The following is an excerpt from a geophysical report. It says that the cut grids are 200m apart which means that the drilling crew / geologists probably used GPS's to locate the drill holes (Not # 3 and #4) that aren't directly on a grid line. For those that have not used a GPS to translate between NTS grids and a local grid it can be quite hard...hence a possible placement error could occur. The initial holes were most likely directly on a grid line which makes there position accurate.
Rockaur
http://www.norontresources.com/projects/Noront_Ground_report.pdf
5 GROUND SURVEY GRIDS
Ground survey grids were cut with a line interval of 200 metres, perpendicular to a base
line. The location of the grid was established using a GPS reference. The data was
collected and presented with reference to line and station. A transformation to
cartographic map coordinates was calculated based on the following reference points.
Grid 1
Line Station UTM-E UTM-N
0N 0+00E 544,308 5,839,294
0N 60+00E 548,670 5,843,401
Grid 2
Line Station UTM-E UTM-N
0N 0+00E 552,100 5,846,797
0N 70+00E 556,987 5,851,779
GRS 1980 ellipsoid, NAD 83 datum, UTM zone 16N ( cm 87º W )
