Aspect-Oriented Requirements Engineering focuses on the identification and modularisation of crosscutting concerns at early stages. There are different approaches in the requirements engineering community to deal with crosscutting concerns, introducing the benefits of the application of aspect-oriented approaches at these early stages of development. However, most of these approaches rely on the use of Natural Language Processing techniques for aspect identification in textual documents and thus, they lack a unified process that generalises its application to other requirements artefacts such as use case diagrams or viewpoints. In this paper, we propose a process for mining early aspects, i.e. identifying crosscutting concerns at the requirements level. This process is based on a crosscutting pattern where two different domains are related. These two different domains may represent different artefacts of the requirements analysis such as text and use cases or concerns and use cases. The process uses syntactical and dependency based analyses to automatically identify crosscutting concerns at the requirements level. Validation of the process is illustrated by applying it to several systems and showing a comparison with other early aspects tools. A set of aspect-oriented metrics is also used to show this validation.