We have a client who is considering options for building a compacted aggregate path and driveway. One of the products the stone company offers it called copper slag.

Copper slag is the waste product of copper smelting, and in this case the term is NOT just a description of the color of some natural stone. It is truly copper slag from smelting operations. Apparently it is used for a number of things including sand-blasting, addition to concrete mix, and as a "gravel."

I have not seen much discussion of the potential for toxic leachates, and wonder if anyone has experience with or knowledge of the potential downside in terms of environmental contamination of such a product.

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    Based on the abstract of this article, it seems that disposal of copper slag is an environmental issue in itself, and researchers are investigating ways to incorporate it into building materials (e.g. concrete) as a more sustainable means of disposal.
    – LShaver
    May 3, 2018 at 14:17

2 Answers 2


I found a (eventually political) study made by NABU Hamburg from 2013 about copper slag. They state, that several materials are included with toxic and hazardous to health impact, among others (per 1000 t of slag): lead (1t), manganese (1t), arsenic (0.37t), nickel (0.2 t), cobalt (0.3t) and some others, like antimony, cadmium, tin and chromatics.

Most of them can be washed out to ground water at short or long term.

Other source speaks about "highly dioxin contaminated sports field".


Do you you mean the proverbial "black beauty" ? If so , it has little to do with copper slag. If real copper slag : copper smelters do not throw copper away so the copper level would be in the low ppm range. And copper does not develop water soluble product under atmospheric conditions , that is why copper roofs/flashing does not wash away, it just turns green

  • No, according to the vendor, this is actually the waste byproduct of smelting copper - actual copper slag.
    – That Idiot
    May 4, 2018 at 13:28

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