Well it depends which way you look at it. I have seen these sort of things but they were "how to " something other than get a job in the mines. I can't say I've ever brought anything like that so no idea if the info within is useful and how useful.
Now if this bloke is in the mines and getting the big salary then he shouldn't need to be selling those things anyway you would think. But of course human nature has it that most people are attracted to easy money, it could be just that for him....besides if you have something to sell that a large number of people could want to buy, even if you're selling for a small amount it could all add up pretty quick, and if you only have to write a guide once well I can see why someone would do it. Besides as long as people are getting something for their money it's not illegal or a scam.
So I don't think it's a straight out scam but I would be skeptical on how useful the information is going to be to you personally, and if it's worth whatever the cost is (I'm guessing around $30-$60?
For example if you don't have any skills that apply to mining it might tell you to go to tafe do a course and acquire particular skills...but you already know that anyway! It would probably tell you some common employment agencies to sign up with (ones like Seek for example) which you can probably find online yourself.
Of course the info could be very useful for someone who is not familiar with the industry at all and has no idea where to start. But maybe not so much for someone who already knows a fair amount, is already subscribed to employment agencies but just not having luck.
If you are trying to get a foot in what type of work are you looking to do?
You should note that Mining doesn't necessarily pay heaps more than working a standard job, it's just the hours which add up! For example cleaning or something not particularly skilled, say you got $20/hr, you work 9 days on and 5 days off, 12hr shifts, in that 2 week period you would have earned 9 x 12 x $20 = $2160 Now in the same 2 weeks if you were working for the same wage on a 9-5 normal 8hr day, 5 days a week, you would have earned $1600.
Skilled jobs can command quite great salaries though! And mining is certainly a lifestyle in itself.
My Hubby is a Surveyor in the mines, he always keeps an eye out at what jobs are going around in his field through various online employment agencies like Seek. Like others have said you could probably get useful pointers off here rather than buying that guide.