Originally Posted by davor rudar

Hello to everybody!

I would like to know if somebody have experience with exploatation of granite for technical stone purpose (aggregates for concret and road or railway construction). In my country, we don't have exploatation of granite for technical stone purpose. Only exploatation of granite is for monumental or architectural stone and this exploatation is small.

Our company have opportunity to do investigation works in one granite deposit.

If somebody could tell me something about exploatation of granite for technical stone purpose, I will be very thankful.

Best regards!

Greetings and salutations Davor,

I hope that by now you are using tire protection chains to thier full advantage.

I am glad to here you have a granite deposit to break for aggregate as it is a

common stone product used on this side of the pond for a stone aggregate.

Granite is used in many states in the United States simply because it is the only

stone aggregate they have to use for an aggregate for railroad ballast and

foundation stone ballast.

It is used heavily in The States of Texas and Georgia for example.

In The State of Texas hundreds of thousands tons of Granite was used to rebuild

Galveston, Texas and create stone breakwaters after the first recorded great hurricane

that destroyed Galveston, Texas.

In the State of Georgia it used for road building and aggregate in cement.

In some locations a large earthmover is used to rip the granite beds to break the granite

deposit for recovery and crushing to create aggreagates and stone dust.

The major concern is the strength of the granite that you have the opportunity to mine,

which will affect its ability to be used for an intended purpose.

You will need to use a core drill to take numerous samples to effectively determine

its Mohs or Rockwell hardness and its suitability for an intended use.

Please keep us informed as many of of us in the business always enjoy hearing of new

deposits. ■

During the mid 80's Foster Yeoman developed the Glensanda operation in the Hebrides. The island was solid granite, give or take a bit of grass and guano, which was mined so that the ships were loaded on the seaward face and the working were unseen from the surrounding inshore islands. The thinking was similar to the Kinross coal export operation some 500years earlier. A particular feature was the radio controlled ship loader built by Strachtan & Henshaw of Bristol. If you pronounce Strachan as Strawn you might be able to glean some information from them. ■

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Originally Posted by davor rudar

Hello to everybody!

I would like to know if somebody have experience with exploatation of granite for technical stone purpose (aggregates for concret and road or railway construction). In my country, we don't have exploatation of granite for technical stone purpose. Only exploatation of granite is for monumental or architectural stone and this exploatation is small.

Our company have opportunity to do investigation works in one granite deposit.

If somebody could tell me something about exploatation of granite for technical stone purpose, I will be very thankful.

Best regards!

Here in Australia, my family owned a pink granite quarry and it was used for every purpose and the crushing was very difficult and extremely abrasive on plant and machinery and as lzaharis has indicated, it is razor sharp on anything that is contacts. Our quarry, as most granite in the east of Australia is on the Southern side of the mountains with the softer rock formations mainly on the mountains Northern sides. The pink granite was slabby and the fine fissures had 'Dendrite Fern Patterns up the full 500 foot height and 1500 feet length of the quarry. There was also some 'Gun Metal Blue/Grey" Bronze(the material was a tin and copper base that electric arc welding could be caused as we tried this for interest sake) rock inclusions that had no seams or fissures and this rock broke into a saucer plate style shape and was so hard that 450 grade steel was peeled cut when impacted on the webs of the feed hoppers and grizzly bars. It was apparent that we should avoid putting this rock into the crushers as it overloaded the crushers and was the cause of broken shafts and split mainframes. After a short time of operations, I worked out how to mitigate the abrasion and damage to crushing equipment & machinery. I also managed to crush & get 'Cubical' aggregate from the 320mpa pink granite that consistently outputs as a [flaky / shard like] product under the general manufacturers operations manuals and representatives recommendations. After changing the operating manner in which I crushed the rock [reduction], I lowered our power costs to 25% compared to our first 6 months and of the previous owners records and also reduced the damage and wear & tear on the crushers, feeders and all ancillary plant. Another aspect was I changed the recommended blast pattern from 12 and 10 feet to 8 feet diamond pattern and used a different blast medium that was a slower burn 'Molasses & Nitram(not Nitropril)' ANFO mixture which gave a better fracture of the base rock. I also gained better quality of product by opening up the crushers to maximum and flooding the crusher chambers which resulted in massive reductions of the manganese & bearing wear but the best part was the $3,000.00 per week electrical power dropped to under $700.00. The one thing that wore faster was the screen decks as the product was now in a fully recirculating circuit as the product reduction rates was much slower but the output far exceed the manufacturers specified maximum for the crushers. The oversized was put aside for Armour rock to reduce handling and this was very useful in Sea Water as it did not break down when soaked as in the Atterberg & CBR(California Bearing Ratio) Testing.

I hope you do well and that this bit of information will help your exploration. ■