He hopena maikaʻi ʻole ka mīkini mahiʻai o kēia wā i ka momona o ka lepo a ke kumu i nā pōʻino kūlohelohe. Ua loaʻa kēia hopena e kahi hui o nā ʻepekema mai Suedena, Switzerland a me ʻAmelika Hui Pū ʻIa, paʻi ʻia kāna hana ma ka puke pai Nā hana o ka National Academy of Science (PNAS).
Hoʻomaopopo ka haʻawina inā i ka hopena o 1950s, hui pū ʻia nā mea hōʻiliʻili me ka palaoa ma kahi o 4 tons, a laila hiki i nā mea hou ke kaupaona 36 tons. Hoʻolālā ʻia nā mīkini mahiʻai o kēia wā e pale i ka lepo palupalu: hana ʻia nā kaila a palupalu a ākea, e hōʻemi ana i ke kaomi ʻāina.
Akā, mālama kēia i ka ʻili o ka lepo. Akā i loko o nā papa hohonu, hoʻopili ʻia ka lepo i mea e hoʻoweliweli ʻia ai kona momona. Hoʻopili ka hoʻopili nui i ka hiki ke hele i ka wai.
"ʻO kēia paha kekahi o nā kumu o ka emi ʻana o nā mea kanu a me ka piʻi ʻana o ka nui o nā waikahe i ka honua," wahi a ka mea kākau noiʻi ʻo Professor Thomas Keller mai ke Kulanui ʻo ʻEpekema Kūʻai ʻo Swedish.
Ua palapala ʻia ʻo Keller a me nā hoa hana i nā ʻāina i pilikia loa i ka "hoʻopili paʻa ʻana" o ka lepo. ʻO nā wahi pilikia loa ʻo Australia, ʻEulopa, ʻĀkau a me ʻAmelika Hema. Manaʻo ka poʻe ʻepekema ua pōʻino loa ka hapalima o ka ʻāina mahiai o ka honua a ʻaʻole hiki ke hoʻihoʻi hou. I ka liʻiliʻi liʻiliʻi, pili ka compaction i nā lepo ma Asia a me ʻApelika, kahi i kiʻekiʻe ʻole ai ka pae o ka mīkini mahiʻai.