I am afraid we don’t have real good news in way of a cure for your situation – although, we’ve been exposed to the major aspects of your difficult situation. Let’s begin with the use of impact type crushers in high silica reduction applications. We were exposed to one of our large customer’s high volume use of wear steel in the production of shaped and colored granules. The product they make requires several stages of conventional crushing. In most cases 5 stages of reduction are required to take quarried material to finished sieve sized finished product. They experimented extensively with impact type crushers while trying to reduce stages of operation. The conclusion was drawn by a pretty high powered group -- that if the silica content was over .4 in the mineral being reduced, you couldn’t afford to do the crushing with impacter type crushers. 50# hammer like parts wouldn’t last 8 hrs. So the range of service life you describe is similar. The tests conducted were funded by the manufacturer of the crushers and fact was they left the project with their tails between their legs. We learned a lot from following that one. What we learned was that even with high hardness (700 bh) irons, suitable wear life couldn’t be obtained with that type of machine, in high silica applications. Your situation is worse than what I just described with quartz being all silica. This information was compiled nearly 25 years ago and that material is still being mined and crushed most successfully with a conventional 5 stage crushing operation. That begins in the quarry with the following crushing machines -- a primary gyratory, followed by a coarse crushing cone, with 2 more increasingly fine crushing cone crushers w/ the finished shaped product made in roll crushers. The second part of your dilemma being the magnetic removal of the spalled wear steel contaminants in the material -- we’ve run into that one, like yourselves, with glass sand producers. We’ve made conventional crusher wear parts from high hardness grades of carbon steel, as opposed to conventionally applied manganese steel, so as to allow similar magnetic separators to function the same way you have to -- to keep the oxidized material from discoloring the glass. Our findings in that arena, have been that when applying the high hardness carbon steels (up to 600 bh, most commonly 400 bh materials), the service life with the same kind of crusher, is typically one half of what like sizing of low silica range materials is with manganese steel. However, manganese steel applied to very high silica minerals is half of that of the carbon steels. Follow that statement carefully -- very high silica mineral crushing with manganese = very poor wear results. Very high silica mineral crushing with high hardness carbon steels improve wear life by a 2 factor, although are still a very poor half of service life manganese steel provides in lower silica bearing minerals. All is being compared in the same kind of crushing machinery with the same sizing requirements. The bottom line is, you have a bad set of conditions going for you and it’s possible the type of crushing machines you have, may not be the best choice for the material your reducing. High speed crushers will make the magnetic separators less effective as well. Your costs have to be at minimum triple that of conventional aggregate crushing. That’s the best we can come up with from here -- you might ask yourself the question whether or not you have the best equipment for the job.