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Heading: 1.1.3Still Looking - NASA Gravel
You may have seen my other posting - here's a little more info. Please reply with your contact info if you have or know of a source that meets these requirements.

Part of the current Specification, written 10 yrs ago or so, reads as follows: "Provide aggregates free from lumps and balls of clay, organic matter, objectionable coatings, and other foreign materials. Aggregate shall be particles of uniform density. Coarse aggregate shall have a loss not greater than 3 percent weighted average at five cycles when tested for soundness in magnesium sulfate in accordance with ASTM C 88. Aggregate shall have a percentage of wear not to exceed 20 after 500 revolutions as determined by ASTM C 131. Aggregate shall have a hardness on the MOHS Scale of 7 or greater and shall contain not less than 55 percent of the particles having a visual roundness of at least 0.7 on the Krumbein Scale and a visual sphericity of not less than 0.83 on the Rittenhouse Scale. When aggregate is supplied from more than one source, aggregate from each source shall meet the requirements set forth. The selected requirements shall be mandatory for the entire job."

The gravel must be rounded because under the extreme weight, the Crawler tracks need a little bit a slippage in order to manuever or turn. Angular gravel or crushed rock will not work, nor will sand or concrete surfacing. The USACOE from the 60s considered adding talc to further reduce friction. I'm not sure what the Env issues related to that but please don't reply on just that because it will probably not be considered. I have discussed glacial sources made up of hard igneous rock in rounded gravel--this seems like best bet as long as there is not any signif amount of softer rock like limestone, shale, siltstone, etc.

Currently talking to sources in Wisconsin and NY. Again, include your contact info if you have knowledge of qualifying sources.

Thanks for the help,
Allan Biddlecomb

Allan Biddlecomb

Hi Allan. Tom from Canada,You are looking for a very hard rock in the Quartz department.Really hard to find in open pit locations. Best bet is to try and find a underground mine with this quartz (pre)Gold Mine.You may have to Build a tumbler of consistancy for sizing of rock to get your specs reguired for job. Best I can do for you as a Mining/Milling consultant. Good Luck and Regards Tom
Tom Lang

dear / Allan

this aggregate is avilable in egypt (flint)
this is natural source with nominal maximum size ranges from 63mm up to 5mm

you will found some defect in grading but its more durable and clean becouse its rounded due to weathering


eng / mahmoud
mobile 00971503971092
mahmoud eid
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