当前位置: X-MOL 学术J. Great Lakes Res. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Copper-rich “Halo” off Lake Superior’s Keweenaw Peninsula and how Mass Mill tailings dispersed onto tribal lands
Journal of Great Lakes Research ( IF 2.2 ) Pub Date : 2020-10-01 , DOI: 10.1016/j.jglr.2020.07.004
W. Charles Kerfoot , Noel Urban , Jaebong Jeong , Carol MacLennan , Sophia Ford

Abstract Over a century ago, shoreline copper mills sluiced more than 64 million metric tonnes of tailings into Lake Superior, creating a “halo” around the Keweenaw Peninsula with a buried copper peak. Here we examine how tailings from one of the smaller mills (Mass Mill, 1902–1919) spread as a dual pulse across southern Keweenaw Bay and onto tribal L’Anse Indian Reservation lands. The fine (“slime clay”) fraction dispersed early and widely, whereas the coarse fraction (stamp sands) moved more slowly southward as a black sand beach deposit, leaving scattered residual patches. Beach stamp sands followed the path of sand eroding from Jacobsville Sandstone bluffs, mixing with natural sands and eventually adding onto Sand Point, at the mouth of L’Anse Bay. Dated sediment cores and a multi-elemental analysis of the buried Cu-rich peak in L’Anse Bay confirm a tailings origin. Copper concentrations are declining in the bay, yet copper fluxes remain elevated. The spatial and temporal studies underscore that enhanced sediment and copper fluxes around the Keweenaw Peninsula largely reflect historic mining releases. Mercury is correlated with copper, yet mercury concentrations and fluxes remain relatively low in Keweenaw Bay compared to nearby Superfund sites (Torch and Portage Lakes), perhaps reflecting the absence of smelters on Keweenaw Bay. Tribal efforts to remediate contamination are progressing, but are hindered by recent high water levels plus severe storms. The long-term repercussions of Mass Mill discharges caution against mine companies discharging even small amounts of tailings into coastal environments.

中文翻译:

苏必利尔湖 Keweenaw 半岛附近富含铜的“光环”以及 Mass Mill 尾矿如何分散到部落土地上

摘要 一个多世纪以前,海岸线铜厂将超过 6400 万吨尾矿倒入苏必利尔湖,在基威诺半岛周围形成了一个“光环”,铜峰被掩埋。在这里,我们研究了来自较小工厂之一(Mass Mill,1902-1919 年)的尾矿如何以双重脉冲的形式穿过 Keweenaw 湾南部和部落 L'Anse 印第安人保留地。细粒(“黏土”)分散较早且广泛,而粗粒(印记砂)作为黑沙滩沉积物向南移动更慢,留下零散的残留斑块。海滩沙子沿着从雅各布斯维尔砂岩悬崖侵蚀的沙子路径,与天然沙子混合,最终添加到位于 L'Anse 湾口的 Sand Point。L'Anse Bay 埋藏的富铜峰的年代沉积岩心和多元素分析证实了尾矿的起源。海湾中的铜浓度正在下降,但铜通量仍然很高。空间和时间研究强调,基威诺半岛周围沉积物和铜通量的增加在很大程度上反映了历史性的采矿释放。汞与铜有关,但与附近的超级基金站点(火炬湖和波蒂奇湖)相比,基维诺湾的汞浓度和通量仍然相对较低,这可能反映了基维诺湾缺乏冶炼厂。修复污染的部落努力正在取得进展,但受到近期高水位和严重风暴的阻碍。
更新日期:2020-10-01
down
wechat
bug