post the compatibility at a later date if I can find it.