The details of a resource deposit (Mining ) are initially unknown to you. You can change this with Surveying.
Surveying is the process of scoping out a resource deposit (both on planets and asteroids) to determine:
Surveying is carried out by Surveying Modules that are attached to spacecraft, and come in a variety of flavors that give you information about a deposit at varying levels of precision.
Survey resources from the comfort of your own planetary orbit! Telescopes survey any deposit from anywhere in the Solar system and take the least time to complete a survey. They will tell you what resources are likely to be found in a deposit, but they will not yield you any details about the amount of resources a deposit contains, nor the accessibility or purity.
OR probes take a little longer than telescopes, and they must be in orbit around the celestial body you're surveying. They will tell you exactly what resources are in each surveyed deposit, as well as an imprecise range of the amount, accessibility and purity of each deposit.
AR probes fly much closer to the ground than OR probes. They take longer, but will give you a more precise range of a deposit's stats.
Surface probes are actual, boots (bots?) on the ground surveying vessels that can directly interact with the surface and subsurface of a celestial body. They take the longest of any surveying method, but they will give you an exact breakdown of the amount, accessibility and purity of each resource in a deposit.