You said they were marked k 70, and blue/round.. if there is a coating on them, and they don't crush to fine powder, then you know you have the unabusable newer ER opanas, which suck ass.. taking opana oral, is worthless ime.. You have to sniff it, or if your an IV addict, and already bang shit.. then if your like most other IV opiate addicts, your going to bang it, for the incredible immediate rush, high, and etc... but in all honesty, doing both, I have had enough success with sniffing any opana able to be sniffied, and OP I believe if your pils are blue round and say k 70 on them, and look like almost like an oxycodone IR 30, but bigger(unless were speaking on the stupid ass giant 224s.)..
Basically, if your pill is able to be crushed with just a press of a credit card.. and has a more powdery look to it once crushed than waxy its prb an IR, byyour description sounds like you have the KVK generic IRs, type in the imprint, color, and shape on google and see what happens.. that's how you can def find out whether or not they are ER or IR.. but I believe you have the IR 5s.. and if so, your good to sniff em.. but if you do it a lot, its, as with almost any opioid, very addicting.. I'm sure, if you just sniff that one 5mg pill, you will feel it.. I could, when I was doing decent amounts of oxycodone daily in the past, and be destroyed, off just 5mg.. and if I did that much IV, I was even more destroyed..
I highly advise like methacodone said, start small, and see what happens with a 5mg up the nose.. if it works, you will know! trust me, its like a different drug completely when sniffed, than it is when taken oral.. way stronger! The first time, I ever tried opana, I got 40mg old school, abusable brand name opana ERs. way back in like 2010 or so.. and just a sliver would have me fucked up.. I was amazed at how potent and strong it was, had me extremely sedated at around just 10mg.. it was a great feeling, but I only did it on the occasion, at that time I did a lot of oxycodone, and opana was a real treat if it showed up..