Diamond Drill Sampling Methods
In diamond-drill work, a true sample consists of all the material cut by the bit—both core and cuttings. As the recovery of this sample is the object of diamond drilling, the utmost care should be taken to secure it. Speed of drilling and low costs are of little value if an inaccurate sample is obtained. […]
Mineral Vein Formation Mechanism
A vein may be defined as an aggregation of mineral matter, more or less tabular or lenticular in form, which was deposited from solution and is of later origin than the inclosing rock. This definition differs from the one found in many textbooks in that no assumption is made as to the origin of the space […]
Geology of Zinc Deposits MVD
I consider the lead and zinc deposits of the Mississippi Valley to be the result of descending waters. There are many features that we have not determined and yet when you see the general field relations, it seems to me that the cause and effect can be well explained by descending circulation. In the Joplin-Miami […]
Metalliferous Ore Deposit Exploration
The exploration of deposits of the metals will never become an exact science. There will always be an element of uncertainty in prospecting and developing mines. In countries where the surface has been closely scrutinized, most of the deposits whose outcrops contain valuable metals have probably been discovered. Many metalliferous deposits, however, are normally so […]
Drill Holes Assay Result Interpretation
In the exploration of a copper deposit by drilling, obvious advantages are to be gained from a distinction between primary and secondary ore. Perhaps the chief of these is the aid which such a distinction renders in determining where a given hole should stop. The copper assay, often a sufficient guide, cannot always be exclusively […]
Bournonite, Jamesonite, and Calamine Occurences
The results of these investigations show that bournonite (PbCu-SbS3) is present in the ores in greater or less quantity. This fact has never before been reported, as far as can be learned. The failure to recognize this mineral is due to its similarity to tetrahedrite, with which it has probably been confused during a long […]
Sampling Ore from Hammer Drills
The use of hammer drills for obtaining samples in underground work has increased in recent years. This method has advantages where holes are short, ground conditions preclude the use of diamond drills, satisfactory core recovery is impossible, or sludge samples are accurate enough for the purpose in view. Holes may be drilled at all angles […]
Drill Core Sampling
The advantages of obtaining core samples that provide a visual record of the rocks and ores sampled and at the same time furnish samples for assay have been pointed out under the caption Exploration by Drilling. The diamond drill, which employs either carbons or bort as cutting media, has been the type of core drill […]
Ore “Rock” Face Sampling
Face sampling is the cutting of pieces of ore and rock from exposed faces of ore and waste. The faces may be natural outcrops or faces exposed in surface trenches and pits or in the backs, walls, and floors of development openings and stopes. Face samples may be taken: by cutting grooves or channels of […]
How Much is the Cost of Mining Exploration
In the preceding pages some unit costs of sinking, drifting, cross-cutting, and drilling have been presented, together with a few costs covering entire churn-drilling campaigns. Few figures are available covering the total cost of exploring a property before reaching a decision to develop it for production. However, figures are available covering expenditures for exploration and […]