I have one raw file contains system:

$file my.raw

my.raw: x86 boot sector; partition 1: ID=0x83, active, starthead 1, startsector 63, 64259937 sectors; partition 2: ID=0x5, starthead 254, startsector 64260000, 2843505 sectors

try

$mount -o loop my.raw /mnt

mount: you must specify the filesystem type

Solution:

$mount -o loop,offset=32256 my.raw /mnt

Root:

The number too big for calculations, so set offset here.