Coverage Of Piece Rate Labourers Under The Provisions Of PF

Dear All,
I am working in Construction Industry.In our Company most of the Labourers are being paid on weekly and on piece rate basis.The average earnings of a labourers is definitely more than Rs.6500/-Per Month (The statutory ceiling limit under PF is Rs.6500/-).These earnings of the labourer is from the starting of his engagement.They are reluctant to be covered under PF as they will be working only for a short period (Maximum of One Year)
I request you all for opinion and suggestions on the following :
01.Whether these labourers have to be covered under the provisions of EPF ?
02.if not,what will be the position in case if their earning fall below Rs.6500/P.M ?
03.Can we take a request letter from these workers not to cover under the Act ?
04.Whether such a request letter is legally valid ?
With Regards
N.Mohan

HI
as you said you are in construction industry and
all employees have salary more than 6500 /-
if you do not want to deduct PF of the you have to maintain Form no 11
Vikram Trivedi
PF Consultant
Mob: 8898841995

Dear Mr.Vikram,
As you said we are obtaining Form 11 from all the Labourers. Thanks for clarifying one of my queries. It will be more helpful if you can air your opinion and suggestion on others too.I require opinion more particularly on earnings as our labourers are working on piece rate basis.
With Regards
N.Mohan

Dear All,
Request you for your views please.
With Regards
N.Mohan