How to mount this dd disk image?

I have a ubuntu server where we had a raid1 array of 2 physical hard-drives. Recently the raid array has ceased to mount, I was doing the backup of the data on it with rsync and it begun to give me input/ouput errors half-way through the backup, upon restarting the computer the raid array would only mount in read-only mode and the directories inside almost all showed ???? for the file permissions. A 3rd restart left me in the position I am now where the raid array will not mount at all. It appears that one of the physical drives failed as the raid array was degraded, showing 'U_'.

I have now used dd to make a copy of the disk partition like so:

dd if=/dev/sdc | pv | ff of=/media/extharddrive/sdc_copy/sdc.img

However this finished with the image file only being around 700GB even though the data stored in the raid array should be about 2.4TB. When I try to mount this image to see what data it has on it like so:

sudo losetup --partscan --find --show sdc.img

it gave me the output

/dev/loop0

I then attempted to mount this like so:

sudo mount /dev/loop0 /mnt

and it gives me the output:

NTFS signature is missing.
Failed to mount '/dev/loop0': Invalid argument
The device '/dev/loop0' doesn't seem to have a valid NTFS.
Maybe the wrong device is used? Or the whole disk instead of a
partition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?

If I run fdisk -l sdc.img I get the following:

Disk sdc.img: 797.4 GiB, 856188198912 bytes, 1672242576 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot Start        End    Sectors Size Id Type
sdc.img1   *        1 4294967295 4294967295   2T ee GPT

How can I go about mounting this disk image to get my data off? Any other suggestions for attempting to recover the data?