But the difficulties were overcome and, as planned, the Commission drafted the report that was published in the Bulletin of the Corps of Mining Engineers of Peru in 1904. In those pages, Atacocha, now directly referenced, appears as one of the most important mining districts in the province of Cerro de Pasco. The report reads:

“In addition to the Cerro de Pasco valley, the province bearing this name has other mining centers that surely offer profitable prospects for investors interested in performing systematic surveys. Among the most important are: Huayllay, Colquijirca, Quinua, Vinchos, Ulcumayo, Anamaray, Atacocha and Mosca, with various lead, copper, silver and gold ores, though their importance cannot be measured yet due to the current small-scale of extraction”. 

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Four years later, in 1908, the Cerro de Pasco Commission submitted a second report, prepared by A.C. Gastelumendi, stating: 

“... the rise in the price of metals, which reached its peak in 1906, contributed to the greater development of the mining industry, especially small-scale industry, which in 1907 fell again with the decrease in prices. But this discouraging perspective did not affect large-scale industry, which, prudently based on moderate prices, has continued to progressively advance. Thus, the work by companies such as Concordia and Venus in Huayllay, and in Goyllarisquisga, Quishuarcancha, Atacocha, etc., continues to expand remarkably, with shafts equipped with new modern facilities, with larger capacity, and the opening of adits for the mines.”

In the 1908 report, twenty-nine mining concessions were located in the Atacocha area. At that time, the labor force was estimated at approximately eighty workers engaged in extracting some nine hundred tons of ore per year.

The references to Atacocha, contained in general studies, gave way to the report published by Luis F. Díaz in 1909 on "The Mining Region of Atacocha", now in a more specific and detailed form. That is why it is considered to be the first known study on the Atacocha deposit. In addition to mining operations, it includes observations on the surrounding scenery:

“Among the mining regions located in the vicinity of the town of Cerro de Pasco, the Atacocha region may hold an importance comparable to that of the Huallay region. Maybe both of these will be the ones in the province that will take the most advantage of Cerro's mining progress and it would not be surprising that when that seam is depleted or when the mining spirit in our country is further pursued, Atacocha and Huayllay will the ones that will maintain its fame of traditional richness.”

Likewise, the report describes details on location, operations development, costs and productivity:

“The Atacocha region is located 16 km to the northeast of the Cerro de Pasco region and is linked to it partly by the road from this city to Huanuco and partly by a special road that turns off just before reaching Quinua. The first section follows a broad bridle path, maybe one of the best in our mountains, but the section that accesses the Atacocha mountain-pass is extremely bad, becoming impassable in the rainy season.”

"Work is done by contract, paying 35 soles per meter of adit and per ton of metal having a grade higher than 60% lead.”

“The cost of extraction is eight soles per ton, and its transport to Cerro costs 0.40 soles per quintal.”

“The great abundance of ore in the Atacocha region and its high proportion of Zn leads us to believe that the product obtained from mechanical concentration may, if not pay for, at least help to cover a large part of processing expenses.”

“Atacocha can yield 50 to 55% grade Zn concentrate and lead concentrate containing silver and gold.”

The possibilities were there and so J.H. Fleming, who at the time was operating the Tres Mosqueteros and Dora mines extracting lead and silver ore for direct exportation, understood it. Fleming had being Mining Superintendent at the Cerro de Pasco Mining Company, as had H. Rally and J.D. Torbert. They partnered with T.N. Brown, cashier at the Cerro de Pasco Mining Company, and Carlos Gómez Sánchez, an attorney-at-law, to found the Pucayacu Mining Company in 1915. The company was to operate in the Atacocha region performing certain mining operations. For that purpose, a small cleaning plant was installed to concentrate ore and obtain high-grade lead, silver and gold. The region became more active, though with a limited scope, by using basic operating techniques. These activities were in addition to the operations being carried out to the east of Atacocha, in the Ayarragra area, by Emilio Tábori in the Parlamento and La Poderosa Mines, and by Agustín Otrera in the El Congreso mine. W.C. Dawson, on his part, was extracting lead sulfide and blende from the veins of the Kitty, Carmen, Kathleen and San Juan concessions.

Meanwhile, on the same year the Pucayacu Mining Company was founded, the Cerro de Pasco Mining Company decided to make a series of claims in the Atacocha area, in light of the results of studies carried out by the geologist C.M. Farnham. Months later, in October 1915, the Cerro de Pasco Mining Co. merged with the Morococha Mining Co. and with the Cerro de Pasco Railway Co. As a result of the merger, the new Cerro de Pasco Copper Corporation was created, though, for various reasons including the scarce surface evidence of mineralization, it showed no great interest in the Atacocha area.