December 11, 2003
Dear Mr. Purcell:
I am writing on behalf of the Rio Colorado Reclamation Committee (RCRC) with comments on the "Draft Sampling and Analysis Plan for Investigation of Historic Tailing Spill Deposits, Molycorp, Inc. Superfund Site, Questa, NM" dated May 29, 2002. In your cover letter dated November 14, 2003 you mention that this Plan is not final. We hope that the following comments can be incorporated into the Plan to address some major deficiencies.
The RCRC has serious concerns that the largest "spill" of tailings in Questa, the use of tailings for bedding material in water lines, has not been acknowledged, sampled, or mapped in the draft Plan. Any tailings found outside of the pipeline or at the tailing ponds have been spilled, even if the spill was inadvertent, as was the use of tailings for bedding material. The Village of Questa has stated that tailings were used for bedding material in 1968 when a new water system was built and later when major repairs and upgrades were made to the system. Several recent water line breaks and the recent (November 17th) dredging of Hunt's Pond have revealed tailings in water line trenches. The NMED and EPA have collected water samples from some residences in Questa to determine whether contaminants from these tailings have entered the water supply. To date, these samples appear to show no effects from these tailings in residential water lines. However, these samples provide no information on the contamination to local water supplies and effects on human health that may have occurred over the past 35 years.
Members of the RCRC are concerned that the EPA and state agencies are not fully investigating the issue of the tailings bedding material to fully determine the impacts on water users in Questa. The analyses that the EPA and state have done to date to determine contamination are, at best, inconclusive and any health effects resulting from the use of tailings in the water lines have not yet been determined. The RCRC believes that the Village's water lines create the conditions to cause "back-siphonage" whenever a line break occurs and water pressure is cut off as repairs proceed. We urge EPA to research the website of the American Backflow Prevention Association (ABPA) at www.abpa.org to confirm that "back-siphonage" is a potential problem in the Questa water lines that must be addressed immediately.
The recent dredging of Hunt's Pond revealed a "1-foot wide by 1-foot deep" deposit of tailings in the water/sewer/gas lines exposed by the dredging and draining of the Pond (see internal Molycorp memo of November 18, 2003 from Anne Wagner). Tailings cut by the trench created to drain Hunt's Pond were inadvertently flushed into the Red River when the Taos County Soil Conservation District (SCD) drained the Pond on November 17th. The SCD has been informed of the problem and has stopped work on the Pond until the tailings issue is resolved.
One previous excavation (November 2002) of the same water line adjacent to the residence of Roberto Vigil also revealed tailings used for backfill. If these tailings are present in the water lines from the Hunt's Pond area to the Vigil residence, there could be several hundred cubic yards of tailings in this section of the line alone. Given that tailings have also been noted in water-line excavations in other parts of Questa, this issue must be resolved immediately to protect public health.
Recommendation: Because Molycorp has been dredging and removing tailings wherever they are found (e.g., Upper Sump Dump, Hunt's Pond), the same approach should be applied to tailings in water lines. The RCRC further recommends that EPA take the following actions to address these issues of concern in the RI/FS process:
The possible presence of cyanide in some of the older (pre-1970) tailing deposits is of particular concern. Because cyanide was used to enhance flotation in tailings generated from 1965-1970, older buried tailings could contain this highly toxic compound. The RCRC notes that total cyanide is being analyzed for in groundwater samples from the wells adjacent to the Upper and Lower Sump Dumps, but not in tailing or sediment samples.
Recommendation: EPA should require cyanide analyses from any tailing spills that occurred before Molycorp stopped using cyanide in its milling process.
The following statement made on page 4-2 of the Plan is premature: "Irrigation ditch alignments did not yield significant signs of tailings." Because of the dozens of tailing spills directly into the Red River and its associated irrigation ditches (acequias), it is highly likely that some residual tailings remain in the bottom of these ditches buried by other sediments. A visual inspection of the acequias would not reveal conditions in the bottom of the ditch.
Recommendation: The EPA should require Molycorp to collect sediment samples from the bottoms of both the North and South acequias to confirm that no buried tailings are located in these ditches. Using spills located on maps E-1, E-2, and E-3, EPA should devise a supplemental sampling plan that would fully characterize sediments in the acequias from the easternmost headgates all the way through the village.
Another statement made on page 4-3 of the Plan requires comment: "Tailings material was not observed or identified in the stream channel or in the immediate riparian stream margins." Again, this statement appears to be made on the basis of an incomplete visual inspection of the stream channel. Unless the URS consultants physically waded down the Red River from the mill area to the pipeline crossing at the Lower Sump Dump and sampled systematically, it is not possible to conclude that no tailings exist in the stream channel itself.
Recommendation: EPA should require that Molycorp consultants wade down the Red River from the mill area to the pipeline crossing point to locate any buried tailings that may exist in the stream channel itself. If tailings are found, they should be sampled according to the approved protocol.
The RCRC appreciates the opportunity to comment on this Plan. We hope that these comments will lead to additional sampling of tailings in water lines, the acequias, and in the stream channel. Please contact Roberto Vigil of the RCRC if you have any questions.