Cenvat Credit ??

Dear Sir,
I need your guidance on followin query.

We are Milk Dairy plant producing exempted(GHEE) as well as excisable products( Lactose and Casein)-
We took cenvat credit on steel items 'inputs'like alluminium sheets,steel sheets,pipes and angles etc. bought for construction of capital items(Milk Silos (T Chapter 73),Supporting structures,Steel Sheds for milk intake docks
The deptt has  disallowed cenvat credit on these 'inputs' used in manufacturing of capital goods.

-They cited that milk silos are not Goods so no cenvat credit allowed as this are not 'capital Goods'
-They dissalowed Cenvat Credit on inputs( pipes,angles etc) used for supporting structures etc.
Please advice.

Thanks & Regards
Anoop Garg
9878614378
Chandigarh