{"data":{"id":"us/40-cfr-421.264","jurisdiction":"us","citation":"40 CFR 421.264","heading":"Standards of performance for new sources.","body":"Any new source subject to this subpart shall achieve the following new source performance standards:\n(a) Furnace wet air pollution control.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of precious metals, including silver, incinerated or smelted\nCopper 5.760 2.745\nCyanide (total) 0.900 0.360\nZinc 4.590 1.890\nCombined metals 1.350\nAmmonia (as N) 599.900 263.700\nTotal suspended solids 67.500 54.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(b) Raw material granulation.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of precious metals in the granulated raw material\nCopper 0.819 0.390\nCyanide (total) 0.128 0.051\nZinc 0.653 0.269\nCombined metals 0.192\nAmmonia (as N) 85.310 37.500\nTotal suspended solids 9.600 7.680\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(c) Spent plating solutions.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/liter of spent plating solution used as a raw material\nCopper 1.280 0.610\nCyanide (total) 0.200 0.080\nZinc 1.020 0.420\nCombined metals 0.300\nAmmonia (as N) 133.300 58.600\nTotal suspended solids 15.000 12.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(d) Spent cyanide stripping solutions.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of gold produced by cyanide stripping\nCopper 4.736 2.257\nCyanide (total) 0.740 0.296\nZinc 3.774 1.554\nCombined metals 1.11\nAmmonia (as N) 493.200 216.800\nTotal suspended solids 55.500 44.400\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(e) Refinery wet air pollution control 2.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of precious metals, including silver, produced in refinery\nCopper 1.280 0.610\nCyanide (total) 0.200 0.080\nZinc 1.020 0.420\nCombined metals 0.300\nAmmonia (as N) 133.300 58.600\nTotal suspended solids 15.000 12.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(f) Gold solvent extraction raffinate and wash water.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of gold produced by solvent extraction\nCopper 0.806 0.384\nCyanide (total) 0.126 0.050\nZinc 0.643 0.265\nCombined metals 0.189\nAmmonia (as N) 83.980 36.920\nTotal suspended solids 9.450 7.560\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(g) Gold spent electrolyte.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of gold produced by electrolysis\nCopper 0.011 0.005\nCyanide (total) 0.002 0.001\nCombined metals 0.003\nZinc 0.009 0.004\nAmmonia (as N) 1.160 0.510\nTotal suspended solids 0.131 0.104\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(h) Gold precipitation and filtration.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of gold precipitated\nCopper 5.632 2.684\nCyanide (total) 0.880 0.352\nZinc 4.488 1.848\nCombined metals 1.320\nAmmonia (as N) 586.500 257.800\nTotal suspended solids 66.00 52.800\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(i) Platinum precipitation and filtration.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of platinum precipitated\nCopper 6.656 3.172\nCyanide (total) 1.040 0.416\nZinc 5.304 2.184\nCombined metals 1.560\nAmmonia (as N) 693.200 304.700\nTotal suspended solids 78.000 62.400\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(j) Palladium precipitation and filtration.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of palladium precipitated\nCopper 7.680 3.660\nCyanide (total) 1.200 0.480\nZinc 6.1200 2.520\nCombined metals 1.800\nAmmonia (as N) 799.800 351.600\nTotal suspended solids 90.000 72.000\npH (1) (1)\n1 Within the range of 7.5 to 10.00 at all times.\n(k) Other platinum group metals precipitation and filtration.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of other platinum group metals precipitated\nCopper 6.656 3.172\nCyanide (total) 1.040 0.416\nZinc 5.304 2.184\nCombined metals 1.560\nAmmonia (as N) 693.200 304.700\nTotal suspended solids 78.000 62.400\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(l) Spent solution from PGC salt production.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of gold contained in PGC product\nCopper 1.152 0.549\nCyanide (total) 0.180 0.072\nZinc 0.918 0.378\nCombined metals 0.270\nAmmonia (as N) 120.000 52.740\nTotal suspended solids 13.500 10.800\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(m) Equipment and floor wash.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of precious metals, including silver, produced in refinery\nCopper 0.000 0.000\nCyanide (total) 0.000 0.000\nZinc 0.000 0.000\nCombined metals 0.000\nAmmonia (as N) 0.000 0.000\nTotal suspended solids 0.000 0.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(n) Preliminary treatment.\nNSPS for the Secondary Precious Metals Subcategory\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/troy ounce of total precious metals produced through this operation\nCopper 64.000 30.500\nCyanide (Total) 10.000 4.000\nZinc 51.000 21.000\nCombined metals 15.000\nAmmonia (as N) 6665.000 2930.000\nTotal Suspended Solids 750.000 600.000\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS","PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY","Subpart X—Secondary Precious Metals Subcategory"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"98346946f6514ad31cacea692e48a0d0881e6e73a14682300dd348bc9464e966","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-421.263","next":"us/40-cfr-421.265"},"notice":"GroundRules: Original legal text. Not legal advice."}