Well now that I have set myself up as a goon target for who knows how long, I might as well share some knowledge with my fellow miners. This post is by no means a definitive guide, I am sure there are others far more knowledgeable than me who can also share some insight:

Mackinaws are made of paper. I don't care how you plan to tank one, they can be taken down rather easily. If a Brutix won't work, they will simply bring some friends, or a smart-bombing battleship. Therefore your idea should not be to build yourself a mackinaw tank and "ride it out" as this approach is doomed to failure. To survive this you need to change your tactics on a fundamental level.

If you can afford a Hulk or have a Hulk somewhere, fly a Hulk. Hulks can be tanked more easily with less skill and far more EHP and still remain a viable mining ship. Yes you will lose revenue since the Mackinaw pulls in 4 blocks per cycle vs the Hulk's 3 blocks - but would you rather have 75% of your ice, or have to buy a new ship?

However even if you fly a Hulk, do not get complacent. They are easily popped by disco (smart-bomb equipped) battleships or even someone with lots of skills/implants in a pimped out T2 battlecruiser.

Now to understand the adversary and his tactics: Goonswarm Federation is the 2nd largest alliance in EVE with close to 7,000 players and who knows how many neutral alts. Therefore expect them to launch organized, coordinated assaults involving several players. They have eyes in pretty much every system that matters and are constantly reporting intel back about how many miners are located where. Therefore if you are out mining it's only a matter of minutes before Goonswarm has reported you as a potential target.

This is what will happen if you're lucky: Some neutral that you've probably never seen before will show up at your belt most likely in a rookie ship or a shuttle. They'll hang around 100km or so from you or move in closer if they want to scan you to see how easy a target you'll make. Then they will warp off. A few minutes later you will see the same or a different neutral ship warp right next to your mining ship. This means the suicide-bombing ship is inbound. If you have repping support, you had better hope your repper is awake. If you are alone you should have warped the minute the neutral showed up under 3000 meters from you otherwise you are dead.

If you are not lucky, all of the above will happen with cloaky ships and your only warning (besides seeing strange people in local) is when the suicide ganker shows up at your belt. Even then it's possible to survive if your remote repper is awake - it takes a few seconds after warping to be able to lock someone up.

Usually the goons have been operating in groups of 2 or 3. A suicide bomber, a spotter and a hauler. Sometimes the hauler can double as the spotter. If you see strange industrial/transport ships show up at your belt be aware that his intent is to haul away your stuff from your wreck.

These have been their tactics so far, now let's talk about dealing with them. Buffing is good, but it's not enough. The groups that are having the most success are organizing with remote repping ships. From my personal experience just two large shield transporters are enough to protect an untanked Mackinaw from a single well-armed Brutix. The repping ship should have the miner(s) locked at all times and should be watching local and the belt for unusual/suspicious activity. Remember that a single Brutix can only engage one mining ship and hope to kill it before it gets popped by Concord. Therefore the remote repper should focus all his repping on the ship that's currently being attacked. It is quite possible, Goonswarm being the size that it is, that more than one suicide ship will show up at the same time. In which case if there is a single repper he must choose who to save. Trying to rep everyone at the same time will result in everyone being killed. Better to save one person than none at all.

Another thing I like to do, to complement the remote repping, is having a ship with neuts fitted. My choice is the Dominix because it can fit and run 6 neuts for a long time and still provide enough tank to take a hell of a beating. Neutralizers are useful for the following reason:

A suicide ganker is racing against time. He knows full well that his ship is doomed to be destroyed by concord, therefore the idea is to maximize the damage done in as little time as possible. By neutralizing his cap, you are taking away the ability to fire those very last salvos before concord shows up and kills him. This can easily turn a successful suicide gank run into a miserable failure. Neuts offer another advantage as well which I will discuss in a moment. Obviously trying to fit one ship with both reppers and neuts will end up with you floating around out of cap while your proteg+¬ is destroyed. Choose or the other, or better yet organize with someone else and divide the reponsibilities.

Another ship that can help (but has severe limitations) is a jamming ship like a blackbird, Falcon or Rook. Once the goonie attacks he sets the global criminal flag and turns red to everyone, which means he can be dealt with without problems. A jamming ship, when successful, will shut down his guns and stop the attack cold. However it is chance based and just might not work. Do not rely on ECM ships alone to protect you!

The other thing I wanted to mention is this - Goonswarm is made of human pilots not a scripted AI, so even as we speak they are switching tactics as we miners get organized into fleets. Therefore let's discuss this. Since Goonswarm is made up of nullbears with extremely deep pockets, for now they can afford all sorts of ships for suicide ganking. This includes disco (smart bomb) battleships.