Actually you make 0 isk per hour mining (although you might make some isk defending yourself against rats) . When you mine you get minerals that you then sell (or manufacture into something to sell) via the market for isk.

Mining is a bad example for using as an argument as to why making isk in EVE is easier then making isk in Dust. Mining is a way to provide a service to someone that has isk by trading them something you had the skill to get. It is entirely dependent on two things - a free market economy to allow you to quickly and easily sell the minerals, and the value of those minerals as determined by the free market. If players decided at some point that the value of the minerals you mine was 0 then mining would be a 0 isk per hour activity.

Similarily in Dust if we can sell our services to someone who has isk via the free market then isk per hour would be a calculation of how valuable our service is and how quickly and efficiently we can provide it. If being able to take over a planet in an hour is worth more than two Orca loads of highsec minerals then a free market will reward a competent Dust squad more then a highsec mining operation. The key thing to note that it will be players participating in the market that will determine this and not some dev updating a loot table in a database.

Activities like mining, PI, industry, market manipulation, etc all generate 0 isk and probably should not be used as arguments to put up walls to separate EVE/Dust economies. If anything they would support arguments to allow a free flow of isk since they show that services supported by a free flow of isk allow for a wide variety of lucrative professions - including presumably being able to shoot a drop suit in the face mask.. The key would be having a solid, competitive way to sell that service on an open market - which I don't see yet in Dust (or even EVE atm - imho mercenaries in EVE are not well supported despite several attempts).

A better argument for separating the economies would be to focus on the actual isk generating activities. For Dust this would be running missions - lets go with 500 isk per hour as a rough gestimate. This currently is the only option - but maybe there will be more in the future. It also is not clear to me all the factors that go into isk generation - correct me if I am wrong but I think the value of isk generated in a Dust mission is dependent on the overall isk value of items used in the mission? If this is true then the longer Dust 514 runs the more isk per hour a player could reasonably expect to make. Compare this to Missions/Ratting/Incursions in EVE (http://wiki.eveonline.com/en/wiki/ISK_faucet) which in my experience can reasonably vary something like 10 million per hour up to about 100 million per hour. This may be misleading since 100 million an hour in EVE is not going to be something you could reasonably do on a 1 month old character (roughly the age of our Dust 514 chars).

Generally I would support a fully open economy between EVE/Dust. Having played EVE for several years now I am always amazed at the EVE market's ability to self correct. I don't think that adding Dust 514 to the mix would be as scary as people think. I also think that if Dust ever does reach the kind of end game seen in EVE then isk will be a very much secondary factor. Isk very rarely (if ever) is the determining factor in deciding major conflicts. Still as it stands now it looks to me like there need to be more isk faucets in Dust and Dust mercenaries need a way to be able to monetize their services better if linking the two economies was to work.