The refinery system in EVE is based off of five variables that together determining your refining yield. They are:

• Your Reprocessing skill level
• Your Reprocessing Efficiency skill level (requires Reprocessing V)
• Your Ore Processing skill level
• Effect of any refinery implants
• Your standing toward the corporation owning the station where you want to refine you ore
• The refining equipment of the station

Before we continue let me just give a brief word about implants. Implants are a great asset for any refinery character, since they allow attain a Net Yield of 100% (at a 40% station) without the months of extra training to get all of your ore processing skills to 5. At the time of writing, there are currently three tiers of refinery implants, all of which are for implant slot 8. They are as follows:

As you have likely already figured out if you read through the Refining section (or played EVE much at all really), the bonuses from your skills stack. So since your Mining skill gives you a 5% bonus to mining yield per level, if you trained your Mining to level 4 you would be getting 5% * 4 = 20% bonus from that particular skill. Furthermore, the bonus you get from a skill is added to any other bonuses you get to that particular ability, such as Astrogeology which also gives a bonus to mining.

Cycles determine how many seconds your laser needs to complete a full, well “mining cycle”. The ore you mined will appear in your cargo hold at the end of that cycle. Named, T1, and T2 mining lasers have a cycle of 60 seconds (1 minute) and strip mining lasers (T1 and T2) as well as the Modulated Deep Core Miner II have a cycle of 180 seconds (3 minutes); but also have a much higher yield in comparison to lasers to make up for the greater cycle time. Ice harvesters will be covered in a later section, as the whole ice mining system is quite different from the asteroid mining system.

Cycles and yield are directly linked. Because of the cycle time difference between strip miners and mining lasers, that makes comparing the yield of a mining barge, and the previously mentioned Venture mining frigate difficult. We could divide the barge's yield by three to bring it to 60 seconds, or bring both of them on a per hour ratio, but this is not precise because of the way EVE truncates the number of units of ore you get per cycle.

Since we know strip miners do 20 cycles per hour and mining lasers 60 cycles per hour, to make the comparisons as accurate as possible, we'll once a again use Arkonor as our comparison ore, and compare how many units of Arkonor a mining strip/laser will harvest compared to another. By taking the yield over the period of an hour we will get a slightly more accurate yield.

Additionally it should be noted that the cycle time of your mining laser is not a cooldown such as you would see with a ship's offensive lasers, instead it harvests the ore continuously throughout the cycle of the module, depositing the ore into the hold at the end of each cycle. However, if the mining strip/laser is deactivated partway through its cycle, you will receive the amount of ore corresponding to how far through the cycle you were at the point of deactivation. So if for example you stop a mining laser with a cycle time of 60 seconds at around the 30 second mark of its cycle, you will receive approximately 50% of the ore that you would normally get from a full cycle.

Here's a table to summarize the different mining amount of each laser and their cycle times:

For now don't be concerned about mining crystals; they will be covered in depth later on in this guide.

It may be easy for some to become confused as to the amount of ore they will get when doing a “show info” on their strip or mining laser. It's in fact very simple to find out, you just have to know how. You simply have to divide your yield per cycle by the volume of the ore you're mining, and truncate the result.

Since mining lasers and strip miners always mine the same volume of ore throughout their cycle, regardless of the number of units in that volume, a more useful measure of how many minerals you are actually mining over a given period of time can be determined from the refining yield per m³ of ore, rather than per batch. This also makes calculating the transport and storage needs of your future minerals simpler, as well.

The following table shows the yield per m³ of each type of basic ore (see also ore.cerlestes.de):